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Reformat rest of the design patterns - Issue #224

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This commit is contained in:
Ankur Kaushal 2015-11-01 21:29:13 -05:00
parent 449340bd2b
commit 306b1f3d31
337 changed files with 6744 additions and 6851 deletions
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55
double-checked-locking/src/main/java/com/iluwatar/doublechecked/locking/App.java
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@ -6,38 +6,37 @@ import java.util.concurrent.TimeUnit;
/**
*
* Double Checked Locking is a concurrency design pattern used to reduce the overhead
* of acquiring a lock by first testing the locking criterion (the "lock hint") without
* actually acquiring the lock. Only if the locking criterion check indicates that
* locking is required does the actual locking logic proceed.
* Double Checked Locking is a concurrency design pattern used to reduce the overhead of acquiring a
* lock by first testing the locking criterion (the "lock hint") without actually acquiring the
* lock. Only if the locking criterion check indicates that locking is required does the actual
* locking logic proceed.
* <p>
* In {@link Inventory} we store the items with a given size. However, we do not store
* more items than the inventory size. To address concurrent access problems we
* use double checked locking to add item to inventory. In this method, the
* thread which gets the lock first adds the item.
* In {@link Inventory} we store the items with a given size. However, we do not store more items
* than the inventory size. To address concurrent access problems we use double checked locking to
* add item to inventory. In this method, the thread which gets the lock first adds the item.
*
*/
public class App {
/**
* Program entry point
* @param args command line args
*/
public static void main(String[] args) {
final Inventory inventory = new Inventory(1000);
ExecutorService executorService = Executors.newFixedThreadPool(3);
for (int i = 0; i < 3; i++) {
executorService.execute(() -> {
while (inventory.addItem(new Item()))
;
});
}
/**
* Program entry point
*
* @param args command line args
*/
public static void main(String[] args) {
final Inventory inventory = new Inventory(1000);
ExecutorService executorService = Executors.newFixedThreadPool(3);
for (int i = 0; i < 3; i++) {
executorService.execute(() -> {
while (inventory.addItem(new Item()));
});
}
executorService.shutdown();
try {
executorService.awaitTermination(5, TimeUnit.SECONDS);
} catch (InterruptedException e) {
System.out.println("Error waiting for ExecutorService shutdown");
}
}
executorService.shutdown();
try {
executorService.awaitTermination(5, TimeUnit.SECONDS);
} catch (InterruptedException e) {
System.out.println("Error waiting for ExecutorService shutdown");
}
}
}

50
double-checked-locking/src/main/java/com/iluwatar/doublechecked/locking/Inventory.java
View File

@ -12,32 +12,30 @@ import java.util.concurrent.locks.ReentrantLock;
*/
public class Inventory {
private final int inventorySize;
private final List<Item> items;
private final Lock lock;
private final int inventorySize;
private final List<Item> items;
private final Lock lock;
public Inventory(int inventorySize) {
this.inventorySize = inventorySize;
this.items = new ArrayList<>(inventorySize);
this.lock = new ReentrantLock();
}
public boolean addItem(Item item) {
if (items.size() < inventorySize) {
lock.lock();
try {
if (items.size() < inventorySize) {
items.add(item);
System.out.println(Thread.currentThread()
+ ": items.size()=" + items.size()
+ ", inventorySize=" + inventorySize);
return true;
}
} finally {
lock.unlock();
}
}
return false;
}
public Inventory(int inventorySize) {
this.inventorySize = inventorySize;
this.items = new ArrayList<>(inventorySize);
this.lock = new ReentrantLock();
}
public boolean addItem(Item item) {
if (items.size() < inventorySize) {
lock.lock();
try {
if (items.size() < inventorySize) {
items.add(item);
System.out.println(Thread.currentThread() + ": items.size()=" + items.size()
+ ", inventorySize=" + inventorySize);
return true;
}
} finally {
lock.unlock();
}
}
return false;
}
}

6
double-checked-locking/src/main/java/com/iluwatar/doublechecked/locking/Item.java
View File

@ -6,7 +6,7 @@ package com.iluwatar.doublechecked.locking;
*
*/
public class Item {
private String name;
private int level;
private String name;
private int level;
}

10
double-checked-locking/src/test/java/com/iluwatar/doublechecked/locking/AppTest.java
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@ -11,9 +11,9 @@ import com.iluwatar.doublechecked.locking.App;
*/
public class AppTest {
@Test
public void test() {
String[] args = {};
App.main(args);
}
@Test
public void test() {
String[] args = {};
App.main(args);
}
}

68
double-dispatch/src/main/java/com/iluwatar/doubledispatch/App.java
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@ -5,46 +5,50 @@ import java.util.List;
/**
*
* When a message with a parameter is sent to an object, the resultant behaviour is defined by the
* implementation of that method in the receiver. Sometimes the behaviour must also be determined
* by the type of the parameter.
* When a message with a parameter is sent to an object, the resultant behaviour is defined by the
* implementation of that method in the receiver. Sometimes the behaviour must also be determined by
* the type of the parameter.
* <p>
* One way to implement this would be to create multiple instanceof-checks for the methods parameter.
* However, this creates a maintenance issue. When new types are added we would also need to change
* the method's implementation and add a new instanceof-check. This violates the single responsibility
* principle - a class should have only one reason to change.
* One way to implement this would be to create multiple instanceof-checks for the methods
* parameter. However, this creates a maintenance issue. When new types are added we would also need
* to change the method's implementation and add a new instanceof-check. This violates the single
* responsibility principle - a class should have only one reason to change.
* <p>
* Instead of the instanceof-checks a better way is to make another virtual call on the parameter
* object. This way new functionality can be easily added without the need to modify existing
* implementation (open-closed principle).
* <p>
* In this example we have hierarchy of objects ({@link GameObject}) that can collide to each other. Each
* object has its own coordinates which are checked against the other objects' coordinates. If
* In this example we have hierarchy of objects ({@link GameObject}) that can collide to each other.
* Each object has its own coordinates which are checked against the other objects' coordinates. If
* there is an overlap, then the objects collide utilizing the Double Dispatch pattern.
*
*/
public class App {
/**
* Program entry point
* @param args command line args
*/
public static void main( String[] args ) {
// initialize game objects and print their status
List<GameObject> objects = new ArrayList<>();
objects.add(new FlamingAsteroid(0, 0, 5, 5));
objects.add(new SpaceStationMir(1, 1, 2, 2));
objects.add(new Meteoroid(10, 10, 15, 15));
objects.add(new SpaceStationIss(12, 12, 14, 14));
objects.stream().forEach(o -> System.out.println(o));
System.out.println("");
// collision check
objects.stream().forEach(o1 -> objects.stream().forEach(o2 -> { if (o1 != o2 && o1.intersectsWith(o2)) o1.collision(o2); } ));
System.out.println("");
// output eventual object statuses
objects.stream().forEach(o -> System.out.println(o));
System.out.println("");
}
/**
* Program entry point
*
* @param args command line args
*/
public static void main(String[] args) {
// initialize game objects and print their status
List<GameObject> objects = new ArrayList<>();
objects.add(new FlamingAsteroid(0, 0, 5, 5));
objects.add(new SpaceStationMir(1, 1, 2, 2));
objects.add(new Meteoroid(10, 10, 15, 15));
objects.add(new SpaceStationIss(12, 12, 14, 14));
objects.stream().forEach(o -> System.out.println(o));
System.out.println("");
// collision check
objects.stream().forEach(o1 -> objects.stream().forEach(o2 -> {
if (o1 != o2 && o1.intersectsWith(o2))
o1.collision(o2);
}));
System.out.println("");
// output eventual object statuses
objects.stream().forEach(o -> System.out.println(o));
System.out.println("");
}
}

16
double-dispatch/src/main/java/com/iluwatar/doubledispatch/FlamingAsteroid.java
View File

@ -7,13 +7,13 @@ package com.iluwatar.doubledispatch;
*/
public class FlamingAsteroid extends Meteoroid {
public FlamingAsteroid(int left, int top, int right, int bottom) {
super(left, top, right, bottom);
setOnFire(true);
}
public FlamingAsteroid(int left, int top, int right, int bottom) {
super(left, top, right, bottom);
setOnFire(true);
}
@Override
public void collision(GameObject gameObject) {
gameObject.collisionResolve(this);
}
@Override
public void collision(GameObject gameObject) {
gameObject.collisionResolve(this);
}
}

75
double-dispatch/src/main/java/com/iluwatar/doubledispatch/GameObject.java
View File

@ -2,48 +2,47 @@ package com.iluwatar.doubledispatch;
/**
*
* Game objects have coordinates and some
* other status information.
* Game objects have coordinates and some other status information.
*
*/
public abstract class GameObject extends Rectangle {
private boolean damaged;
private boolean onFire;
public GameObject(int left, int top, int right, int bottom) {
super(left, top, right, bottom);
}
@Override
public String toString() {
return String.format("%s at %s damaged=%b onFire=%b", this.getClass().getSimpleName(),
super.toString(), isDamaged(), isOnFire());
}
public boolean isOnFire() {
return onFire;
}
public void setOnFire(boolean onFire) {
this.onFire = onFire;
}
public boolean isDamaged() {
return damaged;
}
public void setDamaged(boolean damaged) {
this.damaged = damaged;
}
public abstract void collision(GameObject gameObject);
public abstract void collisionResolve(FlamingAsteroid asteroid);
public abstract void collisionResolve(Meteoroid meteoroid);
private boolean damaged;
private boolean onFire;
public abstract void collisionResolve(SpaceStationMir mir);
public GameObject(int left, int top, int right, int bottom) {
super(left, top, right, bottom);
}
public abstract void collisionResolve(SpaceStationIss iss);
@Override
public String toString() {
return String.format("%s at %s damaged=%b onFire=%b", this.getClass().getSimpleName(),
super.toString(), isDamaged(), isOnFire());
}
public boolean isOnFire() {
return onFire;
}
public void setOnFire(boolean onFire) {
this.onFire = onFire;
}
public boolean isDamaged() {
return damaged;
}
public void setDamaged(boolean damaged) {
this.damaged = damaged;
}
public abstract void collision(GameObject gameObject);
public abstract void collisionResolve(FlamingAsteroid asteroid);
public abstract void collisionResolve(Meteoroid meteoroid);
public abstract void collisionResolve(SpaceStationMir mir);
public abstract void collisionResolve(SpaceStationIss iss);
}

50
double-dispatch/src/main/java/com/iluwatar/doubledispatch/Meteoroid.java
View File

@ -7,32 +7,36 @@ package com.iluwatar.doubledispatch;
*/
public class Meteoroid extends GameObject {
public Meteoroid(int left, int top, int right, int bottom) {
super(left, top, right, bottom);
}
public Meteoroid(int left, int top, int right, int bottom) {
super(left, top, right, bottom);
}
@Override
public void collision(GameObject gameObject) {
gameObject.collisionResolve(this);
}
@Override
public void collision(GameObject gameObject) {
gameObject.collisionResolve(this);
}
@Override
public void collisionResolve(FlamingAsteroid asteroid) {
System.out.println(String.format("%s hits %s.", asteroid.getClass().getSimpleName(), this.getClass().getSimpleName()));
}
@Override
public void collisionResolve(FlamingAsteroid asteroid) {
System.out.println(String.format("%s hits %s.", asteroid.getClass().getSimpleName(), this
.getClass().getSimpleName()));
}
@Override
public void collisionResolve(Meteoroid meteoroid) {
System.out.println(String.format("%s hits %s.", meteoroid.getClass().getSimpleName(), this.getClass().getSimpleName()));
}
@Override
public void collisionResolve(Meteoroid meteoroid) {
System.out.println(String.format("%s hits %s.", meteoroid.getClass().getSimpleName(), this
.getClass().getSimpleName()));
}
@Override
public void collisionResolve(SpaceStationMir mir) {
System.out.println(String.format("%s hits %s.", mir.getClass().getSimpleName(), this.getClass().getSimpleName()));
}
@Override
public void collisionResolve(SpaceStationMir mir) {
System.out.println(String.format("%s hits %s.", mir.getClass().getSimpleName(), this.getClass()
.getSimpleName()));
}
@Override
public void collisionResolve(SpaceStationIss iss) {
System.out.println(String.format("%s hits %s.", iss.getClass().getSimpleName(), this.getClass().getSimpleName()));
}
@Override
public void collisionResolve(SpaceStationIss iss) {
System.out.println(String.format("%s hits %s.", iss.getClass().getSimpleName(), this.getClass()
.getSimpleName()));
}
}

71
double-dispatch/src/main/java/com/iluwatar/doubledispatch/Rectangle.java
View File

@ -2,43 +2,46 @@ package com.iluwatar.doubledispatch;
/**
*
* Rectangle has coordinates and can be checked for overlap against
* other Rectangles.
* Rectangle has coordinates and can be checked for overlap against other Rectangles.
*
*/
public class Rectangle {
private int left;
private int top;
private int right;
private int bottom;
private int left;
private int top;
private int right;
private int bottom;
public Rectangle(int left, int top, int right, int bottom) {
this.left = left;
this.top = top;
this.right = right;
this.bottom = bottom;
}
public int getLeft() {
return left;
}
public int getTop() {
return top;
}
public int getRight() {
return right;
}
public int getBottom() {
return bottom;
}
boolean intersectsWith(Rectangle r) {
return !(r.getLeft() > getRight() || r.getRight() < getLeft() || r.getTop() > getBottom() || r.getBottom() < getTop());
}
@Override
public String toString() {
return String.format("[%d,%d,%d,%d]", getLeft(), getTop(), getRight(), getBottom());
}
public Rectangle(int left, int top, int right, int bottom) {
this.left = left;
this.top = top;
this.right = right;
this.bottom = bottom;
}
public int getLeft() {
return left;
}
public int getTop() {
return top;
}
public int getRight() {
return right;
}
public int getBottom() {
return bottom;
}
boolean intersectsWith(Rectangle r) {
return !(r.getLeft() > getRight() || r.getRight() < getLeft() || r.getTop() > getBottom() || r
.getBottom() < getTop());
}
@Override
public String toString() {
return String.format("[%d,%d,%d,%d]", getLeft(), getTop(), getRight(), getBottom());
}
}

14
double-dispatch/src/main/java/com/iluwatar/doubledispatch/SpaceStationIss.java
View File

@ -7,12 +7,12 @@ package com.iluwatar.doubledispatch;
*/
public class SpaceStationIss extends SpaceStationMir {
public SpaceStationIss(int left, int top, int right, int bottom) {
super(left, top, right, bottom);
}
public SpaceStationIss(int left, int top, int right, int bottom) {
super(left, top, right, bottom);
}
@Override
public void collision(GameObject gameObject) {
gameObject.collisionResolve(this);
}
@Override
public void collision(GameObject gameObject) {
gameObject.collisionResolve(this);
}
}

69
double-dispatch/src/main/java/com/iluwatar/doubledispatch/SpaceStationMir.java
View File

@ -7,45 +7,42 @@ package com.iluwatar.doubledispatch;
*/
public class SpaceStationMir extends GameObject {
public SpaceStationMir(int left, int top, int right, int bottom) {
super(left, top, right, bottom);
}
public SpaceStationMir(int left, int top, int right, int bottom) {
super(left, top, right, bottom);
}
@Override
public void collision(GameObject gameObject) {
gameObject.collisionResolve(this);
}
@Override
public void collision(GameObject gameObject) {
gameObject.collisionResolve(this);
}
@Override
public void collisionResolve(FlamingAsteroid asteroid) {
System.out.println(String.format("%s hits %s. %s is damaged! %s is set on fire!",
asteroid.getClass().getSimpleName(), this.getClass().getSimpleName(),
this.getClass().getSimpleName(), this.getClass().getSimpleName()));
setDamaged(true);
setOnFire(true);
}
@Override
public void collisionResolve(FlamingAsteroid asteroid) {
System.out.println(String.format("%s hits %s. %s is damaged! %s is set on fire!", asteroid
.getClass().getSimpleName(), this.getClass().getSimpleName(), this.getClass()
.getSimpleName(), this.getClass().getSimpleName()));
setDamaged(true);
setOnFire(true);
}
@Override
public void collisionResolve(Meteoroid meteoroid) {
System.out.println(String.format("%s hits %s. %s is damaged!",
meteoroid.getClass().getSimpleName(), this.getClass().getSimpleName(),
this.getClass().getSimpleName()));
setDamaged(true);
}
@Override
public void collisionResolve(Meteoroid meteoroid) {
System.out.println(String.format("%s hits %s. %s is damaged!", meteoroid.getClass()
.getSimpleName(), this.getClass().getSimpleName(), this.getClass().getSimpleName()));
setDamaged(true);
}
@Override
public void collisionResolve(SpaceStationMir mir) {
System.out.println(String.format("%s hits %s. %s is damaged!",
mir.getClass().getSimpleName(), this.getClass().getSimpleName(),
this.getClass().getSimpleName()));
setDamaged(true);
}
@Override
public void collisionResolve(SpaceStationMir mir) {
System.out.println(String.format("%s hits %s. %s is damaged!", mir.getClass().getSimpleName(),
this.getClass().getSimpleName(), this.getClass().getSimpleName()));
setDamaged(true);
}
@Override
public void collisionResolve(SpaceStationIss iss) {
System.out.println(String.format("%s hits %s. %s is damaged!",
iss.getClass().getSimpleName(), this.getClass().getSimpleName(),
this.getClass().getSimpleName()));
setDamaged(true);
}
@Override
public void collisionResolve(SpaceStationIss iss) {
System.out.println(String.format("%s hits %s. %s is damaged!", iss.getClass().getSimpleName(),
this.getClass().getSimpleName(), this.getClass().getSimpleName()));
setDamaged(true);
}
}

12
double-dispatch/src/test/java/com/iluwatar/doubledispatch/AppTest.java
View File

@ -10,10 +10,10 @@ import com.iluwatar.doubledispatch.App;
*
*/
public class AppTest {
@Test
public void test() {
String[] args = {};
App.main(args);
}
@Test
public void test() {
String[] args = {};
App.main(args);
}
}

14
double-dispatch/src/test/java/com/iluwatar/doubledispatch/RectangleTest.java
View File

@ -12,11 +12,11 @@ import com.iluwatar.doubledispatch.Rectangle;
*/
public class RectangleTest {
@Test
public void test() {
Assert.assertTrue(new Rectangle(0,0,1,1).intersectsWith(new Rectangle(0,0,1,1)));
Assert.assertTrue(new Rectangle(0,0,1,1).intersectsWith(new Rectangle(-1,-5,7,8)));
Assert.assertFalse(new Rectangle(0,0,1,1).intersectsWith(new Rectangle(2,2,3,3)));
Assert.assertFalse(new Rectangle(0,0,1,1).intersectsWith(new Rectangle(-2,-2,-1,-1)));
}
@Test
public void test() {
Assert.assertTrue(new Rectangle(0, 0, 1, 1).intersectsWith(new Rectangle(0, 0, 1, 1)));
Assert.assertTrue(new Rectangle(0, 0, 1, 1).intersectsWith(new Rectangle(-1, -5, 7, 8)));
Assert.assertFalse(new Rectangle(0, 0, 1, 1).intersectsWith(new Rectangle(2, 2, 3, 3)));
Assert.assertFalse(new Rectangle(0, 0, 1, 1).intersectsWith(new Rectangle(-2, -2, -1, -1)));
}
}

55
event-aggregator/src/main/java/com/iluwatar/event/aggregator/App.java
View File

@ -5,39 +5,40 @@ import java.util.List;
/**
*
* A system with lots of objects can lead to complexities when a client wants to subscribe
* to events. The client has to find and register for each object individually, if each
* object has multiple events then each event requires a separate subscription.
* A system with lots of objects can lead to complexities when a client wants to subscribe to
* events. The client has to find and register for each object individually, if each object has
* multiple events then each event requires a separate subscription.
* <p>
* An Event Aggregator acts as a single source of events for many objects. It registers
* for all the events of the many objects allowing clients to register with just the aggregator.
* An Event Aggregator acts as a single source of events for many objects. It registers for all the
* events of the many objects allowing clients to register with just the aggregator.
* <p>
* In the example {@link LordBaelish}, {@link LordVarys} and {@link Scout} deliver events to
* {@link KingsHand}. {@link KingsHand}, the event aggregator, then delivers the events
* to {@link KingJoffrey}.
* {@link KingsHand}. {@link KingsHand}, the event aggregator, then delivers the events to
* {@link KingJoffrey}.
*
*/
public class App {
/**
* Program entry point
* @param args command line args
*/
public static void main(String[] args) {
KingJoffrey kingJoffrey = new KingJoffrey();
KingsHand kingsHand = new KingsHand(kingJoffrey);
/**
* Program entry point
*
* @param args command line args
*/
public static void main(String[] args) {
List<EventEmitter> emitters = new ArrayList<>();
emitters.add(kingsHand);
emitters.add(new LordBaelish(kingsHand));
emitters.add(new LordVarys(kingsHand));
emitters.add(new Scout(kingsHand));
for (Weekday day: Weekday.values()) {
for (EventEmitter emitter: emitters) {
emitter.timePasses(day);
}
}
}
KingJoffrey kingJoffrey = new KingJoffrey();
KingsHand kingsHand = new KingsHand(kingJoffrey);
List<EventEmitter> emitters = new ArrayList<>();
emitters.add(kingsHand);
emitters.add(new LordBaelish(kingsHand));
emitters.add(new LordVarys(kingsHand));
emitters.add(new Scout(kingsHand));
for (Weekday day : Weekday.values()) {
for (EventEmitter emitter : emitters) {
emitter.timePasses(day);
}
}
}
}

23
event-aggregator/src/main/java/com/iluwatar/event/aggregator/Event.java
View File

@ -7,15 +7,16 @@ package com.iluwatar.event.aggregator;
*/
public enum Event {
STARK_SIGHTED("Stark sighted"), WARSHIPS_APPROACHING("Warships approaching"), TRAITOR_DETECTED("Traitor detected");
private String description;
Event(String description) {
this.description = description;
}
public String toString() {
return description;
}
STARK_SIGHTED("Stark sighted"), WARSHIPS_APPROACHING("Warships approaching"), TRAITOR_DETECTED(
"Traitor detected");
private String description;
Event(String description) {
this.description = description;
}
public String toString() {
return description;
}
}

40
event-aggregator/src/main/java/com/iluwatar/event/aggregator/EventEmitter.java
View File

@ -10,26 +10,26 @@ import java.util.List;
*/
public abstract class EventEmitter {
private List<EventObserver> observers;
private List<EventObserver> observers;
public EventEmitter() {
observers = new LinkedList<>();
}
public EventEmitter() {
observers = new LinkedList<>();
}
public EventEmitter(EventObserver obs) {
this();
registerObserver(obs);
}
public void registerObserver(EventObserver obs) {
observers.add(obs);
}
protected void notifyObservers(Event e) {
for (EventObserver obs: observers) {
obs.onEvent(e);
}
}
public abstract void timePasses(Weekday day);
public EventEmitter(EventObserver obs) {
this();
registerObserver(obs);
}
public void registerObserver(EventObserver obs) {
observers.add(obs);
}
protected void notifyObservers(Event e) {
for (EventObserver obs : observers) {
obs.onEvent(e);
}
}
public abstract void timePasses(Weekday day);
}

4
event-aggregator/src/main/java/com/iluwatar/event/aggregator/EventObserver.java
View File

@ -6,7 +6,7 @@ package com.iluwatar.event.aggregator;
*
*/
public interface EventObserver {
void onEvent(Event e);
void onEvent(Event e);
}

8
event-aggregator/src/main/java/com/iluwatar/event/aggregator/KingJoffrey.java
View File

@ -7,8 +7,8 @@ package com.iluwatar.event.aggregator;
*/
public class KingJoffrey implements EventObserver {
@Override
public void onEvent(Event e) {
System.out.println("Received event from the King's Hand: " + e.toString());
}
@Override
public void onEvent(Event e) {
System.out.println("Received event from the King's Hand: " + e.toString());
}
}

33
event-aggregator/src/main/java/com/iluwatar/event/aggregator/KingsHand.java
View File

@ -2,27 +2,26 @@ package com.iluwatar.event.aggregator;
/**
*
* KingsHand observes events from multiple sources and delivers them
* to listeners.
* KingsHand observes events from multiple sources and delivers them to listeners.
*
*/
public class KingsHand extends EventEmitter implements EventObserver {
public KingsHand() {
super();
}
public KingsHand() {
super();
}
public KingsHand(EventObserver obs) {
super(obs);
}
@Override
public void onEvent(Event e) {
notifyObservers(e);
}
public KingsHand(EventObserver obs) {
super(obs);
}
@Override
public void timePasses(Weekday day) {
// NOP
}
@Override
public void onEvent(Event e) {
notifyObservers(e);
}
@Override
public void timePasses(Weekday day) {
// NOP
}
}

28
event-aggregator/src/main/java/com/iluwatar/event/aggregator/LordBaelish.java
View File

@ -6,19 +6,19 @@ package com.iluwatar.event.aggregator;
*
*/
public class LordBaelish extends EventEmitter {
public LordBaelish() {
super();
}
public LordBaelish(EventObserver obs) {
super(obs);
}
@Override
public void timePasses(Weekday day) {
if (day.equals(Weekday.FRIDAY)) {
notifyObservers(Event.STARK_SIGHTED);
}
}
public LordBaelish() {
super();
}
public LordBaelish(EventObserver obs) {
super(obs);
}
@Override
public void timePasses(Weekday day) {
if (day.equals(Weekday.FRIDAY)) {
notifyObservers(Event.STARK_SIGHTED);
}
}
}

28
event-aggregator/src/main/java/com/iluwatar/event/aggregator/LordVarys.java
View File

@ -6,19 +6,19 @@ package com.iluwatar.event.aggregator;
*
*/
public class LordVarys extends EventEmitter {
public LordVarys() {
super();
}
public LordVarys(EventObserver obs) {
super(obs);
}
@Override
public void timePasses(Weekday day) {
if (day.equals(Weekday.SATURDAY)) {
notifyObservers(Event.TRAITOR_DETECTED);
}
}
public LordVarys() {
super();
}
public LordVarys(EventObserver obs) {
super(obs);
}
@Override
public void timePasses(Weekday day) {
if (day.equals(Weekday.SATURDAY)) {
notifyObservers(Event.TRAITOR_DETECTED);
}
}
}

28
event-aggregator/src/main/java/com/iluwatar/event/aggregator/Scout.java
View File

@ -6,19 +6,19 @@ package com.iluwatar.event.aggregator;
*
*/
public class Scout extends EventEmitter {
public Scout() {
super();
}
public Scout(EventObserver obs) {
super(obs);
}
@Override
public void timePasses(Weekday day) {
if (day.equals(Weekday.TUESDAY)) {
notifyObservers(Event.WARSHIPS_APPROACHING);
}
}
public Scout() {
super();
}
public Scout(EventObserver obs) {
super(obs);
}
@Override
public void timePasses(Weekday day) {
if (day.equals(Weekday.TUESDAY)) {
notifyObservers(Event.WARSHIPS_APPROACHING);
}
}
}

23
event-aggregator/src/main/java/com/iluwatar/event/aggregator/Weekday.java
View File

@ -6,16 +6,17 @@ package com.iluwatar.event.aggregator;
*
*/
public enum Weekday {
MONDAY("Monday"), TUESDAY("Tuesday"), WEDNESDAY("Wednesday"), THURSDAY("Thursday"), FRIDAY("Friday"), SATURDAY("Saturday"), SUNDAY("Sunday");
private String description;
Weekday(String description) {
this.description = description;
}
public String toString() {
return description;
}
MONDAY("Monday"), TUESDAY("Tuesday"), WEDNESDAY("Wednesday"), THURSDAY("Thursday"), FRIDAY(
"Friday"), SATURDAY("Saturday"), SUNDAY("Sunday");
private String description;
Weekday(String description) {
this.description = description;
}
public String toString() {
return description;
}
}

11
event-aggregator/src/test/java/com/iluwatar/event/aggregator/AppTest.java
View File

@ -1,4 +1,5 @@
package com.iluwatar.event.aggregator;
import org.junit.Test;
import com.iluwatar.event.aggregator.App;
@ -10,9 +11,9 @@ import com.iluwatar.event.aggregator.App;
*/
public class AppTest {
@Test
public void test() {
String[] args = {};
App.main(args);
}
@Test
public void test() {
String[] args = {};
App.main(args);
}
}

45
execute-around/src/main/java/com/iluwatar/execute/around/App.java
View File

@ -4,32 +4,33 @@ import java.io.FileWriter;
import java.io.IOException;
/**
* The Execute Around idiom specifies some code to be executed before and after
* a method. Typically the idiom is used when the API has methods to be executed in
* pairs, such as resource allocation/deallocation or lock acquisition/release.
* The Execute Around idiom specifies some code to be executed before and after a method. Typically
* the idiom is used when the API has methods to be executed in pairs, such as resource
* allocation/deallocation or lock acquisition/release.
* <p>
* In this example, we have {@link SimpleFileWriter} class that opens and closes the file
* for the user. The user specifies only what to do with the file by providing the
* {@link FileWriterAction} implementation.
* In this example, we have {@link SimpleFileWriter} class that opens and closes the file for the
* user. The user specifies only what to do with the file by providing the {@link FileWriterAction}
* implementation.
*
*/
public class App {
/**
* Program entry point
* @param args command line args
* @throws IOException
*/
public static void main( String[] args ) throws IOException {
new SimpleFileWriter("testfile.txt", new FileWriterAction() {
/**
* Program entry point
*
* @param args command line args
* @throws IOException
*/
public static void main(String[] args) throws IOException {
@Override
public void writeFile(FileWriter writer) throws IOException {
writer.write("Hello");
writer.append(" ");
writer.append("there!");
}
});
}
new SimpleFileWriter("testfile.txt", new FileWriterAction() {
@Override
public void writeFile(FileWriter writer) throws IOException {
writer.write("Hello");
writer.append(" ");
writer.append("there!");
}
});
}
}

4
execute-around/src/main/java/com/iluwatar/execute/around/FileWriterAction.java
View File

@ -10,6 +10,6 @@ import java.io.IOException;
*/
public interface FileWriterAction {
void writeFile(FileWriter writer) throws IOException;
void writeFile(FileWriter writer) throws IOException;
}

21
execute-around/src/main/java/com/iluwatar/execute/around/SimpleFileWriter.java
View File

@ -5,19 +5,18 @@ import java.io.IOException;
/**
*
* SimpleFileWriter handles opening and closing file for the user. The user
* only has to specify what to do with the file resource through {@link FileWriterAction}
* parameter.
* SimpleFileWriter handles opening and closing file for the user. The user only has to specify what
* to do with the file resource through {@link FileWriterAction} parameter.
*
*/
public class SimpleFileWriter {
public SimpleFileWriter(String filename, FileWriterAction action) throws IOException {
FileWriter writer = new FileWriter(filename);
try {
action.writeFile(writer);
} finally {
writer.close();
}
}
public SimpleFileWriter(String filename, FileWriterAction action) throws IOException {
FileWriter writer = new FileWriter(filename);
try {
action.writeFile(writer);
} finally {
writer.close();
}
}
}

26
execute-around/src/test/java/com/iluwatar/execute/around/AppTest.java
View File

@ -15,17 +15,17 @@ import com.iluwatar.execute.around.App;
*
*/
public class AppTest {
@Test
public void test() throws IOException {
String[] args = {};
App.main(args);
}
@Before
@After
public void cleanup() {
File file = new File("testfile.txt");
file.delete();
}
@Test
public void test() throws IOException {
String[] args = {};
App.main(args);
}
@Before
@After
public void cleanup() {
File file = new File("testfile.txt");
file.delete();
}
}

37
facade/src/main/java/com/iluwatar/facade/App.java
View File

@ -2,27 +2,28 @@ package com.iluwatar.facade;
/**
*
* The Facade design pattern is often used when a system is very complex or difficult
* to understand because the system has a large number of interdependent classes or
* its source code is unavailable. This pattern hides the complexities of the larger
* system and provides a simpler interface to the client. It typically involves a single
* wrapper class which contains a set of members required by client. These members access
* the system on behalf of the facade client and hide the implementation details.
* The Facade design pattern is often used when a system is very complex or difficult to understand
* because the system has a large number of interdependent classes or its source code is
* unavailable. This pattern hides the complexities of the larger system and provides a simpler
* interface to the client. It typically involves a single wrapper class which contains a set of
* members required by client. These members access the system on behalf of the facade client and
* hide the implementation details.
* <p>
* In this example the Facade is ({@link DwarvenGoldmineFacade}) and it provides a simpler
* interface to the goldmine subsystem.
* In this example the Facade is ({@link DwarvenGoldmineFacade}) and it provides a simpler interface
* to the goldmine subsystem.
*
*/
public class App {
/**
* Program entry point
* @param args command line args
*/
public static void main(String[] args) {
DwarvenGoldmineFacade facade = new DwarvenGoldmineFacade();
facade.startNewDay();
facade.digOutGold();
facade.endDay();
}
/**
* Program entry point
*
* @param args command line args
*/
public static void main(String[] args) {
DwarvenGoldmineFacade facade = new DwarvenGoldmineFacade();
facade.startNewDay();
facade.digOutGold();
facade.endDay();
}
}

17
facade/src/main/java/com/iluwatar/facade/DwarvenCartOperator.java
View File

@ -7,14 +7,13 @@ package com.iluwatar.facade;
*/
public class DwarvenCartOperator extends DwarvenMineWorker {
@Override
public void work() {
System.out.println(name() + " moves gold chunks out of the mine.");
}
@Override
public String name() {
return "Dwarf cart operator";
}
@Override
public void work() {
System.out.println(name() + " moves gold chunks out of the mine.");
}
@Override
public String name() {
return "Dwarf cart operator";
}
}

17
facade/src/main/java/com/iluwatar/facade/DwarvenGoldDigger.java
View File

@ -7,14 +7,13 @@ package com.iluwatar.facade;
*/
public class DwarvenGoldDigger extends DwarvenMineWorker {
@Override
public void work() {
System.out.println(name() + " digs for gold.");
}
@Override
public String name() {
return "Dwarf gold digger";
}
@Override
public void work() {
System.out.println(name() + " digs for gold.");
}
@Override
public String name() {
return "Dwarf gold digger";
}
}

49
facade/src/main/java/com/iluwatar/facade/DwarvenGoldmineFacade.java
View File

@ -6,40 +6,39 @@ import java.util.List;
/**
*
* DwarvenGoldmineFacade provides a single interface
* through which users can operate the subsystems.
* DwarvenGoldmineFacade provides a single interface through which users can operate the subsystems.
*
* This makes the goldmine easier to operate and
* cuts the dependencies from the goldmine user to
* the subsystems.
* This makes the goldmine easier to operate and cuts the dependencies from the goldmine user to the
* subsystems.
*
*/
public class DwarvenGoldmineFacade {
private final List<DwarvenMineWorker> workers;
private final List<DwarvenMineWorker> workers;
public DwarvenGoldmineFacade() {
workers = new ArrayList<>();
workers.add(new DwarvenGoldDigger());
workers.add(new DwarvenCartOperator());
workers.add(new DwarvenTunnelDigger());
}
public DwarvenGoldmineFacade() {
workers = new ArrayList<>();
workers.add(new DwarvenGoldDigger());
workers.add(new DwarvenCartOperator());
workers.add(new DwarvenTunnelDigger());
}
public void startNewDay() {
makeActions(workers, DwarvenMineWorker.Action.WAKE_UP, DwarvenMineWorker.Action.GO_TO_MINE);
}
public void startNewDay() {
makeActions(workers, DwarvenMineWorker.Action.WAKE_UP, DwarvenMineWorker.Action.GO_TO_MINE);
}
public void digOutGold() {
makeActions(workers, DwarvenMineWorker.Action.WORK);
}
public void digOutGold() {
makeActions(workers, DwarvenMineWorker.Action.WORK);
}
public void endDay() {
makeActions(workers, DwarvenMineWorker.Action.GO_HOME, DwarvenMineWorker.Action.GO_TO_SLEEP);
}
public void endDay() {
makeActions(workers, DwarvenMineWorker.Action.GO_HOME, DwarvenMineWorker.Action.GO_TO_SLEEP);
}
private void makeActions(Collection<DwarvenMineWorker> workers, DwarvenMineWorker.Action... actions) {
for (DwarvenMineWorker worker : workers) {
worker.action(actions);
}
private void makeActions(Collection<DwarvenMineWorker> workers,
DwarvenMineWorker.Action... actions) {
for (DwarvenMineWorker worker : workers) {
worker.action(actions);
}
}
}

84
facade/src/main/java/com/iluwatar/facade/DwarvenMineWorker.java
View File

@ -7,56 +7,56 @@ package com.iluwatar.facade;
*/
public abstract class DwarvenMineWorker {
public void goToSleep() {
System.out.println(name() + " goes to sleep.");
}
public void goToSleep() {
System.out.println(name() + " goes to sleep.");
}
public void wakeUp() {
System.out.println(name() + " wakes up.");
}
public void wakeUp() {
System.out.println(name() + " wakes up.");
}
public void goHome() {
System.out.println(name() + " goes home.");
}
public void goHome() {
System.out.println(name() + " goes home.");
}
public void goToMine() {
System.out.println(name() + " goes to the mine.");
}
public void goToMine() {
System.out.println(name() + " goes to the mine.");
}
private void action(Action action) {
switch (action) {
case GO_TO_SLEEP:
goToSleep();
break;
case WAKE_UP:
wakeUp();
break;
case GO_HOME:
goHome();
break;
case GO_TO_MINE:
goToMine();
break;
case WORK:
work();
break;
default:
System.out.println("Undefined action");
break;
}
private void action(Action action) {
switch (action) {
case GO_TO_SLEEP:
goToSleep();
break;
case WAKE_UP:
wakeUp();
break;
case GO_HOME:
goHome();
break;
case GO_TO_MINE:
goToMine();
break;
case WORK:
work();
break;
default:
System.out.println("Undefined action");
break;
}
}
public void action(Action... actions) {
for (Action action : actions) {
action(action);
}
public void action(Action... actions) {
for (Action action : actions) {
action(action);
}
}
public abstract void work();
public abstract void work();
public abstract String name();
public abstract String name();
static enum Action {
GO_TO_SLEEP, WAKE_UP, GO_HOME, GO_TO_MINE, WORK
}
static enum Action {
GO_TO_SLEEP, WAKE_UP, GO_HOME, GO_TO_MINE, WORK
}
}

17
facade/src/main/java/com/iluwatar/facade/DwarvenTunnelDigger.java
View File

@ -7,14 +7,13 @@ package com.iluwatar.facade;
*/
public class DwarvenTunnelDigger extends DwarvenMineWorker {
@Override
public void work() {
System.out.println(name() + " creates another promising tunnel.");
}
@Override
public String name() {
return "Dwarven tunnel digger";
}
@Override
public void work() {
System.out.println(name() + " creates another promising tunnel.");
}
@Override
public String name() {
return "Dwarven tunnel digger";
}
}

10
facade/src/test/java/com/iluwatar/facade/AppTest.java
View File

@ -11,9 +11,9 @@ import com.iluwatar.facade.App;
*/
public class AppTest {
@Test
public void test() {
String[] args = {};
App.main(args);
}
@Test
public void test() {
String[] args = {};
App.main(args);
}
}

54
factory-method/src/main/java/com/iluwatar/factory/method/App.java
View File

@ -2,39 +2,39 @@ package com.iluwatar.factory.method;
/**
*
* The Factory Method is a creational design pattern which uses factory methods to deal
* with the problem of creating objects without specifying the exact class of object
* that will be created. This is done by creating objects via calling a factory
* method either specified in an interface and implemented by child classes, or implemented
* in a base class and optionally overridden by derived classes—rather than by calling a
* constructor.
* The Factory Method is a creational design pattern which uses factory methods to deal with the
* problem of creating objects without specifying the exact class of object that will be created.
* This is done by creating objects via calling a factory method either specified in an interface
* and implemented by child classes, or implemented in a base class and optionally overridden by
* derived classes—rather than by calling a constructor.
* <p>
* In this Factory Method example we have an interface ({@link Blacksmith}) with a method for
* creating objects ({@link Blacksmith#manufactureWeapon}). The concrete subclasses
* ({@link OrcBlacksmith}, {@link ElfBlacksmith}) then override the method to produce
* objects of their liking.
* creating objects ({@link Blacksmith#manufactureWeapon}). The concrete subclasses (
* {@link OrcBlacksmith}, {@link ElfBlacksmith}) then override the method to produce objects of
* their liking.
*
*/
public class App {
/**
* Program entry point
* @param args command line args
*/
public static void main(String[] args) {
Blacksmith blacksmith;
Weapon weapon;
/**
* Program entry point
*
* @param args command line args
*/
public static void main(String[] args) {
Blacksmith blacksmith;
Weapon weapon;
blacksmith = new OrcBlacksmith();
weapon = blacksmith.manufactureWeapon(WeaponType.SPEAR);
System.out.println(weapon);
weapon = blacksmith.manufactureWeapon(WeaponType.AXE);
System.out.println(weapon);
blacksmith = new OrcBlacksmith();
weapon = blacksmith.manufactureWeapon(WeaponType.SPEAR);
System.out.println(weapon);
weapon = blacksmith.manufactureWeapon(WeaponType.AXE);
System.out.println(weapon);
blacksmith = new ElfBlacksmith();
weapon = blacksmith.manufactureWeapon(WeaponType.SHORT_SWORD);
System.out.println(weapon);
weapon = blacksmith.manufactureWeapon(WeaponType.SPEAR);
System.out.println(weapon);
}
blacksmith = new ElfBlacksmith();
weapon = blacksmith.manufactureWeapon(WeaponType.SHORT_SWORD);
System.out.println(weapon);
weapon = blacksmith.manufactureWeapon(WeaponType.SPEAR);
System.out.println(weapon);
}
}

2
factory-method/src/main/java/com/iluwatar/factory/method/Blacksmith.java
View File

@ -7,6 +7,6 @@ package com.iluwatar.factory.method;
*/
public interface Blacksmith {
Weapon manufactureWeapon(WeaponType weaponType);
Weapon manufactureWeapon(WeaponType weaponType);
}

6
factory-method/src/main/java/com/iluwatar/factory/method/ElfBlacksmith.java
View File

@ -7,8 +7,8 @@ package com.iluwatar.factory.method;
*/
public class ElfBlacksmith implements Blacksmith {
public Weapon manufactureWeapon(WeaponType weaponType) {
return new ElfWeapon(weaponType);
}
public Weapon manufactureWeapon(WeaponType weaponType) {
return new ElfWeapon(weaponType);
}
}

17
factory-method/src/main/java/com/iluwatar/factory/method/ElfWeapon.java
View File

@ -7,15 +7,14 @@ package com.iluwatar.factory.method;
*/
public class ElfWeapon implements Weapon {
private WeaponType weaponType;
private WeaponType weaponType;
public ElfWeapon(WeaponType weaponType) {
this.weaponType = weaponType;
}
@Override
public String toString() {
return "Elven " + weaponType;
}
public ElfWeapon(WeaponType weaponType) {
this.weaponType = weaponType;
}
@Override
public String toString() {
return "Elven " + weaponType;
}
}

7
factory-method/src/main/java/com/iluwatar/factory/method/OrcBlacksmith.java
View File

@ -7,8 +7,7 @@ package com.iluwatar.factory.method;
*/
public class OrcBlacksmith implements Blacksmith {
public Weapon manufactureWeapon(WeaponType weaponType) {
return new OrcWeapon(weaponType);
}
public Weapon manufactureWeapon(WeaponType weaponType) {
return new OrcWeapon(weaponType);
}
}

17
factory-method/src/main/java/com/iluwatar/factory/method/OrcWeapon.java
View File

@ -7,15 +7,14 @@ package com.iluwatar.factory.method;
*/
public class OrcWeapon implements Weapon {
private WeaponType weaponType;
private WeaponType weaponType;
public OrcWeapon(WeaponType weaponType) {
this.weaponType = weaponType;
}
@Override
public String toString() {
return "Orcish " + weaponType;
}
public OrcWeapon(WeaponType weaponType) {
this.weaponType = weaponType;
}
@Override
public String toString() {
return "Orcish " + weaponType;
}
}

18
factory-method/src/main/java/com/iluwatar/factory/method/WeaponType.java
View File

@ -7,16 +7,16 @@ package com.iluwatar.factory.method;
*/
public enum WeaponType {
SHORT_SWORD("short sword"), SPEAR("spear"), AXE("axe"), UNDEFINED("");
SHORT_SWORD("short sword"), SPEAR("spear"), AXE("axe"), UNDEFINED("");
private String title;
private String title;
WeaponType(String title) {
this.title = title;
}
WeaponType(String title) {
this.title = title;
}
@Override
public String toString() {
return title;
}
@Override
public String toString() {
return title;
}
}

10
factory-method/src/test/java/com/iluwatar/factory/method/AppTest.java
View File

@ -11,9 +11,9 @@ import com.iluwatar.factory.method.App;
*/
public class AppTest {
@Test
public void test() {
String[] args = {};
App.main(args);
}
@Test
public void test() {
String[] args = {};
App.main(args);
}
}

20
fluentinterface/src/main/java/com/iluwatar/fluentinterface/app/App.java
View File

@ -11,13 +11,15 @@ import java.util.function.Predicate;
import static java.lang.String.valueOf;
/**
* The Fluent Interface pattern is useful when you want to provide an easy readable, flowing API. Those
* interfaces tend to mimic domain specific languages, so they can nearly be read as human languages.
* The Fluent Interface pattern is useful when you want to provide an easy readable, flowing API.
* Those interfaces tend to mimic domain specific languages, so they can nearly be read as human
* languages.
* <p>
* In this example two implementations of a {@link FluentIterable} interface are given. The
* {@link SimpleFluentIterable} evaluates eagerly and would be too costly for real world applications.
* The {@link LazyFluentIterable} is evaluated on termination. Their usage is demonstrated with a
* simple number list that is filtered, transformed and collected. The result is printed afterwards.
* {@link SimpleFluentIterable} evaluates eagerly and would be too costly for real world
* applications. The {@link LazyFluentIterable} is evaluated on termination. Their usage is
* demonstrated with a simple number list that is filtered, transformed and collected. The result is
* printed afterwards.
*
*/
public class App {
@ -25,11 +27,9 @@ public class App {
public static void main(String[] args) {
List<Integer> integerList = new ArrayList<>();
integerList.addAll(Arrays.asList(
1, -61, 14, -22, 18, -87, 6, 64, -82, 26, -98, 97,
45, 23, 2, -68, 45
));
integerList.addAll(Arrays.asList(1, -61, 14, -22, 18, -87, 6, 64, -82, 26, -98, 97, 45, 23, 2,
-68, 45));
prettyPrint("The initial list contains: ", integerList);
List<Integer> firstFiveNegatives =

18
flux/src/main/java/com/iluwatar/flux/action/Action.java
View File

@ -7,13 +7,13 @@ package com.iluwatar.flux.action;
*/
public abstract class Action {
private ActionType type;
public Action(ActionType type) {
this.type = type;
}
public ActionType getType() {
return type;
}
private ActionType type;
public Action(ActionType type) {
this.type = type;
}
public ActionType getType() {
return type;
}
}

4
flux/src/main/java/com/iluwatar/flux/action/ActionType.java
View File

@ -7,6 +7,6 @@ package com.iluwatar.flux.action;
*/
public enum ActionType {
MENU_ITEM_SELECTED, CONTENT_CHANGED;
MENU_ITEM_SELECTED, CONTENT_CHANGED;
}

25
flux/src/main/java/com/iluwatar/flux/action/Content.java
View File

@ -6,17 +6,18 @@ package com.iluwatar.flux.action;
*
*/
public enum Content {
PRODUCTS("Products - This page lists the company's products."), COMPANY("Company - This page displays information about the company.");
private String title;
private Content(String title) {
this.title = title;
}
@Override
public String toString() {
return title;
}
PRODUCTS("Products - This page lists the company's products."), COMPANY(
"Company - This page displays information about the company.");
private String title;
private Content(String title) {
this.title = title;
}
@Override
public String toString() {
return title;
}
}

18
flux/src/main/java/com/iluwatar/flux/action/ContentAction.java
View File

@ -7,14 +7,14 @@ package com.iluwatar.flux.action;
*/
public class ContentAction extends Action {
private Content content;
private Content content;
public ContentAction(Content content) {
super(ActionType.CONTENT_CHANGED);
this.content = content;
}
public Content getContent() {
return content;
}
public ContentAction(Content content) {
super(ActionType.CONTENT_CHANGED);
this.content = content;
}
public Content getContent() {
return content;
}
}

18
flux/src/main/java/com/iluwatar/flux/action/MenuAction.java
View File

@ -8,14 +8,14 @@ package com.iluwatar.flux.action;
*/
public class MenuAction extends Action {
private MenuItem menuItem;
private MenuItem menuItem;
public MenuAction(MenuItem menuItem) {
super(ActionType.MENU_ITEM_SELECTED);
this.menuItem = menuItem;
}
public MenuItem getMenuItem() {
return menuItem;
}
public MenuAction(MenuItem menuItem) {
super(ActionType.MENU_ITEM_SELECTED);
this.menuItem = menuItem;
}
public MenuItem getMenuItem() {
return menuItem;
}
}

24
flux/src/main/java/com/iluwatar/flux/action/MenuItem.java
View File

@ -6,17 +6,17 @@ package com.iluwatar.flux.action;
*
*/
public enum MenuItem {
HOME("Home"), PRODUCTS("Products"), COMPANY("Company");
private String title;
MenuItem(String title) {
this.title = title;
}
@Override
public String toString() {
return title;
}
HOME("Home"), PRODUCTS("Products"), COMPANY("Company");
private String title;
MenuItem(String title) {
this.title = title;
}
@Override
public String toString() {
return title;
}
}

68
flux/src/main/java/com/iluwatar/flux/app/App.java
View File

@ -9,43 +9,45 @@ import com.iluwatar.flux.view.MenuView;
/**
*
* Flux is the application architecture that Facebook uses for building client-side web
* applications. Flux eschews MVC in favor of a unidirectional data flow. When a user interacts with
* a React view, the view propagates an action through a central dispatcher, to the various stores that
* hold the application's data and business logic, which updates all of the views that are affected.
* Flux is the application architecture that Facebook uses for building client-side web
* applications. Flux eschews MVC in favor of a unidirectional data flow. When a user interacts with
* a React view, the view propagates an action through a central dispatcher, to the various stores
* that hold the application's data and business logic, which updates all of the views that are
* affected.
* <p>
* This example has two views: menu and content. They represent typical main menu and content area of
* a web page. When menu item is clicked it triggers events through the dispatcher. The events are
* received and handled by the stores updating their data as needed. The stores then notify the views
* that they should rerender themselves.
* This example has two views: menu and content. They represent typical main menu and content area
* of a web page. When menu item is clicked it triggers events through the dispatcher. The events
* are received and handled by the stores updating their data as needed. The stores then notify the
* views that they should rerender themselves.
* <p>
* http://facebook.github.io/flux/docs/overview.html
*
*/
public class App {
/**
* Program entry point
* @param args command line args
*/
public static void main( String[] args ) {
// initialize and wire the system
MenuStore menuStore = new MenuStore();
Dispatcher.getInstance().registerStore(menuStore);
ContentStore contentStore = new ContentStore();
Dispatcher.getInstance().registerStore(contentStore);
MenuView menuView = new MenuView();
menuStore.registerView(menuView);
ContentView contentView = new ContentView();
contentStore.registerView(contentView);
// render initial view
menuView.render();
contentView.render();
// user clicks another menu item
// this triggers action dispatching and eventually causes views to render with new content
menuView.itemClicked(MenuItem.COMPANY);
}
/**
* Program entry point
*
* @param args command line args
*/
public static void main(String[] args) {
// initialize and wire the system
MenuStore menuStore = new MenuStore();
Dispatcher.getInstance().registerStore(menuStore);
ContentStore contentStore = new ContentStore();
Dispatcher.getInstance().registerStore(contentStore);
MenuView menuView = new MenuView();
menuStore.registerView(menuView);
ContentView contentView = new ContentView();
contentStore.registerView(contentView);
// render initial view
menuView.render();
contentView.render();
// user clicks another menu item
// this triggers action dispatching and eventually causes views to render with new content
menuView.itemClicked(MenuItem.COMPANY);
}
}

63
flux/src/main/java/com/iluwatar/flux/dispatcher/Dispatcher.java
View File

@ -16,37 +16,36 @@ import com.iluwatar.flux.store.Store;
*
*/
public class Dispatcher {
private static Dispatcher instance = new Dispatcher();
private List<Store> stores = new LinkedList<>();
private Dispatcher() {
}
public static Dispatcher getInstance() {
return instance;
}
public void registerStore(Store store) {
stores.add(store);
}
public void menuItemSelected(MenuItem menuItem) {
dispatchAction(new MenuAction(menuItem));
switch (menuItem) {
case HOME:
case PRODUCTS:
default:
dispatchAction(new ContentAction(Content.PRODUCTS));
break;
case COMPANY:
dispatchAction(new ContentAction(Content.COMPANY));
break;
}
}
private void dispatchAction(Action action) {
stores.stream().forEach((store) -> store.onAction(action));
}
private static Dispatcher instance = new Dispatcher();
private List<Store> stores = new LinkedList<>();
private Dispatcher() {}
public static Dispatcher getInstance() {
return instance;
}
public void registerStore(Store store) {
stores.add(store);
}
public void menuItemSelected(MenuItem menuItem) {
dispatchAction(new MenuAction(menuItem));
switch (menuItem) {
case HOME:
case PRODUCTS:
default:
dispatchAction(new ContentAction(Content.PRODUCTS));
break;
case COMPANY:
dispatchAction(new ContentAction(Content.COMPANY));
break;
}
}
private void dispatchAction(Action action) {
stores.stream().forEach((store) -> store.onAction(action));
}
}

26
flux/src/main/java/com/iluwatar/flux/store/ContentStore.java
View File

@ -12,18 +12,18 @@ import com.iluwatar.flux.action.ContentAction;
*/
public class ContentStore extends Store {
private Content content = Content.PRODUCTS;
private Content content = Content.PRODUCTS;
@Override
public void onAction(Action action) {
if (action.getType().equals(ActionType.CONTENT_CHANGED)) {
ContentAction contentAction = (ContentAction) action;
content = contentAction.getContent();
notifyChange();
}
}
public Content getContent() {
return content;
}
@Override
public void onAction(Action action) {
if (action.getType().equals(ActionType.CONTENT_CHANGED)) {
ContentAction contentAction = (ContentAction) action;
content = contentAction.getContent();
notifyChange();
}
}
public Content getContent() {
return content;
}
}

28
flux/src/main/java/com/iluwatar/flux/store/MenuStore.java
View File

@ -12,18 +12,18 @@ import com.iluwatar.flux.action.MenuItem;
*/
public class MenuStore extends Store {
private MenuItem selected = MenuItem.HOME;
@Override
public void onAction(Action action) {
if (action.getType().equals(ActionType.MENU_ITEM_SELECTED)) {
MenuAction menuAction = (MenuAction) action;
selected = menuAction.getMenuItem();
notifyChange();
}
}
public MenuItem getSelected() {
return selected;
}
private MenuItem selected = MenuItem.HOME;
@Override
public void onAction(Action action) {
if (action.getType().equals(ActionType.MENU_ITEM_SELECTED)) {
MenuAction menuAction = (MenuAction) action;
selected = menuAction.getMenuItem();
notifyChange();
}
}
public MenuItem getSelected() {
return selected;
}
}

22
flux/src/main/java/com/iluwatar/flux/store/Store.java
View File

@ -12,16 +12,16 @@ import com.iluwatar.flux.view.View;
*
*/
public abstract class Store {
private List<View> views = new LinkedList<>();
public abstract void onAction(Action action);
public void registerView(View view) {
views.add(view);
}
protected void notifyChange() {
views.stream().forEach((view) -> view.storeChanged(this));
}
private List<View> views = new LinkedList<>();
public abstract void onAction(Action action);
public void registerView(View view) {
views.add(view);
}
protected void notifyChange() {
views.stream().forEach((view) -> view.storeChanged(this));
}
}

22
flux/src/main/java/com/iluwatar/flux/view/ContentView.java
View File

@ -11,17 +11,17 @@ import com.iluwatar.flux.store.Store;
*/
public class ContentView implements View {
private Content content = Content.PRODUCTS;
private Content content = Content.PRODUCTS;
@Override
public void storeChanged(Store store) {
ContentStore contentStore = (ContentStore) store;
content = contentStore.getContent();
render();
}
@Override
public void storeChanged(Store store) {
ContentStore contentStore = (ContentStore) store;
content = contentStore.getContent();
render();
}
@Override
public void render() {
System.out.println(content.toString());
}
@Override
public void render() {
System.out.println(content.toString());
}
}

44
flux/src/main/java/com/iluwatar/flux/view/MenuView.java
View File

@ -12,27 +12,27 @@ import com.iluwatar.flux.store.Store;
*/
public class MenuView implements View {
private MenuItem selected = MenuItem.HOME;
@Override
public void storeChanged(Store store) {
MenuStore menuStore = (MenuStore) store;
selected = menuStore.getSelected();
render();
}
private MenuItem selected = MenuItem.HOME;
@Override
public void render() {
for (MenuItem item: MenuItem.values()) {
if (selected.equals(item)) {
System.out.println(String.format("* %s", item.toString()));
} else {
System.out.println(item.toString());
}
}
}
public void itemClicked(MenuItem item) {
Dispatcher.getInstance().menuItemSelected(item);
}
@Override
public void storeChanged(Store store) {
MenuStore menuStore = (MenuStore) store;
selected = menuStore.getSelected();
render();
}
@Override
public void render() {
for (MenuItem item : MenuItem.values()) {
if (selected.equals(item)) {
System.out.println(String.format("* %s", item.toString()));
} else {
System.out.println(item.toString());
}
}
}
public void itemClicked(MenuItem item) {
Dispatcher.getInstance().menuItemSelected(item);
}
}

4
flux/src/main/java/com/iluwatar/flux/view/View.java
View File

@ -9,7 +9,7 @@ import com.iluwatar.flux.store.Store;
*/
public interface View {
public void storeChanged(Store store);
public void storeChanged(Store store);
public void render();
public void render();
}

12
flux/src/test/java/com/iluwatar/flux/app/AppTest.java
View File

@ -10,10 +10,10 @@ import com.iluwatar.flux.app.App;
*
*/
public class AppTest {
@Test
public void test() {
String[] args = {};
App.main(args);
}
@Test
public void test() {
String[] args = {};
App.main(args);
}
}

69
flyweight/src/main/java/com/iluwatar/flyweight/AlchemistShop.java
View File

@ -5,53 +5,52 @@ import java.util.List;
/**
*
* AlchemistShop holds potions on its shelves.
* It uses PotionFactory to provide the potions.
* AlchemistShop holds potions on its shelves. It uses PotionFactory to provide the potions.
*
*/
public class AlchemistShop {
private List<Potion> topShelf;
private List<Potion> bottomShelf;
private List<Potion> topShelf;
private List<Potion> bottomShelf;
public AlchemistShop() {
topShelf = new ArrayList<>();
bottomShelf = new ArrayList<>();
fillShelves();
}
public AlchemistShop() {
topShelf = new ArrayList<>();
bottomShelf = new ArrayList<>();
fillShelves();
}
private void fillShelves() {
private void fillShelves() {
PotionFactory factory = new PotionFactory();
PotionFactory factory = new PotionFactory();
topShelf.add(factory.createPotion(PotionType.INVISIBILITY));
topShelf.add(factory.createPotion(PotionType.INVISIBILITY));
topShelf.add(factory.createPotion(PotionType.STRENGTH));
topShelf.add(factory.createPotion(PotionType.HEALING));
topShelf.add(factory.createPotion(PotionType.INVISIBILITY));
topShelf.add(factory.createPotion(PotionType.STRENGTH));
topShelf.add(factory.createPotion(PotionType.HEALING));
topShelf.add(factory.createPotion(PotionType.HEALING));
topShelf.add(factory.createPotion(PotionType.INVISIBILITY));
topShelf.add(factory.createPotion(PotionType.INVISIBILITY));
topShelf.add(factory.createPotion(PotionType.STRENGTH));
topShelf.add(factory.createPotion(PotionType.HEALING));
topShelf.add(factory.createPotion(PotionType.INVISIBILITY));
topShelf.add(factory.createPotion(PotionType.STRENGTH));
topShelf.add(factory.createPotion(PotionType.HEALING));
topShelf.add(factory.createPotion(PotionType.HEALING));
bottomShelf.add(factory.createPotion(PotionType.POISON));
bottomShelf.add(factory.createPotion(PotionType.POISON));
bottomShelf.add(factory.createPotion(PotionType.POISON));
bottomShelf.add(factory.createPotion(PotionType.HOLY_WATER));
bottomShelf.add(factory.createPotion(PotionType.HOLY_WATER));
}
bottomShelf.add(factory.createPotion(PotionType.POISON));
bottomShelf.add(factory.createPotion(PotionType.POISON));
bottomShelf.add(factory.createPotion(PotionType.POISON));
bottomShelf.add(factory.createPotion(PotionType.HOLY_WATER));
bottomShelf.add(factory.createPotion(PotionType.HOLY_WATER));
}
public void enumerate() {
public void enumerate() {
System.out.println("Enumerating top shelf potions\n");
System.out.println("Enumerating top shelf potions\n");
for (Potion p : topShelf) {
p.drink();
}
for (Potion p : topShelf) {
p.drink();
}
System.out.println("\nEnumerating bottom shelf potions\n");
System.out.println("\nEnumerating bottom shelf potions\n");
for (Potion p : bottomShelf) {
p.drink();
}
}
for (Potion p : bottomShelf) {
p.drink();
}
}
}

33
flyweight/src/main/java/com/iluwatar/flyweight/App.java
View File

@ -2,26 +2,27 @@ package com.iluwatar.flyweight;
/**
*
* Flyweight pattern is useful when the program needs a huge amount of objects.
* It provides means to decrease resource usage by sharing object instances.
* Flyweight pattern is useful when the program needs a huge amount of objects. It provides means to
* decrease resource usage by sharing object instances.
* <p>
* In this example {@link AlchemistShop} has great amount of potions on its shelves.
* To fill the shelves {@link AlchemistShop} uses {@link PotionFactory} (which represents
* the Flyweight in this example). Internally {@link PotionFactory} holds a map
* of the potions and lazily creates new ones when requested.
* In this example {@link AlchemistShop} has great amount of potions on its shelves. To fill the
* shelves {@link AlchemistShop} uses {@link PotionFactory} (which represents the Flyweight in this
* example). Internally {@link PotionFactory} holds a map of the potions and lazily creates new ones
* when requested.
* <p>
* To enable safe sharing, between clients and threads, Flyweight objects must
* be immutable. Flyweight objects are by definition value objects.
* To enable safe sharing, between clients and threads, Flyweight objects must be immutable.
* Flyweight objects are by definition value objects.
*
*/
public class App {
/**
* Program entry point
* @param args command line args
*/
public static void main(String[] args) {
AlchemistShop alchemistShop = new AlchemistShop();
alchemistShop.enumerate();
}
/**
* Program entry point
*
* @param args command line args
*/
public static void main(String[] args) {
AlchemistShop alchemistShop = new AlchemistShop();
alchemistShop.enumerate();
}
}

10
flyweight/src/main/java/com/iluwatar/flyweight/HealingPotion.java
View File

@ -7,10 +7,8 @@ package com.iluwatar.flyweight;
*/
public class HealingPotion implements Potion {
@Override
public void drink() {
System.out.println("You feel healed. (Potion="
+ System.identityHashCode(this) + ")");
}
@Override
public void drink() {
System.out.println("You feel healed. (Potion=" + System.identityHashCode(this) + ")");
}
}

10
flyweight/src/main/java/com/iluwatar/flyweight/HolyWaterPotion.java
View File

@ -7,10 +7,8 @@ package com.iluwatar.flyweight;
*/
public class HolyWaterPotion implements Potion {
@Override
public void drink() {
System.out.println("You feel blessed. (Potion="
+ System.identityHashCode(this) + ")");
}
@Override
public void drink() {
System.out.println("You feel blessed. (Potion=" + System.identityHashCode(this) + ")");
}
}

10
flyweight/src/main/java/com/iluwatar/flyweight/InvisibilityPotion.java
View File

@ -7,10 +7,8 @@ package com.iluwatar.flyweight;
*/
public class InvisibilityPotion implements Potion {
@Override
public void drink() {
System.out.println("You become invisible. (Potion="
+ System.identityHashCode(this) + ")");
}
@Override
public void drink() {
System.out.println("You become invisible. (Potion=" + System.identityHashCode(this) + ")");
}
}

10
flyweight/src/main/java/com/iluwatar/flyweight/PoisonPotion.java
View File

@ -7,10 +7,8 @@ package com.iluwatar.flyweight;
*/
public class PoisonPotion implements Potion {
@Override
public void drink() {
System.out.println("Urgh! This is poisonous. (Potion="
+ System.identityHashCode(this) + ")");
}
@Override
public void drink() {
System.out.println("Urgh! This is poisonous. (Potion=" + System.identityHashCode(this) + ")");
}
}

2
flyweight/src/main/java/com/iluwatar/flyweight/Potion.java
View File

@ -7,5 +7,5 @@ package com.iluwatar.flyweight;
*/
public interface Potion {
void drink();
void drink();
}

75
flyweight/src/main/java/com/iluwatar/flyweight/PotionFactory.java
View File

@ -5,48 +5,47 @@ import java.util.Map;
/**
*
* PotionFactory is the Flyweight in this example.
* It minimizes memory use by sharing object instances.
* It holds a map of potion instances and new potions
* are created only when none of the type already exists.
* PotionFactory is the Flyweight in this example. It minimizes memory use by sharing object
* instances. It holds a map of potion instances and new potions are created only when none of the
* type already exists.
*
*/
public class PotionFactory {
private final Map<PotionType, Potion> potions;
private final Map<PotionType, Potion> potions;
public PotionFactory() {
potions = new EnumMap<>(PotionType.class);
}
public PotionFactory() {
potions = new EnumMap<>(PotionType.class);
}
Potion createPotion(PotionType type) {
Potion potion = potions.get(type);
if (potion == null) {
switch (type) {
case HEALING:
potion = new HealingPotion();
potions.put(type, potion);
break;
case HOLY_WATER:
potion = new HolyWaterPotion();
potions.put(type, potion);
break;
case INVISIBILITY:
potion = new InvisibilityPotion();
potions.put(type, potion);
break;
case POISON:
potion = new PoisonPotion();
potions.put(type, potion);
break;
case STRENGTH:
potion = new StrengthPotion();
potions.put(type, potion);
break;
default:
break;
}
}
return potion;
}
Potion createPotion(PotionType type) {
Potion potion = potions.get(type);
if (potion == null) {
switch (type) {
case HEALING:
potion = new HealingPotion();
potions.put(type, potion);
break;
case HOLY_WATER:
potion = new HolyWaterPotion();
potions.put(type, potion);
break;
case INVISIBILITY:
potion = new InvisibilityPotion();
potions.put(type, potion);
break;
case POISON:
potion = new PoisonPotion();
potions.put(type, potion);
break;
case STRENGTH:
potion = new StrengthPotion();
potions.put(type, potion);
break;
default:
break;
}
}
return potion;
}
}

2
flyweight/src/main/java/com/iluwatar/flyweight/PotionType.java
View File

@ -7,5 +7,5 @@ package com.iluwatar.flyweight;
*/
public enum PotionType {
HEALING, INVISIBILITY, STRENGTH, HOLY_WATER, POISON
HEALING, INVISIBILITY, STRENGTH, HOLY_WATER, POISON
}

9
flyweight/src/main/java/com/iluwatar/flyweight/StrengthPotion.java
View File

@ -7,9 +7,8 @@ package com.iluwatar.flyweight;
*/
public class StrengthPotion implements Potion {
@Override
public void drink() {
System.out.println("You feel strong. (Potion="
+ System.identityHashCode(this) + ")");
}
@Override
public void drink() {
System.out.println("You feel strong. (Potion=" + System.identityHashCode(this) + ")");
}
}

10
flyweight/src/test/java/com/iluwatar/flyweight/AppTest.java
View File

@ -11,9 +11,9 @@ import com.iluwatar.flyweight.App;
*/
public class AppTest {
@Test
public void test() {
String[] args = {};
App.main(args);
}
@Test
public void test() {
String[] args = {};
App.main(args);
}
}

204
half-sync-half-async/src/main/java/com/iluwatar/halfsynchalfasync/App.java
View File

@ -8,122 +8,120 @@ import java.util.concurrent.LinkedBlockingQueue;
* {@link AsyncTask} and {@link AsynchronousService}.
*
* <p>
* <i>PROBLEM</i>
* <br/>
* A concurrent system have a mixture of short duration, mid duration and long duration tasks.
* Mid or long duration tasks should be performed asynchronously to meet quality of service
* <i>PROBLEM</i> <br/>
* A concurrent system have a mixture of short duration, mid duration and long duration tasks. Mid
* or long duration tasks should be performed asynchronously to meet quality of service
* requirements.
*
* <p><i>INTENT</i>
* <br/>
* The intent of this pattern is to separate the the synchronous and asynchronous processing
* in the concurrent application by introducing two intercommunicating layers - one for sync
* and one for async. This simplifies the programming without unduly affecting the performance.
*
*
* <p>
* <i>APPLICABILITY</i>
* <br/>
* <i>INTENT</i> <br/>
* The intent of this pattern is to separate the the synchronous and asynchronous processing in the
* concurrent application by introducing two intercommunicating layers - one for sync and one for
* async. This simplifies the programming without unduly affecting the performance.
*
* <p>
* <i>APPLICABILITY</i> <br/>
* <ul>
* <li>UNIX network subsystems - In operating systems network operations are carried out
* asynchronously with help of hardware level interrupts.</li>
* <li>CORBA - At the asynchronous layer one thread is associated with each socket that is
* connected to the client. Thread blocks waiting for CORBA requests from the client. On receiving
* request it is inserted in the queuing layer which is then picked up by synchronous layer which
* processes the request and sends response back to the client.</li>
* <li>Android AsyncTask framework - Framework provides a way to execute long running blocking calls,
* such as downloading a file, in background threads so that the UI thread remains free to respond
* to user inputs.</i>
* </ul>
*
* <li>CORBA - At the asynchronous layer one thread is associated with each socket that is connected
* to the client. Thread blocks waiting for CORBA requests from the client. On receiving request it
* is inserted in the queuing layer which is then picked up by synchronous layer which processes the
* request and sends response back to the client.</li>
* <li>Android AsyncTask framework - Framework provides a way to execute long running blocking
* calls, such as downloading a file, in background threads so that the UI thread remains free to
* respond to user inputs.</i>
* </ul>
*
* <p>
* <i>IMPLEMENTATION</i>
* <br/>
* The main method creates an asynchronous service which does not block the main thread while
* the task is being performed. The main thread continues its work which is similar to Async Method
* Invocation pattern. The difference between them is that there is a queuing layer between Asynchronous
* layer and synchronous layer, which allows for different communication patterns between both layers.
* Such as Priority Queue can be used as queuing layer to prioritize the way tasks are executed.
* Our implementation is just one simple way of implementing this pattern, there are many variants possible
* as described in its applications.
* <i>IMPLEMENTATION</i> <br/>
* The main method creates an asynchronous service which does not block the main thread while the
* task is being performed. The main thread continues its work which is similar to Async Method
* Invocation pattern. The difference between them is that there is a queuing layer between
* Asynchronous layer and synchronous layer, which allows for different communication patterns
* between both layers. Such as Priority Queue can be used as queuing layer to prioritize the way
* tasks are executed. Our implementation is just one simple way of implementing this pattern, there
* are many variants possible as described in its applications.
*
*/
public class App {
/**
* Program entry point
* @param args command line args
*/
public static void main(String[] args) {
AsynchronousService service = new AsynchronousService(new LinkedBlockingQueue<>());
/*
* A new task to calculate sum is received but as this is main thread, it should not block.
* So it passes it to the asynchronous task layer to compute and proceeds with handling other
* incoming requests. This is particularly useful when main thread is waiting on Socket to receive
* new incoming requests and does not wait for particular request to be completed before responding
* to new request.
*/
service.execute(new ArithmeticSumTask(1000));
/* New task received, lets pass that to async layer for computation. So both requests will be
* executed in parallel.
*/
service.execute(new ArithmeticSumTask(500));
service.execute(new ArithmeticSumTask(2000));
service.execute(new ArithmeticSumTask(1));
}
/**
*
* ArithmeticSumTask
*
*/
static class ArithmeticSumTask implements AsyncTask<Long> {
private long n;
/**
* Program entry point
*
* @param args command line args
*/
public static void main(String[] args) {
AsynchronousService service = new AsynchronousService(new LinkedBlockingQueue<>());
/*
* A new task to calculate sum is received but as this is main thread, it should not block. So
* it passes it to the asynchronous task layer to compute and proceeds with handling other
* incoming requests. This is particularly useful when main thread is waiting on Socket to
* receive new incoming requests and does not wait for particular request to be completed before
* responding to new request.
*/
service.execute(new ArithmeticSumTask(1000));
public ArithmeticSumTask(long n) {
this.n = n;
}
/*
* New task received, lets pass that to async layer for computation. So both requests will be
* executed in parallel.
*/
service.execute(new ArithmeticSumTask(500));
service.execute(new ArithmeticSumTask(2000));
service.execute(new ArithmeticSumTask(1));
}
/*
* This is the long running task that is performed in background. In our example
* the long running task is calculating arithmetic sum with artificial delay.
*/
@Override
public Long call() throws Exception {
return ap(n);
}
/**
*
* ArithmeticSumTask
*
*/
static class ArithmeticSumTask implements AsyncTask<Long> {
private long n;
/*
* This will be called in context of the main thread where some validations can be
* done regarding the inputs. Such as it must be greater than 0. It's a small
* computation which can be performed in main thread. If we did validated the input
* in background thread then we pay the cost of context switching
* which is much more than validating it in main thread.
*/
@Override
public void onPreCall() {
if (n < 0) {
throw new IllegalArgumentException("n is less than 0");
}
}
public ArithmeticSumTask(long n) {
this.n = n;
}
@Override
public void onPostCall(Long result) {
// Handle the result of computation
System.out.println(result);
}
/*
* This is the long running task that is performed in background. In our example the long
* running task is calculating arithmetic sum with artificial delay.
*/
@Override
public Long call() throws Exception {
return ap(n);
}
@Override
public void onError(Throwable throwable) {
throw new IllegalStateException("Should not occur");
}
}
private static long ap(long i) {
try {
Thread.sleep(i);
} catch (InterruptedException e) {
}
return (i) * (i + 1) / 2;
}
/*
* This will be called in context of the main thread where some validations can be done
* regarding the inputs. Such as it must be greater than 0. It's a small computation which can
* be performed in main thread. If we did validated the input in background thread then we pay
* the cost of context switching which is much more than validating it in main thread.
*/
@Override
public void onPreCall() {
if (n < 0) {
throw new IllegalArgumentException("n is less than 0");
}
}
@Override
public void onPostCall(Long result) {
// Handle the result of computation
System.out.println(result);
}
@Override
public void onError(Throwable throwable) {
throw new IllegalStateException("Should not occur");
}
}
private static long ap(long i) {
try {
Thread.sleep(i);
} catch (InterruptedException e) {
}
return (i) * (i + 1) / 2;
}
}

68
half-sync-half-async/src/main/java/com/iluwatar/halfsynchalfasync/AsyncTask.java
View File

@ -3,42 +3,42 @@ package com.iluwatar.halfsynchalfasync;
import java.util.concurrent.Callable;
/**
* Represents some computation that is performed asynchronously and its result.
* The computation is typically done is background threads and the result is posted
* back in form of callback. The callback does not implement {@code isComplete}, {@code cancel}
* as it is out of scope of this pattern.
* Represents some computation that is performed asynchronously and its result. The computation is
* typically done is background threads and the result is posted back in form of callback. The
* callback does not implement {@code isComplete}, {@code cancel} as it is out of scope of this
* pattern.
*
* @param <O> type of result
*/
public interface AsyncTask<O> extends Callable<O> {
/**
* Is called in context of caller thread before call to {@link #call()}. Large
* tasks should not be performed in this method as it will block the caller thread.
* Small tasks such as validations can be performed here so that the performance penalty
* of context switching is not incurred in case of invalid requests.
*/
void onPreCall();
/**
* A callback called after the result is successfully computed by {@link #call()}. In our
* implementation this method is called in context of background thread but in some variants,
* such as Android where only UI thread can change the state of UI widgets, this method is called
* in context of UI thread.
*/
void onPostCall(O result);
/**
* A callback called if computing the task resulted in some exception. This method
* is called when either of {@link #call()} or {@link #onPreCall()} throw any exception.
*
* @param throwable error cause
*/
void onError(Throwable throwable);
/**
* This is where the computation of task should reside. This method is called in context
* of background thread.
*/
@Override
O call() throws Exception;
/**
* Is called in context of caller thread before call to {@link #call()}. Large tasks should not be
* performed in this method as it will block the caller thread. Small tasks such as validations
* can be performed here so that the performance penalty of context switching is not incurred in
* case of invalid requests.
*/
void onPreCall();
/**
* A callback called after the result is successfully computed by {@link #call()}. In our
* implementation this method is called in context of background thread but in some variants, such
* as Android where only UI thread can change the state of UI widgets, this method is called in
* context of UI thread.
*/
void onPostCall(O result);
/**
* A callback called if computing the task resulted in some exception. This method is called when
* either of {@link #call()} or {@link #onPreCall()} throw any exception.
*
* @param throwable error cause
*/
void onError(Throwable throwable);
/**
* This is where the computation of task should reside. This method is called in context of
* background thread.
*/
@Override
O call() throws Exception;
}

116
half-sync-half-async/src/main/java/com/iluwatar/halfsynchalfasync/AsynchronousService.java
View File

@ -9,67 +9,67 @@ import java.util.concurrent.TimeUnit;
/**
* This is the asynchronous layer which does not block when a new request arrives. It just passes
* the request to the synchronous layer which consists of a queue i.e. a {@link BlockingQueue} and
* a pool of threads i.e. {@link ThreadPoolExecutor}. Out of this pool of worker threads one of the
* thread picks up the task and executes it synchronously in background and the result is posted back
* to the caller via callback.
* the request to the synchronous layer which consists of a queue i.e. a {@link BlockingQueue} and a
* pool of threads i.e. {@link ThreadPoolExecutor}. Out of this pool of worker threads one of the
* thread picks up the task and executes it synchronously in background and the result is posted
* back to the caller via callback.
*/
public class AsynchronousService {
/*
* This represents the queuing layer as well as synchronous layer of the pattern. The thread
* pool contains worker threads which execute the tasks in blocking/synchronous manner. Long
* running tasks should be performed in the background which does not affect the performance of
* main thread.
*/
private ExecutorService service;
/**
* Creates an asynchronous service using {@code workQueue} as communication channel between
* asynchronous layer and synchronous layer. Different types of queues such as Priority queue,
* can be used to control the pattern of communication between the layers.
*/
public AsynchronousService(BlockingQueue<Runnable> workQueue) {
service = new ThreadPoolExecutor(10, 10, 10, TimeUnit.SECONDS, workQueue);
}
/*
* This represents the queuing layer as well as synchronous layer of the pattern. The thread pool
* contains worker threads which execute the tasks in blocking/synchronous manner. Long running
* tasks should be performed in the background which does not affect the performance of main
* thread.
*/
private ExecutorService service;
/**
* A non-blocking method which performs the task provided in background and returns immediately.
* <p>
* On successful completion of task the result is posted back using callback method
* {@link AsyncTask#onPostCall(Object)}, if task execution is unable to complete normally
* due to some exception then the reason for error is posted back using callback method
* {@link AsyncTask#onError(Throwable)}.
* <p>
* NOTE: The results are posted back in the context of background thread in this implementation.
*/
public <T> void execute(final AsyncTask<T> task) {
try {
// some small tasks such as validation can be performed here.
task.onPreCall();
} catch (Exception e) {
task.onError(e);
}
/**
* Creates an asynchronous service using {@code workQueue} as communication channel between
* asynchronous layer and synchronous layer. Different types of queues such as Priority queue, can
* be used to control the pattern of communication between the layers.
*/
public AsynchronousService(BlockingQueue<Runnable> workQueue) {
service = new ThreadPoolExecutor(10, 10, 10, TimeUnit.SECONDS, workQueue);
}
service.submit(new FutureTask<T>(task) {
@Override
protected void done() {
super.done();
try {
/* called in context of background thread. There is other variant possible
* where result is posted back and sits in the queue of caller thread which
* then picks it up for processing. An example of such a system is Android OS,
* where the UI elements can only be updated using UI thread. So result must be
* posted back in UI thread.
*/
task.onPostCall(get());
} catch (InterruptedException e) {
// should not occur
} catch (ExecutionException e) {
task.onError(e.getCause());
}
}
});
}
/**
* A non-blocking method which performs the task provided in background and returns immediately.
* <p>
* On successful completion of task the result is posted back using callback method
* {@link AsyncTask#onPostCall(Object)}, if task execution is unable to complete normally due to
* some exception then the reason for error is posted back using callback method
* {@link AsyncTask#onError(Throwable)}.
* <p>
* NOTE: The results are posted back in the context of background thread in this implementation.
*/
public <T> void execute(final AsyncTask<T> task) {
try {
// some small tasks such as validation can be performed here.
task.onPreCall();
} catch (Exception e) {
task.onError(e);
}
service.submit(new FutureTask<T>(task) {
@Override
protected void done() {
super.done();
try {
/*
* called in context of background thread. There is other variant possible where result is
* posted back and sits in the queue of caller thread which then picks it up for
* processing. An example of such a system is Android OS, where the UI elements can only
* be updated using UI thread. So result must be posted back in UI thread.
*/
task.onPostCall(get());
} catch (InterruptedException e) {
// should not occur
} catch (ExecutionException e) {
task.onError(e.getCause());
}
}
});
}
}

8
half-sync-half-async/src/test/java/com/iluwatar/halfsynchalfasync/AppTest.java
View File

@ -11,8 +11,8 @@ import org.junit.Test;
*/
public class AppTest {
@Test
public void test() throws InterruptedException, ExecutionException {
App.main(null);
}
@Test
public void test() throws InterruptedException, ExecutionException {
App.main(null);
}
}

70
intercepting-filter/src/main/java/com/iluwatar/intercepting/filter/AbstractFilter.java
View File

@ -1,46 +1,44 @@
package com.iluwatar.intercepting.filter;
/**
* Base class for order processing filters.
* Handles chain management.
* Base class for order processing filters. Handles chain management.
*
*/
public abstract class AbstractFilter implements Filter {
private Filter next;
public AbstractFilter() {
}
private Filter next;
public AbstractFilter(Filter next) {
this.next = next;
}
@Override
public void setNext(Filter filter) {
this.next = filter;
}
@Override
public Filter getNext() {
return next;
}
public AbstractFilter() {}
@Override
public Filter getLast() {
Filter last = this;
while (last.getNext() != null) {
last = last.getNext();
}
return last;
}
@Override
public String execute(Order order) {
if (getNext() != null) {
return getNext().execute(order);
} else {
return "";
}
}
public AbstractFilter(Filter next) {
this.next = next;
}
@Override
public void setNext(Filter filter) {
this.next = filter;
}
@Override
public Filter getNext() {
return next;
}
@Override
public Filter getLast() {
Filter last = this;
while (last.getNext() != null) {
last = last.getNext();
}
return last;
}
@Override
public String execute(Order order) {
if (getNext() != null) {
return getNext().execute(order);
} else {
return "";
}
}
}

23
intercepting-filter/src/main/java/com/iluwatar/intercepting/filter/AddressFilter.java
View File

@ -1,19 +1,20 @@
package com.iluwatar.intercepting.filter;
/**
* Concrete implementation of filter
* This filter is responsible for checking/filtering the input in the address field.
* Concrete implementation of filter This filter is responsible for checking/filtering the input in
* the address field.
*
* @author joshzambales
*
*/
public class AddressFilter extends AbstractFilter {
@Override
public String execute(Order order) {
String result = super.execute(order);
if (order.getAddress() == null || order.getAddress().isEmpty()) {
return result + "Invalid address! ";
} else
return result;
}
@Override
public String execute(Order order) {
String result = super.execute(order);
if (order.getAddress() == null || order.getAddress().isEmpty()) {
return result + "Invalid address! ";
} else
return result;
}
}

70
intercepting-filter/src/main/java/com/iluwatar/intercepting/filter/App.java
View File

@ -2,50 +2,46 @@ package com.iluwatar.intercepting.filter;
/**
*
* When a request enters a Web application, it often must pass several entrance
* tests prior to the main processing stage. For example,
* - Has the client been authenticated?
* - Does the client have a valid session?
* - Is the client's IP address from a trusted network?
* - Does the request path violate any constraints?
* - What encoding does the client use to send the data?
* - Do we support the browser type of the client?
* Some of these checks are tests, resulting in a yes or no answer that determines
* whether processing will continue. Other checks manipulate the incoming data
* When a request enters a Web application, it often must pass several entrance tests prior to the
* main processing stage. For example, - Has the client been authenticated? - Does the client have a
* valid session? - Is the client's IP address from a trusted network? - Does the request path
* violate any constraints? - What encoding does the client use to send the data? - Do we support
* the browser type of the client? Some of these checks are tests, resulting in a yes or no answer
* that determines whether processing will continue. Other checks manipulate the incoming data
* stream into a form suitable for processing.
* <p>
* The classic solution consists of a series of conditional checks, with any failed
* check aborting the request. Nested if/else statements are a standard strategy,
* but this solution leads to code fragility and a copy-and-paste style of programming,
* because the flow of the filtering and the action of the filters is compiled into
* the application.
* The classic solution consists of a series of conditional checks, with any failed check aborting
* the request. Nested if/else statements are a standard strategy, but this solution leads to code
* fragility and a copy-and-paste style of programming, because the flow of the filtering and the
* action of the filters is compiled into the application.
* <p>
* The key to solving this problem in a flexible and unobtrusive manner is to have a
* simple mechanism for adding and removing processing components, in which each
* component completes a specific filtering action. This is the Intercepting Filter
* pattern in action.
* The key to solving this problem in a flexible and unobtrusive manner is to have a simple
* mechanism for adding and removing processing components, in which each component completes a
* specific filtering action. This is the Intercepting Filter pattern in action.
* <p>
* In this example we check whether the order request is valid through pre-processing
* done via {@link Filter}. Each field has its own corresponding {@link Filter}
* In this example we check whether the order request is valid through pre-processing done via
* {@link Filter}. Each field has its own corresponding {@link Filter}
* <p>
*
* @author joshzambales
*
*/
public class App{
/**
* Program entry point
* @param args command line args
*/
public static void main(String[] args) {
FilterManager filterManager = new FilterManager(new Target());
filterManager.addFilter(new NameFilter());
filterManager.addFilter(new ContactFilter());
filterManager.addFilter(new AddressFilter());
filterManager.addFilter(new DepositFilter());
filterManager.addFilter(new OrderFilter());
public class App {
Client client = new Client();
client.setFilterManager(filterManager);
}
/**
* Program entry point
*
* @param args command line args
*/
public static void main(String[] args) {
FilterManager filterManager = new FilterManager(new Target());
filterManager.addFilter(new NameFilter());
filterManager.addFilter(new ContactFilter());
filterManager.addFilter(new AddressFilter());
filterManager.addFilter(new DepositFilter());
filterManager.addFilter(new OrderFilter());
Client client = new Client();
client.setFilterManager(filterManager);
}
}

148
intercepting-filter/src/main/java/com/iluwatar/intercepting/filter/Client.java
View File

@ -15,93 +15,95 @@ import javax.swing.JTextField;
import javax.swing.SwingUtilities;
/**
* The Client class is responsible for handling the input and running them through filters inside the {@link FilterManager}.
* The Client class is responsible for handling the input and running them through filters inside
* the {@link FilterManager}.
*
* This is where {@link Filter}s come to play as the client pre-processes the request before being displayed in the {@link Target}.
* This is where {@link Filter}s come to play as the client pre-processes the request before being
* displayed in the {@link Target}.
*
* @author joshzambales
*
*/
public class Client extends JFrame {
private static final long serialVersionUID = 1L;
private static final long serialVersionUID = 1L;
private FilterManager filterManager;
private JLabel jl;
private JTextField[] jtFields;
private JTextArea[] jtAreas;
private JButton clearButton, processButton;
private FilterManager filterManager;
private JLabel jl;
private JTextField[] jtFields;
private JTextArea[] jtAreas;
private JButton clearButton, processButton;
public Client() {
super("Client System");
setDefaultCloseOperation(EXIT_ON_CLOSE);
setSize(300, 300);
jl = new JLabel("RUNNING...");
jtFields = new JTextField[3];
for (int i = 0; i < 3; i++) {
jtFields[i] = new JTextField();
}
jtAreas = new JTextArea[2];
for (int i = 0; i < 2; i++) {
jtAreas[i] = new JTextArea();
}
clearButton = new JButton("Clear");
processButton = new JButton("Process");
public Client() {
super("Client System");
setDefaultCloseOperation(EXIT_ON_CLOSE);
setSize(300, 300);
jl = new JLabel("RUNNING...");
jtFields = new JTextField[3];
for (int i = 0; i < 3; i++) {
jtFields[i] = new JTextField();
}
jtAreas = new JTextArea[2];
for (int i = 0; i < 2; i++) {
jtAreas[i] = new JTextArea();
}
clearButton = new JButton("Clear");
processButton = new JButton("Process");
setup();
}
setup();
}
private void setup() {
setLayout(new BorderLayout());
JPanel panel = new JPanel();
add(jl, BorderLayout.SOUTH);
add(panel, BorderLayout.CENTER);
panel.setLayout(new GridLayout(6, 2));
panel.add(new JLabel("Name"));
panel.add(jtFields[0]);
panel.add(new JLabel("Contact Number"));
panel.add(jtFields[1]);
panel.add(new JLabel("Address"));
panel.add(jtAreas[0]);
panel.add(new JLabel("Deposit Number"));
panel.add(jtFields[2]);
panel.add(new JLabel("Order"));
panel.add(jtAreas[1]);
panel.add(clearButton);
panel.add(processButton);
private void setup() {
setLayout(new BorderLayout());
JPanel panel = new JPanel();
add(jl, BorderLayout.SOUTH);
add(panel, BorderLayout.CENTER);
panel.setLayout(new GridLayout(6, 2));
panel.add(new JLabel("Name"));
panel.add(jtFields[0]);
panel.add(new JLabel("Contact Number"));
panel.add(jtFields[1]);
panel.add(new JLabel("Address"));
panel.add(jtAreas[0]);
panel.add(new JLabel("Deposit Number"));
panel.add(jtFields[2]);
panel.add(new JLabel("Order"));
panel.add(jtAreas[1]);
panel.add(clearButton);
panel.add(processButton);
clearButton.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
for (JTextArea i : jtAreas) {
i.setText("");
}
for (JTextField i : jtFields) {
i.setText("");
}
}
});
clearButton.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
for (JTextArea i : jtAreas) {
i.setText("");
}
for (JTextField i : jtFields) {
i.setText("");
}
}
});
processButton.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
Order order = new Order(jtFields[0].getText(), jtFields[1]
.getText(), jtAreas[0].getText(),
jtFields[2].getText(), jtAreas[1].getText());
jl.setText(sendRequest(order));
}
});
processButton.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
Order order =
new Order(jtFields[0].getText(), jtFields[1].getText(), jtAreas[0].getText(),
jtFields[2].getText(), jtAreas[1].getText());
jl.setText(sendRequest(order));
}
});
JRootPane rootPane = SwingUtilities.getRootPane(processButton);
rootPane.setDefaultButton(processButton);
setVisible(true);
}
JRootPane rootPane = SwingUtilities.getRootPane(processButton);
rootPane.setDefaultButton(processButton);
setVisible(true);
}
public void setFilterManager(FilterManager filterManager) {
this.filterManager = filterManager;
}
public void setFilterManager(FilterManager filterManager) {
this.filterManager = filterManager;
}
public String sendRequest(Order order) {
return filterManager.filterRequest(order);
}
public String sendRequest(Order order) {
return filterManager.filterRequest(order);
}
}

32
intercepting-filter/src/main/java/com/iluwatar/intercepting/filter/ContactFilter.java
View File

@ -1,24 +1,24 @@
package com.iluwatar.intercepting.filter;
/**
* Concrete implementation of filter
* This filter checks for the contact field in which it checks if the input consist of numbers
* and it also checks if the input follows the length constraint (11 digits)
* Concrete implementation of filter This filter checks for the contact field in which it checks if
* the input consist of numbers and it also checks if the input follows the length constraint (11
* digits)
*
* @author joshzambales
*
*/
public class ContactFilter extends AbstractFilter {
@Override
public String execute(Order order) {
String result = super.execute(order);
if (order.getContactNumber() == null
|| order.getContactNumber().isEmpty()
|| order.getContactNumber().matches(".*[^\\d]+.*")
|| order.getContactNumber().length() != 11) {
return result + "Invalid contact number! ";
} else {
return result;
}
}
@Override
public String execute(Order order) {
String result = super.execute(order);
if (order.getContactNumber() == null || order.getContactNumber().isEmpty()
|| order.getContactNumber().matches(".*[^\\d]+.*")
|| order.getContactNumber().length() != 11) {
return result + "Invalid contact number! ";
} else {
return result;
}
}
}

24
intercepting-filter/src/main/java/com/iluwatar/intercepting/filter/DepositFilter.java
View File

@ -1,20 +1,20 @@
package com.iluwatar.intercepting.filter;
/**
* Concrete implementation of filter
* This checks for the deposit code
* Concrete implementation of filter This checks for the deposit code
*
* @author joshzambales
*
*/
public class DepositFilter extends AbstractFilter {
@Override
public String execute(Order order) {
String result = super.execute(order);
if (order.getDepositNumber() == null || order.getDepositNumber().isEmpty()) {
return result + "Invalid deposit number! ";
} else {
return result;
}
}
@Override
public String execute(Order order) {
String result = super.execute(order);
if (order.getDepositNumber() == null || order.getDepositNumber().isEmpty()) {
return result + "Invalid deposit number! ";
} else {
return result;
}
}
}

59
intercepting-filter/src/main/java/com/iluwatar/intercepting/filter/Filter.java
View File

@ -1,37 +1,40 @@
package com.iluwatar.intercepting.filter;
/**
* Filters perform certain tasks prior or after execution of
* request by request handler. In this case, before the request is handled by
* the target, the request undergoes through each Filter
* Filters perform certain tasks prior or after execution of request by request handler. In this
* case, before the request is handled by the target, the request undergoes through each Filter
*
* @author joshzambales
*
*/
public interface Filter {
/**
* Execute order processing filter.
* @param order
* @return empty string on success, otherwise error message.
*/
String execute(Order order);
/**
* Set next filter in chain after this.
* @param filter
*/
void setNext(Filter filter);
/**
* Get next filter in chain after this.
* @return
*/
Filter getNext();
/**
* Get last filter in the chain.
* @return
*/
Filter getLast();
/**
* Execute order processing filter.
*
* @param order
* @return empty string on success, otherwise error message.
*/
String execute(Order order);
/**
* Set next filter in chain after this.
*
* @param filter
*/
void setNext(Filter filter);
/**
* Get next filter in chain after this.
*
* @return
*/
Filter getNext();
/**
* Get last filter in the chain.
*
* @return
*/
Filter getLast();
}

48
intercepting-filter/src/main/java/com/iluwatar/intercepting/filter/FilterChain.java
View File

@ -1,34 +1,34 @@
package com.iluwatar.intercepting.filter;
package com.iluwatar.intercepting.filter;
/**
* Filter Chain carries multiple filters and help to execute them in defined order on target.
*
* @author joshzambales
*/
public class FilterChain {
private Filter chain;
private final Target target;
public FilterChain(Target target) {
this.target = target;
}
private Filter chain;
public void addFilter(Filter filter) {
if (chain == null) {
chain = filter;
} else {
chain.getLast().setNext(filter);
}
}
private final Target target;
public String execute(Order order) {
if (chain != null) {
return chain.execute(order);
} else {
return "RUNNING...";
}
}
public FilterChain(Target target) {
this.target = target;
}
public void addFilter(Filter filter) {
if (chain == null) {
chain = filter;
} else {
chain.getLast().setNext(filter);
}
}
public String execute(Order order) {
if (chain != null) {
return chain.execute(order);
} else {
return "RUNNING...";
}
}
}

22
intercepting-filter/src/main/java/com/iluwatar/intercepting/filter/FilterManager.java
View File

@ -7,18 +7,18 @@ package com.iluwatar.intercepting.filter;
*
*/
public class FilterManager {
private FilterChain filterChain;
public FilterManager(Target target) {
filterChain = new FilterChain(target);
}
private FilterChain filterChain;
public void addFilter(Filter filter) {
filterChain.addFilter(filter);
}
public FilterManager(Target target) {
filterChain = new FilterChain(target);
}
public String filterRequest(Order order) {
return filterChain.execute(order);
}
public void addFilter(Filter filter) {
filterChain.addFilter(filter);
}
public String filterRequest(Order order) {
return filterChain.execute(order);
}
}

25
intercepting-filter/src/main/java/com/iluwatar/intercepting/filter/NameFilter.java
View File

@ -1,21 +1,22 @@
package com.iluwatar.intercepting.filter;
/**
* Concrete implementation of filter. This filter checks if the input in the Name
* field is valid. (alphanumeric)
* Concrete implementation of filter. This filter checks if the input in the Name field is valid.
* (alphanumeric)
*
* @author joshzambales
*
*/
public class NameFilter extends AbstractFilter {
@Override
public String execute(Order order) {
String result = super.execute(order);
if (order.getName() == null || order.getName().isEmpty() || order.getName().matches(".*[^\\w|\\s]+.*")) {
return result + "Invalid order! ";
} else {
return result;
}
}
@Override
public String execute(Order order) {
String result = super.execute(order);
if (order.getName() == null || order.getName().isEmpty()
|| order.getName().matches(".*[^\\w|\\s]+.*")) {
return result + "Invalid order! ";
} else {
return result;
}
}
}

91
intercepting-filter/src/main/java/com/iluwatar/intercepting/filter/Order.java
View File

@ -6,60 +6,59 @@ package com.iluwatar.intercepting.filter;
*/
public class Order {
private String name;
private String contactNumber;
private String address;
private String depositNumber;
private String order;
public Order() {
}
private String name;
private String contactNumber;
private String address;
private String depositNumber;
private String order;
public Order(String name, String contactNumber, String address, String depositNumber, String order) {
this.name = name;
this.contactNumber = contactNumber;
this.address = address;
this.depositNumber = depositNumber;
this.order = order;
}
public String getName() {
return name;
}
public Order() {}
public void setName(String name) {
this.name = name;
}
public Order(String name, String contactNumber, String address, String depositNumber, String order) {
this.name = name;
this.contactNumber = contactNumber;
this.address = address;
this.depositNumber = depositNumber;
this.order = order;
}
public String getContactNumber() {
return contactNumber;
}
public String getName() {
return name;
}
public void setContactNumber(String contactNumber) {
this.contactNumber = contactNumber;
}
public void setName(String name) {
this.name = name;
}
public String getAddress() {
return address;
}
public String getContactNumber() {
return contactNumber;
}
public void setAddress(String address) {
this.address = address;
}
public void setContactNumber(String contactNumber) {
this.contactNumber = contactNumber;
}
public String getDepositNumber() {
return depositNumber;
}
public String getAddress() {
return address;
}
public void setDepositNumber(String depositNumber) {
this.depositNumber = depositNumber;
}
public void setAddress(String address) {
this.address = address;
}
public String getOrder() {
return order;
}
public String getDepositNumber() {
return depositNumber;
}
public void setOrder(String order) {
this.order = order;
}
public void setDepositNumber(String depositNumber) {
this.depositNumber = depositNumber;
}
public String getOrder() {
return order;
}
public void setOrder(String order) {
this.order = order;
}
}

20
intercepting-filter/src/main/java/com/iluwatar/intercepting/filter/OrderFilter.java
View File

@ -7,14 +7,14 @@ package com.iluwatar.intercepting.filter;
*
*/
public class OrderFilter extends AbstractFilter {
@Override
public String execute(Order order) {
String result = super.execute(order);
if (order.getOrder() == null || order.getOrder().isEmpty()) {
return result + "Invalid order! ";
} else {
return result;
}
}
@Override
public String execute(Order order) {
String result = super.execute(order);
if (order.getOrder() == null || order.getOrder().isEmpty()) {
return result + "Invalid order! ";
} else {
return result;
}
}
}

92
intercepting-filter/src/main/java/com/iluwatar/intercepting/filter/Target.java
View File

@ -22,57 +22,57 @@ import javax.swing.table.DefaultTableModel;
*/
public class Target extends JFrame {
private static final long serialVersionUID = 1L;
private static final long serialVersionUID = 1L;
private JTable jt;
private JScrollPane jsp;
private DefaultTableModel dtm;
private JButton del;
private JTable jt;
private JScrollPane jsp;
private DefaultTableModel dtm;
private JButton del;
public Target() {
super("Order System");
setDefaultCloseOperation(EXIT_ON_CLOSE);
setSize(640, 480);
dtm = new DefaultTableModel(new Object[] { "Name", "Contact Number",
"Address", "Deposit Number", "Order" }, 0);
jt = new JTable(dtm);
del = new JButton("Delete");
setup();
}
public Target() {
super("Order System");
setDefaultCloseOperation(EXIT_ON_CLOSE);
setSize(640, 480);
dtm =
new DefaultTableModel(new Object[] {"Name", "Contact Number", "Address", "Deposit Number",
"Order"}, 0);
jt = new JTable(dtm);
del = new JButton("Delete");
setup();
}
private void setup() {
setLayout(new BorderLayout());
JPanel bot = new JPanel();
add(jt.getTableHeader(), BorderLayout.NORTH);
bot.setLayout(new BorderLayout());
bot.add(del, BorderLayout.EAST);
add(bot, BorderLayout.SOUTH);
jsp = new JScrollPane(jt);
jsp.setPreferredSize(new Dimension(500, 250));
add(jsp, BorderLayout.CENTER);
private void setup() {
setLayout(new BorderLayout());
JPanel bot = new JPanel();
add(jt.getTableHeader(), BorderLayout.NORTH);
bot.setLayout(new BorderLayout());
bot.add(del, BorderLayout.EAST);
add(bot, BorderLayout.SOUTH);
jsp = new JScrollPane(jt);
jsp.setPreferredSize(new Dimension(500, 250));
add(jsp, BorderLayout.CENTER);
del.addActionListener(new DListener());
del.addActionListener(new DListener());
JRootPane rootPane = SwingUtilities.getRootPane(del);
rootPane.setDefaultButton(del);
setVisible(true);
}
JRootPane rootPane = SwingUtilities.getRootPane(del);
rootPane.setDefaultButton(del);
setVisible(true);
}
public void execute(String[] request) {
dtm.addRow(new Object[] { request[0], request[1], request[2],
request[3], request[4] });
}
public void execute(String[] request) {
dtm.addRow(new Object[] {request[0], request[1], request[2], request[3], request[4]});
}
class DListener implements ActionListener {
@Override
public void actionPerformed(ActionEvent e) {
int temp = jt.getSelectedRow();
if (temp == -1)
return;
int temp2 = jt.getSelectedRowCount();
for (int i = 0; i < temp2; i++) {
dtm.removeRow(temp);
}
}
}
class DListener implements ActionListener {
@Override
public void actionPerformed(ActionEvent e) {
int temp = jt.getSelectedRow();
if (temp == -1)
return;
int temp2 = jt.getSelectedRowCount();
for (int i = 0; i < temp2; i++) {
dtm.removeRow(temp);
}
}
}
}

10
intercepting-filter/src/test/java/com/iluwatar/intercepting/filter/AppTest.java
View File

@ -11,9 +11,9 @@ import com.iluwatar.intercepting.filter.App;
*/
public class AppTest {
@Test
public void test() {
String[] args = {};
App.main(args);
}
@Test
public void test() {
String[] args = {};
App.main(args);
}
}

117
interpreter/src/main/java/com/iluwatar/interpreter/App.java
View File

@ -4,75 +4,66 @@ import java.util.Stack;
/**
*
* The Interpreter pattern is a design pattern that specifies how to evaluate sentences
* in a language. The basic idea is to have a class for each symbol (terminal or nonterminal)
* in a specialized computer language. The syntax tree of a sentence in the language is an
* instance of the composite pattern and is used to evaluate (interpret) the sentence for a
* client.
* The Interpreter pattern is a design pattern that specifies how to evaluate sentences in a
* language. The basic idea is to have a class for each symbol (terminal or nonterminal) in a
* specialized computer language. The syntax tree of a sentence in the language is an instance of
* the composite pattern and is used to evaluate (interpret) the sentence for a client.
* <p>
* In this example we use the Interpreter pattern to break sentences into expressions
* ({@link Expression}) that can be evaluated and as a whole form the result.
* In this example we use the Interpreter pattern to break sentences into expressions (
* {@link Expression}) that can be evaluated and as a whole form the result.
*
*/
public class App {
/**
*
* Program entry point.
* <p>
* Expressions can be evaluated using prefix, infix or postfix notations
* This sample uses postfix, where operator comes after the operands
*
* @param args command line args
*
*/
public static void main(String[] args) {
String tokenString = "4 3 2 - 1 + *";
Stack<Expression> stack = new Stack<>();
/**
*
* Program entry point.
* <p>
* Expressions can be evaluated using prefix, infix or postfix notations This sample uses postfix,
* where operator comes after the operands
*
* @param args command line args
*
*/
public static void main(String[] args) {
String tokenString = "4 3 2 - 1 + *";
Stack<Expression> stack = new Stack<>();
String[] tokenList = tokenString.split(" ");
for (String s : tokenList) {
if (isOperator(s)) {
Expression rightExpression = stack.pop();
Expression leftExpression = stack.pop();
System.out
.println(String.format(
"popped from stack left: %d right: %d",
leftExpression.interpret(),
rightExpression.interpret()));
Expression operator = getOperatorInstance(s, leftExpression,
rightExpression);
System.out.println(String.format("operator: %s", operator));
int result = operator.interpret();
NumberExpression resultExpression = new NumberExpression(result);
stack.push(resultExpression);
System.out.println(String.format("push result to stack: %d",
resultExpression.interpret()));
} else {
Expression i = new NumberExpression(s);
stack.push(i);
System.out.println(String.format("push to stack: %d",
i.interpret()));
}
}
System.out
.println(String.format("result: %d", stack.pop().interpret()));
}
String[] tokenList = tokenString.split(" ");
for (String s : tokenList) {
if (isOperator(s)) {
Expression rightExpression = stack.pop();
Expression leftExpression = stack.pop();
System.out.println(String.format("popped from stack left: %d right: %d",
leftExpression.interpret(), rightExpression.interpret()));
Expression operator = getOperatorInstance(s, leftExpression, rightExpression);
System.out.println(String.format("operator: %s", operator));
int result = operator.interpret();
NumberExpression resultExpression = new NumberExpression(result);
stack.push(resultExpression);
System.out.println(String.format("push result to stack: %d", resultExpression.interpret()));
} else {
Expression i = new NumberExpression(s);
stack.push(i);
System.out.println(String.format("push to stack: %d", i.interpret()));
}
}
System.out.println(String.format("result: %d", stack.pop().interpret()));
}
public static boolean isOperator(String s) {
return s.equals("+") || s.equals("-") || s.equals("*");
}
public static boolean isOperator(String s) {
return s.equals("+") || s.equals("-") || s.equals("*");
}
public static Expression getOperatorInstance(String s, Expression left,
Expression right) {
switch (s) {
case "+":
return new PlusExpression(left, right);
case "-":
return new MinusExpression(left, right);
case "*":
return new MultiplyExpression(left, right);
}
return null;
}
public static Expression getOperatorInstance(String s, Expression left, Expression right) {
switch (s) {
case "+":
return new PlusExpression(left, right);
case "-":
return new MinusExpression(left, right);
case "*":
return new MultiplyExpression(left, right);
}
return null;
}
}

6
interpreter/src/main/java/com/iluwatar/interpreter/Expression.java
View File

@ -7,8 +7,8 @@ package com.iluwatar.interpreter;
*/
public abstract class Expression {
public abstract int interpret();
public abstract int interpret();
@Override
public abstract String toString();
@Override
public abstract String toString();
}

28
interpreter/src/main/java/com/iluwatar/interpreter/MinusExpression.java
View File

@ -7,22 +7,22 @@ package com.iluwatar.interpreter;
*/
public class MinusExpression extends Expression {
private Expression leftExpression;
private Expression rightExpression;
private Expression leftExpression;
private Expression rightExpression;
public MinusExpression(Expression leftExpression, Expression rightExpression) {
this.leftExpression = leftExpression;
this.rightExpression = rightExpression;
}
public MinusExpression(Expression leftExpression, Expression rightExpression) {
this.leftExpression = leftExpression;
this.rightExpression = rightExpression;
}
@Override
public int interpret() {
return leftExpression.interpret() - rightExpression.interpret();
}
@Override
public int interpret() {
return leftExpression.interpret() - rightExpression.interpret();
}
@Override
public String toString() {
return "-";
}
@Override
public String toString() {
return "-";
}
}

29
interpreter/src/main/java/com/iluwatar/interpreter/MultiplyExpression.java
View File

@ -7,23 +7,22 @@ package com.iluwatar.interpreter;
*/
public class MultiplyExpression extends Expression {
private Expression leftExpression;
private Expression rightExpression;
private Expression leftExpression;
private Expression rightExpression;
public MultiplyExpression(Expression leftExpression,
Expression rightExpression) {
this.leftExpression = leftExpression;
this.rightExpression = rightExpression;
}
public MultiplyExpression(Expression leftExpression, Expression rightExpression) {
this.leftExpression = leftExpression;
this.rightExpression = rightExpression;
}
@Override
public int interpret() {
return leftExpression.interpret() * rightExpression.interpret();
}
@Override
public int interpret() {
return leftExpression.interpret() * rightExpression.interpret();
}
@Override
public String toString() {
return "*";
}
@Override
public String toString() {
return "*";
}
}

31
interpreter/src/main/java/com/iluwatar/interpreter/NumberExpression.java
View File

@ -7,24 +7,23 @@ package com.iluwatar.interpreter;
*/
public class NumberExpression extends Expression {
private int number;
private int number;
public NumberExpression(int number) {
this.number = number;
}
public NumberExpression(int number) {
this.number = number;
}
public NumberExpression(String s) {
this.number = Integer.parseInt(s);
}
public NumberExpression(String s) {
this.number = Integer.parseInt(s);
}
@Override
public int interpret() {
return number;
}
@Override
public String toString() {
return "number";
}
@Override
public int interpret() {
return number;
}
@Override
public String toString() {
return "number";
}
}

29
interpreter/src/main/java/com/iluwatar/interpreter/PlusExpression.java
View File

@ -7,22 +7,21 @@ package com.iluwatar.interpreter;
*/
public class PlusExpression extends Expression {
private Expression leftExpression;
private Expression rightExpression;
private Expression leftExpression;
private Expression rightExpression;
public PlusExpression(Expression leftExpression, Expression rightExpression) {
this.leftExpression = leftExpression;
this.rightExpression = rightExpression;
}
public PlusExpression(Expression leftExpression, Expression rightExpression) {
this.leftExpression = leftExpression;
this.rightExpression = rightExpression;
}
@Override
public int interpret() {
return leftExpression.interpret() + rightExpression.interpret();
}
@Override
public String toString() {
return "+";
}
@Override
public int interpret() {
return leftExpression.interpret() + rightExpression.interpret();
}
@Override
public String toString() {
return "+";
}
}

10
interpreter/src/test/java/com/iluwatar/interpreter/AppTest.java
View File

@ -11,9 +11,9 @@ import com.iluwatar.interpreter.App;
*/
public class AppTest {
@Test
public void test() {
String[] args = {};
App.main(args);
}
@Test
public void test() {
String[] args = {};
App.main(args);
}
}

64
iterator/src/main/java/com/iluwatar/iterator/App.java
View File

@ -2,48 +2,48 @@ package com.iluwatar.iterator;
/**
*
* The Iterator pattern is a design pattern in which an iterator is used to
* traverse a container and access the container's elements. The Iterator pattern
* decouples algorithms from containers.
* The Iterator pattern is a design pattern in which an iterator is used to traverse a container and
* access the container's elements. The Iterator pattern decouples algorithms from containers.
* <p>
* In this example the Iterator ({@link ItemIterator}) adds abstraction layer on
* top of a collection ({@link TreasureChest}). This way the collection can change
* its internal implementation without affecting its clients.
* In this example the Iterator ({@link ItemIterator}) adds abstraction layer on top of a collection
* ({@link TreasureChest}). This way the collection can change its internal implementation without
* affecting its clients.
*
*/
public class App {
/**
* Program entry point
* @param args command line args
*/
public static void main(String[] args) {
TreasureChest chest = new TreasureChest();
/**
* Program entry point
*
* @param args command line args
*/
public static void main(String[] args) {
TreasureChest chest = new TreasureChest();
ItemIterator ringIterator = chest.Iterator(ItemType.RING);
while (ringIterator.hasNext()) {
System.out.println(ringIterator.next());
}
ItemIterator ringIterator = chest.Iterator(ItemType.RING);
while (ringIterator.hasNext()) {
System.out.println(ringIterator.next());
}
System.out.println("----------");
System.out.println("----------");
ItemIterator potionIterator = chest.Iterator(ItemType.POTION);
while (potionIterator.hasNext()) {
System.out.println(potionIterator.next());
}
ItemIterator potionIterator = chest.Iterator(ItemType.POTION);
while (potionIterator.hasNext()) {
System.out.println(potionIterator.next());
}
System.out.println("----------");
System.out.println("----------");
ItemIterator weaponIterator = chest.Iterator(ItemType.WEAPON);
while (weaponIterator.hasNext()) {
System.out.println(weaponIterator.next());
}
ItemIterator weaponIterator = chest.Iterator(ItemType.WEAPON);
while (weaponIterator.hasNext()) {
System.out.println(weaponIterator.next());
}
System.out.println("----------");
System.out.println("----------");
ItemIterator it = chest.Iterator(ItemType.ANY);
while (it.hasNext()) {
System.out.println(it.next());
}
}
ItemIterator it = chest.Iterator(ItemType.ANY);
while (it.hasNext()) {
System.out.println(it.next());
}
}
}

32
iterator/src/main/java/com/iluwatar/iterator/Item.java
View File

@ -7,24 +7,24 @@ package com.iluwatar.iterator;
*/
public class Item {
private ItemType type;
private String name;
private ItemType type;
private String name;
public Item(ItemType type, String name) {
this.setType(type);
this.name = name;
}
public Item(ItemType type, String name) {
this.setType(type);
this.name = name;
}
@Override
public String toString() {
return name;
}
@Override
public String toString() {
return name;
}
public ItemType getType() {
return type;
}
public ItemType getType() {
return type;
}
public void setType(ItemType type) {
this.type = type;
}
public void setType(ItemType type) {
this.type = type;
}
}

4
iterator/src/main/java/com/iluwatar/iterator/ItemIterator.java
View File

@ -7,7 +7,7 @@ package com.iluwatar.iterator;
*/
public interface ItemIterator {
boolean hasNext();
boolean hasNext();
Item next();
Item next();
}

2
iterator/src/main/java/com/iluwatar/iterator/ItemType.java
View File

@ -7,6 +7,6 @@ package com.iluwatar.iterator;
*/
public enum ItemType {
ANY, WEAPON, RING, POTION
ANY, WEAPON, RING, POTION
}

44
iterator/src/main/java/com/iluwatar/iterator/TreasureChest.java
View File

@ -10,30 +10,30 @@ import java.util.List;
*/
public class TreasureChest {
private List<Item> items;
private List<Item> items;
public TreasureChest() {
items = new ArrayList<>();
items.add(new Item(ItemType.POTION, "Potion of courage"));
items.add(new Item(ItemType.RING, "Ring of shadows"));
items.add(new Item(ItemType.POTION, "Potion of wisdom"));
items.add(new Item(ItemType.POTION, "Potion of blood"));
items.add(new Item(ItemType.WEAPON, "Sword of silver +1"));
items.add(new Item(ItemType.POTION, "Potion of rust"));
items.add(new Item(ItemType.POTION, "Potion of healing"));
items.add(new Item(ItemType.RING, "Ring of armor"));
items.add(new Item(ItemType.WEAPON, "Steel halberd"));
items.add(new Item(ItemType.WEAPON, "Dagger of poison"));
}
public TreasureChest() {
items = new ArrayList<>();
items.add(new Item(ItemType.POTION, "Potion of courage"));
items.add(new Item(ItemType.RING, "Ring of shadows"));
items.add(new Item(ItemType.POTION, "Potion of wisdom"));
items.add(new Item(ItemType.POTION, "Potion of blood"));
items.add(new Item(ItemType.WEAPON, "Sword of silver +1"));
items.add(new Item(ItemType.POTION, "Potion of rust"));
items.add(new Item(ItemType.POTION, "Potion of healing"));
items.add(new Item(ItemType.RING, "Ring of armor"));
items.add(new Item(ItemType.WEAPON, "Steel halberd"));
items.add(new Item(ItemType.WEAPON, "Dagger of poison"));
}
ItemIterator Iterator(ItemType type) {
return new TreasureChestItemIterator(this, type);
}
ItemIterator Iterator(ItemType type) {
return new TreasureChestItemIterator(this, type);
}
public List<Item> getItems() {
ArrayList<Item> list = new ArrayList<>();
list.addAll(items);
return list;
}
public List<Item> getItems() {
ArrayList<Item> list = new ArrayList<>();
list.addAll(items);
return list;
}
}

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