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Merge pull request #281 from ankurkaushal/master

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Reformat according to google style guide
This commit is contained in:
Ilkka Seppälä 2015-11-02 21:39:17 +02:00
commit fe63c9cec4
438 changed files with 8257 additions and 8382 deletions
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138
abstract-factory/src/main/java/com/iluwatar/abstractfactory/App.java
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@ -3,80 +3,78 @@ package com.iluwatar.abstractfactory;
/** /**
* *
* The Abstract Factory pattern provides a way to encapsulate a group of individual * The Abstract Factory pattern provides a way to encapsulate a group of individual factories that
* factories that have a common theme without specifying their concrete classes. In * have a common theme without specifying their concrete classes. In normal usage, the client
* normal usage, the client software creates a concrete implementation of the abstract * software creates a concrete implementation of the abstract factory and then uses the generic
* factory and then uses the generic interface of the factory to create the concrete * interface of the factory to create the concrete objects that are part of the theme. The client
* objects that are part of the theme. The client does not know (or care) which * does not know (or care) which concrete objects it gets from each of these internal factories,
* concrete objects it gets from each of these internal factories, since it uses only * since it uses only the generic interfaces of their products. This pattern separates the details
* the generic interfaces of their products. This pattern separates the details of * of implementation of a set of objects from their general usage and relies on object composition,
* implementation of a set of objects from their general usage and relies on object * as object creation is implemented in methods exposed in the factory interface.
* composition, as object creation is implemented in methods exposed in the factory
* interface.
* <p> * <p>
* The essence of the Abstract Factory pattern is a factory interface * The essence of the Abstract Factory pattern is a factory interface ({@link KingdomFactory}) and
* ({@link KingdomFactory}) and its implementations ({@link ElfKingdomFactory}, * its implementations ({@link ElfKingdomFactory}, {@link OrcKingdomFactory}). The example uses both
* {@link OrcKingdomFactory}). The example uses both concrete implementations to * concrete implementations to create a king, a castle and an army.
* create a king, a castle and an army.
* *
*/ */
public class App { public class App {
private King king; private King king;
private Castle castle; private Castle castle;
private Army army; private Army army;
/** /**
* Creates kingdom * Creates kingdom
* @param factory *
*/ * @param factory
public void createKingdom(final KingdomFactory factory) { */
setKing(factory.createKing()); public void createKingdom(final KingdomFactory factory) {
setCastle(factory.createCastle()); setKing(factory.createKing());
setArmy(factory.createArmy()); setCastle(factory.createCastle());
} setArmy(factory.createArmy());
}
ElfKingdomFactory getElfKingdomFactory() {
return new ElfKingdomFactory(); ElfKingdomFactory getElfKingdomFactory() {
} return new ElfKingdomFactory();
}
OrcKingdomFactory getOrcKingdomFactory() {
return new OrcKingdomFactory(); OrcKingdomFactory getOrcKingdomFactory() {
} return new OrcKingdomFactory();
}
King getKing(final KingdomFactory factory) {
return factory.createKing(); King getKing(final KingdomFactory factory) {
} return factory.createKing();
}
Castle getCastle(final KingdomFactory factory) {
return factory.createCastle(); Castle getCastle(final KingdomFactory factory) {
} return factory.createCastle();
}
Army getArmy(final KingdomFactory factory) {
return factory.createArmy(); Army getArmy(final KingdomFactory factory) {
} return factory.createArmy();
}
public King getKing() {
return king; public King getKing() {
} return king;
}
private void setKing(final King king) {
this.king = king; private void setKing(final King king) {
} this.king = king;
}
public Castle getCastle() {
return castle; public Castle getCastle() {
} return castle;
}
private void setCastle(final Castle castle) {
this.castle = castle; private void setCastle(final Castle castle) {
} this.castle = castle;
}
public Army getArmy() {
return army; public Army getArmy() {
} return army;
}
private void setArmy(final Army army) {
this.army = army; private void setArmy(final Army army) {
} this.army = army;
}
} }

2
abstract-factory/src/main/java/com/iluwatar/abstractfactory/Army.java
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@ -7,5 +7,5 @@ package com.iluwatar.abstractfactory;
*/ */
public interface Army { public interface Army {
String getDescription(); String getDescription();
} }

2
abstract-factory/src/main/java/com/iluwatar/abstractfactory/Castle.java
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@ -7,5 +7,5 @@ package com.iluwatar.abstractfactory;
*/ */
public interface Castle { public interface Castle {
String getDescription(); String getDescription();
} }

10
abstract-factory/src/main/java/com/iluwatar/abstractfactory/ElfArmy.java
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@ -7,10 +7,10 @@ package com.iluwatar.abstractfactory;
*/ */
public class ElfArmy implements Army { public class ElfArmy implements Army {
static final String DESCRIPTION = "This is the Elven Army!"; static final String DESCRIPTION = "This is the Elven Army!";
@Override @Override
public String getDescription() { public String getDescription() {
return DESCRIPTION; return DESCRIPTION;
} }
} }

10
abstract-factory/src/main/java/com/iluwatar/abstractfactory/ElfCastle.java
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@ -7,10 +7,10 @@ package com.iluwatar.abstractfactory;
*/ */
public class ElfCastle implements Castle { public class ElfCastle implements Castle {
static final String DESCRIPTION = "This is the Elven castle!"; static final String DESCRIPTION = "This is the Elven castle!";
@Override @Override
public String getDescription() { public String getDescription() {
return DESCRIPTION; return DESCRIPTION;
} }
} }

12
abstract-factory/src/main/java/com/iluwatar/abstractfactory/ElfKing.java
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@ -7,10 +7,10 @@ package com.iluwatar.abstractfactory;
*/ */
public class ElfKing implements King { public class ElfKing implements King {
static final String DESCRIPTION = "This is the Elven king!"; static final String DESCRIPTION = "This is the Elven king!";
@Override @Override
public String getDescription() { public String getDescription() {
return DESCRIPTION; return DESCRIPTION;
} }
} }

18
abstract-factory/src/main/java/com/iluwatar/abstractfactory/ElfKingdomFactory.java
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@ -7,16 +7,16 @@ package com.iluwatar.abstractfactory;
*/ */
public class ElfKingdomFactory implements KingdomFactory { public class ElfKingdomFactory implements KingdomFactory {
public Castle createCastle() { public Castle createCastle() {
return new ElfCastle(); return new ElfCastle();
} }
public King createKing() { public King createKing() {
return new ElfKing(); return new ElfKing();
} }
public Army createArmy() { public Army createArmy() {
return new ElfArmy(); return new ElfArmy();
} }
} }

2
abstract-factory/src/main/java/com/iluwatar/abstractfactory/King.java
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@ -7,5 +7,5 @@ package com.iluwatar.abstractfactory;
*/ */
public interface King { public interface King {
String getDescription(); String getDescription();
} }

6
abstract-factory/src/main/java/com/iluwatar/abstractfactory/KingdomFactory.java
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@ -7,10 +7,10 @@ package com.iluwatar.abstractfactory;
*/ */
public interface KingdomFactory { public interface KingdomFactory {
Castle createCastle(); Castle createCastle();
King createKing(); King createKing();
Army createArmy(); Army createArmy();
} }

10
abstract-factory/src/main/java/com/iluwatar/abstractfactory/OrcArmy.java
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@ -7,10 +7,10 @@ package com.iluwatar.abstractfactory;
*/ */
public class OrcArmy implements Army { public class OrcArmy implements Army {
static final String DESCRIPTION = "This is the Orc Army!"; static final String DESCRIPTION = "This is the Orc Army!";
@Override @Override
public String getDescription() { public String getDescription() {
return DESCRIPTION; return DESCRIPTION;
} }
} }

10
abstract-factory/src/main/java/com/iluwatar/abstractfactory/OrcCastle.java
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@ -7,10 +7,10 @@ package com.iluwatar.abstractfactory;
*/ */
public class OrcCastle implements Castle { public class OrcCastle implements Castle {
static final String DESCRIPTION = "This is the Orc castle!"; static final String DESCRIPTION = "This is the Orc castle!";
@Override @Override
public String getDescription() { public String getDescription() {
return DESCRIPTION; return DESCRIPTION;
} }
} }

12
abstract-factory/src/main/java/com/iluwatar/abstractfactory/OrcKing.java
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@ -7,10 +7,10 @@ package com.iluwatar.abstractfactory;
*/ */
public class OrcKing implements King { public class OrcKing implements King {
static final String DESCRIPTION = "This is the Orc king!"; static final String DESCRIPTION = "This is the Orc king!";
@Override @Override
public String getDescription() { public String getDescription() {
return DESCRIPTION; return DESCRIPTION;
} }
} }

19
abstract-factory/src/main/java/com/iluwatar/abstractfactory/OrcKingdomFactory.java
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@ -7,16 +7,15 @@ package com.iluwatar.abstractfactory;
*/ */
public class OrcKingdomFactory implements KingdomFactory { public class OrcKingdomFactory implements KingdomFactory {
public Castle createCastle() { public Castle createCastle() {
return new OrcCastle(); return new OrcCastle();
} }
public King createKing() { public King createKing() {
return new OrcKing(); return new OrcKing();
} }
public Army createArmy() {
return new OrcArmy();
}
public Army createArmy() {
return new OrcArmy();
}
} }

135
abstract-factory/src/test/java/com/iluwatar/abstractfactory/AppTest.java
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@ -1,4 +1,5 @@
package com.iluwatar.abstractfactory; package com.iluwatar.abstractfactory;
import static org.junit.Assert.assertEquals; import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertTrue; import static org.junit.Assert.assertTrue;
@ -7,71 +8,71 @@ import org.junit.Test;
public class AppTest { public class AppTest {
private App app = new App(); private App app = new App();
private KingdomFactory elfFactory; private KingdomFactory elfFactory;
private KingdomFactory orcFactory; private KingdomFactory orcFactory;
@Before @Before
public void setUp() { public void setUp() {
elfFactory = app.getElfKingdomFactory(); elfFactory = app.getElfKingdomFactory();
orcFactory = app.getOrcKingdomFactory(); orcFactory = app.getOrcKingdomFactory();
} }
@Test @Test
public void king() { public void king() {
final King elfKing = app.getKing(elfFactory); final King elfKing = app.getKing(elfFactory);
assertTrue(elfKing instanceof ElfKing); assertTrue(elfKing instanceof ElfKing);
assertEquals(ElfKing.DESCRIPTION, elfKing.getDescription()); assertEquals(ElfKing.DESCRIPTION, elfKing.getDescription());
final King orcKing = app.getKing(orcFactory); final King orcKing = app.getKing(orcFactory);
assertTrue(orcKing instanceof OrcKing); assertTrue(orcKing instanceof OrcKing);
assertEquals(OrcKing.DESCRIPTION, orcKing.getDescription()); assertEquals(OrcKing.DESCRIPTION, orcKing.getDescription());
} }
@Test @Test
public void castle() { public void castle() {
final Castle elfCastle = app.getCastle(elfFactory); final Castle elfCastle = app.getCastle(elfFactory);
assertTrue(elfCastle instanceof ElfCastle); assertTrue(elfCastle instanceof ElfCastle);
assertEquals(ElfCastle.DESCRIPTION, elfCastle.getDescription()); assertEquals(ElfCastle.DESCRIPTION, elfCastle.getDescription());
final Castle orcCastle = app.getCastle(orcFactory); final Castle orcCastle = app.getCastle(orcFactory);
assertTrue(orcCastle instanceof OrcCastle); assertTrue(orcCastle instanceof OrcCastle);
assertEquals(OrcCastle.DESCRIPTION, orcCastle.getDescription()); assertEquals(OrcCastle.DESCRIPTION, orcCastle.getDescription());
} }
@Test @Test
public void army() { public void army() {
final Army elfArmy = app.getArmy(elfFactory); final Army elfArmy = app.getArmy(elfFactory);
assertTrue(elfArmy instanceof ElfArmy); assertTrue(elfArmy instanceof ElfArmy);
assertEquals(ElfArmy.DESCRIPTION, elfArmy.getDescription()); assertEquals(ElfArmy.DESCRIPTION, elfArmy.getDescription());
final Army orcArmy = app.getArmy(orcFactory); final Army orcArmy = app.getArmy(orcFactory);
assertTrue(orcArmy instanceof OrcArmy); assertTrue(orcArmy instanceof OrcArmy);
assertEquals(OrcArmy.DESCRIPTION, orcArmy.getDescription()); assertEquals(OrcArmy.DESCRIPTION, orcArmy.getDescription());
} }
@Test @Test
public void createElfKingdom() { public void createElfKingdom() {
app.createKingdom(elfFactory); app.createKingdom(elfFactory);
final King king = app.getKing(); final King king = app.getKing();
final Castle castle = app.getCastle(); final Castle castle = app.getCastle();
final Army army = app.getArmy(); final Army army = app.getArmy();
assertTrue(king instanceof ElfKing); assertTrue(king instanceof ElfKing);
assertEquals(ElfKing.DESCRIPTION, king.getDescription()); assertEquals(ElfKing.DESCRIPTION, king.getDescription());
assertTrue(castle instanceof ElfCastle); assertTrue(castle instanceof ElfCastle);
assertEquals(ElfCastle.DESCRIPTION, castle.getDescription()); assertEquals(ElfCastle.DESCRIPTION, castle.getDescription());
assertTrue(army instanceof ElfArmy); assertTrue(army instanceof ElfArmy);
assertEquals(ElfArmy.DESCRIPTION, army.getDescription()); assertEquals(ElfArmy.DESCRIPTION, army.getDescription());
} }
@Test @Test
public void createOrcKingdom() { public void createOrcKingdom() {
app.createKingdom(orcFactory); app.createKingdom(orcFactory);
final King king = app.getKing(); final King king = app.getKing();
final Castle castle = app.getCastle(); final Castle castle = app.getCastle();
final Army army = app.getArmy(); final Army army = app.getArmy();
assertTrue(king instanceof OrcKing); assertTrue(king instanceof OrcKing);
assertEquals(OrcKing.DESCRIPTION, king.getDescription()); assertEquals(OrcKing.DESCRIPTION, king.getDescription());
assertTrue(castle instanceof OrcCastle); assertTrue(castle instanceof OrcCastle);
assertEquals(OrcCastle.DESCRIPTION, castle.getDescription()); assertEquals(OrcCastle.DESCRIPTION, castle.getDescription());
assertTrue(army instanceof OrcArmy); assertTrue(army instanceof OrcArmy);
assertEquals(OrcArmy.DESCRIPTION, army.getDescription()); assertEquals(OrcArmy.DESCRIPTION, army.getDescription());
} }
} }

39
adapter/src/main/java/com/iluwatar/adapter/App.java
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@ -2,30 +2,29 @@ package com.iluwatar.adapter;
/** /**
* *
* An adapter helps two incompatible interfaces to work together. This is the real * An adapter helps two incompatible interfaces to work together. This is the real world definition
* world definition for an adapter. Interfaces may be incompatible but the inner * for an adapter. Interfaces may be incompatible but the inner functionality should suit the need.
* functionality should suit the need. The Adapter design pattern allows otherwise * The Adapter design pattern allows otherwise incompatible classes to work together by converting
* incompatible classes to work together by converting the interface of one class * the interface of one class into an interface expected by the clients.
* into an interface expected by the clients.
* <p> * <p>
* There are two variations of the Adapter pattern: The class adapter implements * There are two variations of the Adapter pattern: The class adapter implements the adaptee's
* the adaptee's interface whereas the object adapter uses composition to * interface whereas the object adapter uses composition to contain the adaptee in the adapter
* contain the adaptee in the adapter object. This example uses the object * object. This example uses the object adapter approach.
* adapter approach.
* <p> * <p>
* The Adapter ({@link GnomeEngineer}) converts the interface of the target class * The Adapter ({@link GnomeEngineer}) converts the interface of the target class (
* ({@link GoblinGlider}) into a suitable one expected by the client * {@link GoblinGlider}) into a suitable one expected by the client ({@link GnomeEngineeringManager}
* ({@link GnomeEngineeringManager}). * ).
* *
*/ */
public class App { public class App {
/** /**
* Program entry point * Program entry point
* @param args command line args *
*/ * @param args command line args
public static void main(String[] args) { */
Engineer manager = new GnomeEngineeringManager(); public static void main(String[] args) {
manager.operateDevice(); Engineer manager = new GnomeEngineeringManager();
} manager.operateDevice();
}
} }

3
adapter/src/main/java/com/iluwatar/adapter/Engineer.java
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@ -7,6 +7,5 @@ package com.iluwatar.adapter;
*/ */
public interface Engineer { public interface Engineer {
void operateDevice(); void operateDevice();
} }

25
adapter/src/main/java/com/iluwatar/adapter/GnomeEngineer.java
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@ -2,23 +2,22 @@ package com.iluwatar.adapter;
/** /**
* *
* Adapter class. Adapts the interface of the device ({@link GoblinGlider}) into * Adapter class. Adapts the interface of the device ({@link GoblinGlider}) into {@link Engineer}
* {@link Engineer} interface expected by the client ({@link GnomeEngineeringManager}). * interface expected by the client ({@link GnomeEngineeringManager}).
* *
*/ */
public class GnomeEngineer implements Engineer { public class GnomeEngineer implements Engineer {
private GoblinGlider glider; private GoblinGlider glider;
public GnomeEngineer() { public GnomeEngineer() {
glider = new GoblinGlider(); glider = new GoblinGlider();
} }
@Override
public void operateDevice() {
glider.attachGlider();
glider.gainSpeed();
glider.takeOff();
}
@Override
public void operateDevice() {
glider.attachGlider();
glider.gainSpeed();
glider.takeOff();
}
} }

16
adapter/src/main/java/com/iluwatar/adapter/GnomeEngineeringManager.java
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@ -7,14 +7,14 @@ package com.iluwatar.adapter;
*/ */
public class GnomeEngineeringManager implements Engineer { public class GnomeEngineeringManager implements Engineer {
private Engineer engineer; private Engineer engineer;
public GnomeEngineeringManager() { public GnomeEngineeringManager() {
engineer = new GnomeEngineer(); engineer = new GnomeEngineer();
} }
@Override @Override
public void operateDevice() { public void operateDevice() {
engineer.operateDevice(); engineer.operateDevice();
} }
} }

18
adapter/src/main/java/com/iluwatar/adapter/GoblinGlider.java
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@ -7,15 +7,15 @@ package com.iluwatar.adapter;
*/ */
public class GoblinGlider { public class GoblinGlider {
public void attachGlider() { public void attachGlider() {
System.out.println("Glider attached."); System.out.println("Glider attached.");
} }
public void gainSpeed() { public void gainSpeed() {
System.out.println("Gaining speed."); System.out.println("Gaining speed.");
} }
public void takeOff() { public void takeOff() {
System.out.println("Lift-off!"); System.out.println("Lift-off!");
} }
} }

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

139
async-method-invocation/src/main/java/com/iluwatar/async/method/invocation/App.java
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@ -4,23 +4,24 @@ import java.util.concurrent.Callable;
/** /**
* This application demonstrates the async method invocation pattern. Key parts of the pattern are * This application demonstrates the async method invocation pattern. Key parts of the pattern are
* <code>AsyncResult</code> which is an intermediate container for an asynchronously evaluated value, * <code>AsyncResult</code> which is an intermediate container for an asynchronously evaluated
* <code>AsyncCallback</code> which can be provided to be executed on task completion and * value, <code>AsyncCallback</code> which can be provided to be executed on task completion and
* <code>AsyncExecutor</code> that manages the execution of the async tasks. * <code>AsyncExecutor</code> that manages the execution of the async tasks.
* <p> * <p>
* The main method shows example flow of async invocations. The main thread starts multiple tasks with * The main method shows example flow of async invocations. The main thread starts multiple tasks
* variable durations and then continues its own work. When the main thread has done it's job it collects * with variable durations and then continues its own work. When the main thread has done it's job
* the results of the async tasks. Two of the tasks are handled with callbacks, meaning the callbacks are * it collects the results of the async tasks. Two of the tasks are handled with callbacks, meaning
* executed immediately when the tasks complete. * the callbacks are executed immediately when the tasks complete.
* <p> * <p>
* Noteworthy difference of thread usage between the async results and callbacks is that the async results * Noteworthy difference of thread usage between the async results and callbacks is that the async
* are collected in the main thread but the callbacks are executed within the worker threads. This should be * results are collected in the main thread but the callbacks are executed within the worker
* noted when working with thread pools. * threads. This should be noted when working with thread pools.
* <p> * <p>
* Java provides its own implementations of async method invocation pattern. FutureTask, CompletableFuture * Java provides its own implementations of async method invocation pattern. FutureTask,
* and ExecutorService are the real world implementations of this pattern. But due to the nature of parallel * CompletableFuture and ExecutorService are the real world implementations of this pattern. But due
* programming, the implementations are not trivial. This example does not take all possible scenarios into * to the nature of parallel programming, the implementations are not trivial. This example does not
* account but rather provides a simple version that helps to understand the pattern. * take all possible scenarios into account but rather provides a simple version that helps to
* understand the pattern.
* *
* @see AsyncResult * @see AsyncResult
* @see AsyncCallback * @see AsyncCallback
@ -32,66 +33,68 @@ import java.util.concurrent.Callable;
*/ */
public class App { public class App {
public static void main(String[] args) throws Exception { public static void main(String[] args) throws Exception {
// construct a new executor that will run async tasks // construct a new executor that will run async tasks
AsyncExecutor executor = new ThreadAsyncExecutor(); AsyncExecutor executor = new ThreadAsyncExecutor();
// start few async tasks with varying processing times, two last with callback handlers // start few async tasks with varying processing times, two last with callback handlers
AsyncResult<Integer> asyncResult1 = executor.startProcess(lazyval(10, 500)); AsyncResult<Integer> asyncResult1 = executor.startProcess(lazyval(10, 500));
AsyncResult<String> asyncResult2 = executor.startProcess(lazyval("test", 300)); AsyncResult<String> asyncResult2 = executor.startProcess(lazyval("test", 300));
AsyncResult<Long> asyncResult3 = executor.startProcess(lazyval(50L, 700)); AsyncResult<Long> asyncResult3 = executor.startProcess(lazyval(50L, 700));
AsyncResult<Integer> asyncResult4 = executor.startProcess(lazyval(20, 400), callback("Callback result 4")); AsyncResult<Integer> asyncResult4 =
AsyncResult<String> asyncResult5 = executor.startProcess(lazyval("callback", 600), callback("Callback result 5")); executor.startProcess(lazyval(20, 400), callback("Callback result 4"));
AsyncResult<String> asyncResult5 =
executor.startProcess(lazyval("callback", 600), callback("Callback result 5"));
// emulate processing in the current thread while async tasks are running in their own threads // emulate processing in the current thread while async tasks are running in their own threads
Thread.sleep(350); // Oh boy I'm working hard here Thread.sleep(350); // Oh boy I'm working hard here
log("Some hard work done"); log("Some hard work done");
// wait for completion of the tasks // wait for completion of the tasks
Integer result1 = executor.endProcess(asyncResult1); Integer result1 = executor.endProcess(asyncResult1);
String result2 = executor.endProcess(asyncResult2); String result2 = executor.endProcess(asyncResult2);
Long result3 = executor.endProcess(asyncResult3); Long result3 = executor.endProcess(asyncResult3);
asyncResult4.await(); asyncResult4.await();
asyncResult5.await(); asyncResult5.await();
// log the results of the tasks, callbacks log immediately when complete // log the results of the tasks, callbacks log immediately when complete
log("Result 1: " + result1); log("Result 1: " + result1);
log("Result 2: " + result2); log("Result 2: " + result2);
log("Result 3: " + result3); log("Result 3: " + result3);
} }
/** /**
* Creates a callable that lazily evaluates to given value with artificial delay. * Creates a callable that lazily evaluates to given value with artificial delay.
* *
* @param value value to evaluate * @param value value to evaluate
* @param delayMillis artificial delay in milliseconds * @param delayMillis artificial delay in milliseconds
* @return new callable for lazy evaluation * @return new callable for lazy evaluation
*/ */
private static <T> Callable<T> lazyval(T value, long delayMillis) { private static <T> Callable<T> lazyval(T value, long delayMillis) {
return () -> { return () -> {
Thread.sleep(delayMillis); Thread.sleep(delayMillis);
log("Task completed with: " + value); log("Task completed with: " + value);
return value; return value;
}; };
} }
/** /**
* Creates a simple callback that logs the complete status of the async result. * Creates a simple callback that logs the complete status of the async result.
* *
* @param name callback name * @param name callback name
* @return new async callback * @return new async callback
*/ */
private static <T> AsyncCallback<T> callback(String name) { private static <T> AsyncCallback<T> callback(String name) {
return (value, ex) -> { return (value, ex) -> {
if (ex.isPresent()) { if (ex.isPresent()) {
log(name + " failed: " + ex.map(Exception::getMessage).orElse("")); log(name + " failed: " + ex.map(Exception::getMessage).orElse(""));
} else { } else {
log(name + ": " + value); log(name + ": " + value);
} }
}; };
} }
private static void log(String msg) { private static void log(String msg) {
System.out.println(String.format("[%1$-10s] - %2$s", Thread.currentThread().getName(), msg)); System.out.println(String.format("[%1$-10s] - %2$s", Thread.currentThread().getName(), msg));
} }
} }

15
async-method-invocation/src/main/java/com/iluwatar/async/method/invocation/AsyncCallback.java
View File

@ -11,12 +11,11 @@ import java.util.Optional;
*/ */
public interface AsyncCallback<T> { public interface AsyncCallback<T> {
/** /**
* Complete handler which is executed when async task is completed or fails execution. * Complete handler which is executed when async task is completed or fails execution.
* *
* @param value the evaluated value from async task, undefined when execution fails * @param value the evaluated value from async task, undefined when execution fails
* @param ex empty value if execution succeeds, some exception if executions fails * @param ex empty value if execution succeeds, some exception if executions fails
*/ */
void onComplete(T value, Optional<Exception> ex); void onComplete(T value, Optional<Exception> ex);
} }

53
async-method-invocation/src/main/java/com/iluwatar/async/method/invocation/AsyncExecutor.java
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@ -10,33 +10,32 @@ import java.util.concurrent.ExecutionException;
*/ */
public interface AsyncExecutor { public interface AsyncExecutor {
/** /**
* Starts processing of an async task. Returns immediately with async result. * Starts processing of an async task. Returns immediately with async result.
* *
* @param task task to be executed asynchronously * @param task task to be executed asynchronously
* @return async result for the task * @return async result for the task
*/ */
<T> AsyncResult<T> startProcess(Callable<T> task); <T> AsyncResult<T> startProcess(Callable<T> task);
/** /**
* Starts processing of an async task. Returns immediately with async result. Executes callback * Starts processing of an async task. Returns immediately with async result. Executes callback
* when the task is completed. * when the task is completed.
* *
* @param task task to be executed asynchronously * @param task task to be executed asynchronously
* @param callback callback to be executed on task completion * @param callback callback to be executed on task completion
* @return async result for the task * @return async result for the task
*/ */
<T> AsyncResult<T> startProcess(Callable<T> task, AsyncCallback<T> callback); <T> AsyncResult<T> startProcess(Callable<T> task, AsyncCallback<T> callback);
/**
* Ends processing of an async task. Blocks the current thread if necessary and returns the
* evaluated value of the completed task.
*
* @param asyncResult async result of a task
* @return evaluated value of the completed task
* @throws ExecutionException if execution has failed, containing the root cause
* @throws InterruptedException if the execution is interrupted
*/
<T> T endProcess(AsyncResult<T> asyncResult) throws ExecutionException, InterruptedException;
/**
* Ends processing of an async task. Blocks the current thread if necessary and returns the
* evaluated value of the completed task.
*
* @param asyncResult async result of a task
* @return evaluated value of the completed task
* @throws ExecutionException if execution has failed, containing the root cause
* @throws InterruptedException if the execution is interrupted
*/
<T> T endProcess(AsyncResult<T> asyncResult) throws ExecutionException, InterruptedException;
} }

40
async-method-invocation/src/main/java/com/iluwatar/async/method/invocation/AsyncResult.java
View File

@ -10,26 +10,26 @@ import java.util.concurrent.ExecutionException;
*/ */
public interface AsyncResult<T> { public interface AsyncResult<T> {
/** /**
* Status of the async task execution. * Status of the async task execution.
* *
* @return <code>true</code> if execution is completed or failed * @return <code>true</code> if execution is completed or failed
*/ */
boolean isCompleted(); boolean isCompleted();
/** /**
* Gets the value of completed async task. * Gets the value of completed async task.
* *
* @return evaluated value or throws ExecutionException if execution has failed * @return evaluated value or throws ExecutionException if execution has failed
* @throws ExecutionException if execution has failed, containing the root cause * @throws ExecutionException if execution has failed, containing the root cause
* @throws IllegalStateException if execution is not completed * @throws IllegalStateException if execution is not completed
*/ */
T getValue() throws ExecutionException; T getValue() throws ExecutionException;
/** /**
* Blocks the current thread until the async task is completed. * Blocks the current thread until the async task is completed.
* *
* @throws InterruptedException if the execution is interrupted * @throws InterruptedException if the execution is interrupted
*/ */
void await() throws InterruptedException; void await() throws InterruptedException;
} }

199
async-method-invocation/src/main/java/com/iluwatar/async/method/invocation/ThreadAsyncExecutor.java
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@ -12,116 +12,117 @@ import java.util.concurrent.atomic.AtomicInteger;
*/ */
public class ThreadAsyncExecutor implements AsyncExecutor { public class ThreadAsyncExecutor implements AsyncExecutor {
/** Index for thread naming */ /** Index for thread naming */
private final AtomicInteger idx = new AtomicInteger(0); private final AtomicInteger idx = new AtomicInteger(0);
@Override @Override
public <T> AsyncResult<T> startProcess(Callable<T> task) { public <T> AsyncResult<T> startProcess(Callable<T> task) {
return startProcess(task, null); return startProcess(task, null);
} }
@Override @Override
public <T> AsyncResult<T> startProcess(Callable<T> task, AsyncCallback<T> callback) { public <T> AsyncResult<T> startProcess(Callable<T> task, AsyncCallback<T> callback) {
CompletableResult<T> result = new CompletableResult<>(callback); CompletableResult<T> result = new CompletableResult<>(callback);
new Thread(() -> { new Thread(() -> {
try { try {
result.setValue(task.call()); result.setValue(task.call());
} catch (Exception ex) { } catch (Exception ex) {
result.setException(ex); result.setException(ex);
} }
}, "executor-" + idx.incrementAndGet()).start(); }, "executor-" + idx.incrementAndGet()).start();
return result; return result;
} }
@Override @Override
public <T> T endProcess(AsyncResult<T> asyncResult) throws ExecutionException, InterruptedException { public <T> T endProcess(AsyncResult<T> asyncResult) throws ExecutionException,
if (asyncResult.isCompleted()) { InterruptedException {
return asyncResult.getValue(); if (asyncResult.isCompleted()) {
} else { return asyncResult.getValue();
asyncResult.await(); } else {
return asyncResult.getValue(); asyncResult.await();
} return asyncResult.getValue();
} }
}
/** /**
* Simple implementation of async result that allows completing it successfully with a value * Simple implementation of async result that allows completing it successfully with a value or
* or exceptionally with an exception. A really simplified version from its real life cousins * exceptionally with an exception. A really simplified version from its real life cousins
* FutureTask and CompletableFuture. * FutureTask and CompletableFuture.
* *
* @see java.util.concurrent.FutureTask * @see java.util.concurrent.FutureTask
* @see java.util.concurrent.CompletableFuture * @see java.util.concurrent.CompletableFuture
*/ */
private static class CompletableResult<T> implements AsyncResult<T> { private static class CompletableResult<T> implements AsyncResult<T> {
static final int RUNNING = 1; static final int RUNNING = 1;
static final int FAILED = 2; static final int FAILED = 2;
static final int COMPLETED = 3; static final int COMPLETED = 3;
final Object lock; final Object lock;
final Optional<AsyncCallback<T>> callback; final Optional<AsyncCallback<T>> callback;
volatile int state = RUNNING; volatile int state = RUNNING;
T value; T value;
Exception exception; Exception exception;
CompletableResult(AsyncCallback<T> callback) { CompletableResult(AsyncCallback<T> callback) {
this.lock = new Object(); this.lock = new Object();
this.callback = Optional.ofNullable(callback); this.callback = Optional.ofNullable(callback);
} }
/** /**
* Sets the value from successful execution and executes callback if available. Notifies * Sets the value from successful execution and executes callback if available. Notifies any
* any thread waiting for completion. * thread waiting for completion.
* *
* @param value value of the evaluated task * @param value value of the evaluated task
*/ */
void setValue(T value) { void setValue(T value) {
this.value = value; this.value = value;
this.state = COMPLETED; this.state = COMPLETED;
this.callback.ifPresent(ac -> ac.onComplete(value, Optional.<Exception>empty())); this.callback.ifPresent(ac -> ac.onComplete(value, Optional.<Exception>empty()));
synchronized (lock) { synchronized (lock) {
lock.notifyAll(); lock.notifyAll();
} }
} }
/** /**
* Sets the exception from failed execution and executes callback if available. Notifies * Sets the exception from failed execution and executes callback if available. Notifies any
* any thread waiting for completion. * thread waiting for completion.
* *
* @param exception exception of the failed task * @param exception exception of the failed task
*/ */
void setException(Exception exception) { void setException(Exception exception) {
this.exception = exception; this.exception = exception;
this.state = FAILED; this.state = FAILED;
this.callback.ifPresent(ac -> ac.onComplete(null, Optional.of(exception))); this.callback.ifPresent(ac -> ac.onComplete(null, Optional.of(exception)));
synchronized (lock) { synchronized (lock) {
lock.notifyAll(); lock.notifyAll();
} }
} }
@Override @Override
public boolean isCompleted() { public boolean isCompleted() {
return (state > RUNNING); return (state > RUNNING);
} }
@Override @Override
public T getValue() throws ExecutionException { public T getValue() throws ExecutionException {
if (state == COMPLETED) { if (state == COMPLETED) {
return value; return value;
} else if (state == FAILED) { } else if (state == FAILED) {
throw new ExecutionException(exception); throw new ExecutionException(exception);
} else { } else {
throw new IllegalStateException("Execution not completed yet"); throw new IllegalStateException("Execution not completed yet");
} }
} }
@Override @Override
public void await() throws InterruptedException { public void await() throws InterruptedException {
synchronized (lock) { synchronized (lock) {
if (!isCompleted()) { if (!isCompleted()) {
lock.wait(); lock.wait();
} }
} }
} }
} }
} }

11
async-method-invocation/src/test/java/com/iluwatar/async/method/invocation/AppTest.java
View File

@ -9,10 +9,9 @@ import org.junit.Test;
*/ */
public class AppTest { public class AppTest {
@Test @Test
public void test() throws Exception { public void test() throws Exception {
String[] args = {}; String[] args = {};
App.main(args); App.main(args);
} }
} }

57
bridge/src/main/java/com/iluwatar/bridge/App.java
View File

@ -2,41 +2,38 @@ package com.iluwatar.bridge;
/** /**
* *
* The Bridge pattern can also be thought of as two layers of abstraction. With Bridge, * The Bridge pattern can also be thought of as two layers of abstraction. With Bridge, you can
* you can decouple an abstraction from its implementation so that the two can vary independently. * decouple an abstraction from its implementation so that the two can vary independently.
* <p> * <p>
* In Bridge pattern both abstraction ({@link MagicWeapon}) and implementation * In Bridge pattern both abstraction ({@link MagicWeapon}) and implementation (
* ({@link MagicWeaponImpl}) have their own class hierarchies. The interface of the * {@link MagicWeaponImpl}) have their own class hierarchies. The interface of the implementations
* implementations can be changed without affecting the clients. * can be changed without affecting the clients.
* *
*/ */
public class App { public class App {
/** /**
* Program entry point * Program entry point
* @param args command line args *
*/ * @param args command line args
public static void main(String[] args) { */
BlindingMagicWeapon blindingMagicWeapon = new BlindingMagicWeapon( public static void main(String[] args) {
new Excalibur()); BlindingMagicWeapon blindingMagicWeapon = new BlindingMagicWeapon(new Excalibur());
blindingMagicWeapon.wield(); blindingMagicWeapon.wield();
blindingMagicWeapon.blind(); blindingMagicWeapon.blind();
blindingMagicWeapon.swing(); blindingMagicWeapon.swing();
blindingMagicWeapon.unwield(); blindingMagicWeapon.unwield();
FlyingMagicWeapon flyingMagicWeapon = new FlyingMagicWeapon( FlyingMagicWeapon flyingMagicWeapon = new FlyingMagicWeapon(new Mjollnir());
new Mjollnir()); flyingMagicWeapon.wield();
flyingMagicWeapon.wield(); flyingMagicWeapon.fly();
flyingMagicWeapon.fly(); flyingMagicWeapon.swing();
flyingMagicWeapon.swing(); flyingMagicWeapon.unwield();
flyingMagicWeapon.unwield();
SoulEatingMagicWeapon soulEatingMagicWeapon = new SoulEatingMagicWeapon( SoulEatingMagicWeapon soulEatingMagicWeapon = new SoulEatingMagicWeapon(new Stormbringer());
new Stormbringer()); soulEatingMagicWeapon.wield();
soulEatingMagicWeapon.wield(); soulEatingMagicWeapon.swing();
soulEatingMagicWeapon.swing(); soulEatingMagicWeapon.eatSoul();
soulEatingMagicWeapon.eatSoul(); soulEatingMagicWeapon.unwield();
soulEatingMagicWeapon.unwield(); }
}
} }

45
bridge/src/main/java/com/iluwatar/bridge/BlindingMagicWeapon.java
View File

@ -7,32 +7,31 @@ package com.iluwatar.bridge;
*/ */
public class BlindingMagicWeapon extends MagicWeapon { public class BlindingMagicWeapon extends MagicWeapon {
public BlindingMagicWeapon(BlindingMagicWeaponImpl imp) { public BlindingMagicWeapon(BlindingMagicWeaponImpl imp) {
super(imp); super(imp);
} }
@Override @Override
public BlindingMagicWeaponImpl getImp() { public BlindingMagicWeaponImpl getImp() {
return (BlindingMagicWeaponImpl) imp; return (BlindingMagicWeaponImpl) imp;
} }
@Override @Override
public void wield() { public void wield() {
getImp().wieldImp(); getImp().wieldImp();
} }
@Override @Override
public void swing() { public void swing() {
getImp().swingImp(); getImp().swingImp();
} }
@Override @Override
public void unwield() { public void unwield() {
getImp().unwieldImp(); getImp().unwieldImp();
} }
public void blind() {
getImp().blindImp();
}
public void blind() {
getImp().blindImp();
}
} }

2
bridge/src/main/java/com/iluwatar/bridge/BlindingMagicWeaponImpl.java
View File

@ -7,6 +7,6 @@ package com.iluwatar.bridge;
*/ */
public abstract class BlindingMagicWeaponImpl extends MagicWeaponImpl { public abstract class BlindingMagicWeaponImpl extends MagicWeaponImpl {
public abstract void blindImp(); public abstract void blindImp();
} }

34
bridge/src/main/java/com/iluwatar/bridge/Excalibur.java
View File

@ -7,25 +7,23 @@ package com.iluwatar.bridge;
*/ */
public class Excalibur extends BlindingMagicWeaponImpl { public class Excalibur extends BlindingMagicWeaponImpl {
@Override @Override
public void wieldImp() { public void wieldImp() {
System.out.println("wielding Excalibur"); System.out.println("wielding Excalibur");
} }
@Override @Override
public void swingImp() { public void swingImp() {
System.out.println("swinging Excalibur"); System.out.println("swinging Excalibur");
} }
@Override @Override
public void unwieldImp() { public void unwieldImp() {
System.out.println("unwielding Excalibur"); System.out.println("unwielding Excalibur");
} }
@Override
public void blindImp() {
System.out
.println("bright light streams from Excalibur blinding the enemy");
}
@Override
public void blindImp() {
System.out.println("bright light streams from Excalibur blinding the enemy");
}
} }

42
bridge/src/main/java/com/iluwatar/bridge/FlyingMagicWeapon.java
View File

@ -7,31 +7,31 @@ package com.iluwatar.bridge;
*/ */
public class FlyingMagicWeapon extends MagicWeapon { public class FlyingMagicWeapon extends MagicWeapon {
public FlyingMagicWeapon(FlyingMagicWeaponImpl imp) { public FlyingMagicWeapon(FlyingMagicWeaponImpl imp) {
super(imp); super(imp);
} }
public FlyingMagicWeaponImpl getImp() { public FlyingMagicWeaponImpl getImp() {
return (FlyingMagicWeaponImpl) imp; return (FlyingMagicWeaponImpl) imp;
} }
@Override @Override
public void wield() { public void wield() {
getImp().wieldImp(); getImp().wieldImp();
} }
@Override @Override
public void swing() { public void swing() {
getImp().swingImp(); getImp().swingImp();
} }
@Override @Override
public void unwield() { public void unwield() {
getImp().unwieldImp(); getImp().unwieldImp();
} }
public void fly() { public void fly() {
getImp().flyImp(); getImp().flyImp();
} }
} }

2
bridge/src/main/java/com/iluwatar/bridge/FlyingMagicWeaponImpl.java
View File

@ -7,6 +7,6 @@ package com.iluwatar.bridge;
*/ */
public abstract class FlyingMagicWeaponImpl extends MagicWeaponImpl { public abstract class FlyingMagicWeaponImpl extends MagicWeaponImpl {
public abstract void flyImp(); public abstract void flyImp();
} }

21
bridge/src/main/java/com/iluwatar/bridge/MagicWeapon.java
View File

@ -7,20 +7,19 @@ package com.iluwatar.bridge;
*/ */
public abstract class MagicWeapon { public abstract class MagicWeapon {
protected MagicWeaponImpl imp; protected MagicWeaponImpl imp;
public MagicWeapon(MagicWeaponImpl imp) { public MagicWeapon(MagicWeaponImpl imp) {
this.imp = imp; this.imp = imp;
} }
public abstract void wield(); public abstract void wield();
public abstract void swing(); public abstract void swing();
public abstract void unwield(); public abstract void unwield();
public MagicWeaponImpl getImp() {
return imp;
}
public MagicWeaponImpl getImp() {
return imp;
}
} }

6
bridge/src/main/java/com/iluwatar/bridge/MagicWeaponImpl.java
View File

@ -7,10 +7,10 @@ package com.iluwatar.bridge;
*/ */
public abstract class MagicWeaponImpl { public abstract class MagicWeaponImpl {
public abstract void wieldImp(); public abstract void wieldImp();
public abstract void swingImp(); public abstract void swingImp();
public abstract void unwieldImp(); public abstract void unwieldImp();
} }

34
bridge/src/main/java/com/iluwatar/bridge/Mjollnir.java
View File

@ -7,25 +7,23 @@ package com.iluwatar.bridge;
*/ */
public class Mjollnir extends FlyingMagicWeaponImpl { public class Mjollnir extends FlyingMagicWeaponImpl {
@Override @Override
public void wieldImp() { public void wieldImp() {
System.out.println("wielding Mjollnir"); System.out.println("wielding Mjollnir");
} }
@Override @Override
public void swingImp() { public void swingImp() {
System.out.println("swinging Mjollnir"); System.out.println("swinging Mjollnir");
} }
@Override @Override
public void unwieldImp() { public void unwieldImp() {
System.out.println("unwielding Mjollnir"); System.out.println("unwielding Mjollnir");
} }
@Override
public void flyImp() {
System.out
.println("Mjollnir hits the enemy in the air and returns back to the owner's hand");
}
@Override
public void flyImp() {
System.out.println("Mjollnir hits the enemy in the air and returns back to the owner's hand");
}
} }

44
bridge/src/main/java/com/iluwatar/bridge/SoulEatingMagicWeapon.java
View File

@ -7,32 +7,32 @@ package com.iluwatar.bridge;
*/ */
public class SoulEatingMagicWeapon extends MagicWeapon { public class SoulEatingMagicWeapon extends MagicWeapon {
public SoulEatingMagicWeapon(SoulEatingMagicWeaponImpl imp) { public SoulEatingMagicWeapon(SoulEatingMagicWeaponImpl imp) {
super(imp); super(imp);
} }
@Override @Override
public SoulEatingMagicWeaponImpl getImp() { public SoulEatingMagicWeaponImpl getImp() {
return (SoulEatingMagicWeaponImpl) imp; return (SoulEatingMagicWeaponImpl) imp;
} }
@Override @Override
public void wield() { public void wield() {
getImp().wieldImp(); getImp().wieldImp();
} }
@Override @Override
public void swing() { public void swing() {
getImp().swingImp(); getImp().swingImp();
} }
@Override @Override
public void unwield() { public void unwield() {
getImp().unwieldImp(); getImp().unwieldImp();
} }
public void eatSoul() { public void eatSoul() {
getImp().eatSoulImp(); getImp().eatSoulImp();
} }
} }

2
bridge/src/main/java/com/iluwatar/bridge/SoulEatingMagicWeaponImpl.java
View File

@ -7,6 +7,6 @@ package com.iluwatar.bridge;
*/ */
public abstract class SoulEatingMagicWeaponImpl extends MagicWeaponImpl { public abstract class SoulEatingMagicWeaponImpl extends MagicWeaponImpl {
public abstract void eatSoulImp(); public abstract void eatSoulImp();
} }

33
bridge/src/main/java/com/iluwatar/bridge/Stormbringer.java
View File

@ -7,24 +7,23 @@ package com.iluwatar.bridge;
*/ */
public class Stormbringer extends SoulEatingMagicWeaponImpl { public class Stormbringer extends SoulEatingMagicWeaponImpl {
@Override @Override
public void wieldImp() { public void wieldImp() {
System.out.println("wielding Stormbringer"); System.out.println("wielding Stormbringer");
} }
@Override @Override
public void swingImp() { public void swingImp() {
System.out.println("swinging Stormbringer"); System.out.println("swinging Stormbringer");
} }
@Override @Override
public void unwieldImp() { public void unwieldImp() {
System.out.println("unwielding Stormbringer"); System.out.println("unwielding Stormbringer");
} }
@Override
public void eatSoulImp() {
System.out.println("Stormbringer devours the enemy's soul");
}
@Override
public void eatSoulImp() {
System.out.println("Stormbringer devours the enemy's soul");
}
} }

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

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

76
builder/src/main/java/com/iluwatar/builder/App.java
View File

@ -1,55 +1,55 @@
package com.iluwatar.builder; package com.iluwatar.builder;
import com.iluwatar. builder.Hero.HeroBuilder; import com.iluwatar.builder.Hero.HeroBuilder;
/** /**
* *
* The intention of the Builder pattern is to find a solution to the telescoping * The intention of the Builder pattern is to find a solution to the telescoping constructor
* constructor anti-pattern. The telescoping constructor anti-pattern occurs when the * anti-pattern. The telescoping constructor anti-pattern occurs when the increase of object
* increase of object constructor parameter combination leads to an exponential list * constructor parameter combination leads to an exponential list of constructors. Instead of using
* of constructors. Instead of using numerous constructors, the builder pattern uses * numerous constructors, the builder pattern uses another object, a builder, that receives each
* another object, a builder, that receives each initialization parameter step by step * initialization parameter step by step and then returns the resulting constructed object at once.
* and then returns the resulting constructed object at once.
* <p> * <p>
* The Builder pattern has another benefit. It can be used for objects that contain * The Builder pattern has another benefit. It can be used for objects that contain flat data (html
* flat data (html code, SQL query, X.509 certificate...), that is to say, data that * code, SQL query, X.509 certificate...), that is to say, data that can't be easily edited. This
* can't be easily edited. This type of data cannot be edited step by step and must * type of data cannot be edited step by step and must be edited at once. The best way to construct
* be edited at once. The best way to construct such an object is to use a builder * such an object is to use a builder class.
* class.
* <p> * <p>
* In this example we have the Builder pattern variation as described by Joshua Bloch in * In this example we have the Builder pattern variation as described by Joshua Bloch in Effective
* Effective Java 2nd Edition. * Java 2nd Edition.
* <p> * <p>
* We want to build {@link Hero} objects, but its construction is complex because of the * We want to build {@link Hero} objects, but its construction is complex because of the many
* many parameters needed. To aid the user we introduce {@link HeroBuilder} class. * parameters needed. To aid the user we introduce {@link HeroBuilder} class. {@link HeroBuilder}
* {@link HeroBuilder} takes the minimum parameters to build {@link Hero} object in its * takes the minimum parameters to build {@link Hero} object in its constructor. After that
* constructor. After that additional configuration for the {@link Hero} object can be * additional configuration for the {@link Hero} object can be done using the fluent
* done using the fluent {@link HeroBuilder} interface. When configuration is ready the * {@link HeroBuilder} interface. When configuration is ready the build method is called to receive
* build method is called to receive the final {@link Hero} object. * the final {@link Hero} object.
* *
*/ */
public class App { public class App {
/** /**
* Program entry point * Program entry point
* @param args command line args *
*/ * @param args command line args
public static void main(String[] args) { */
public static void main(String[] args) {
Hero mage = new HeroBuilder(Profession.MAGE, "Riobard") Hero mage =
.withHairColor(HairColor.BLACK).withWeapon(Weapon.DAGGER) new HeroBuilder(Profession.MAGE, "Riobard").withHairColor(HairColor.BLACK)
.build(); .withWeapon(Weapon.DAGGER).build();
System.out.println(mage); System.out.println(mage);
Hero warrior = new HeroBuilder(Profession.WARRIOR, "Amberjill") Hero warrior =
.withHairColor(HairColor.BLOND) new HeroBuilder(Profession.WARRIOR, "Amberjill").withHairColor(HairColor.BLOND)
.withHairType(HairType.LONG_CURLY).withArmor(Armor.CHAIN_MAIL) .withHairType(HairType.LONG_CURLY).withArmor(Armor.CHAIN_MAIL).withWeapon(Weapon.SWORD)
.withWeapon(Weapon.SWORD).build(); .build();
System.out.println(warrior); System.out.println(warrior);
Hero thief = new HeroBuilder(Profession.THIEF, "Desmond") Hero thief =
.withHairType(HairType.BALD).withWeapon(Weapon.BOW).build(); new HeroBuilder(Profession.THIEF, "Desmond").withHairType(HairType.BALD)
System.out.println(thief); .withWeapon(Weapon.BOW).build();
System.out.println(thief);
} }
} }

18
builder/src/main/java/com/iluwatar/builder/Armor.java
View File

@ -7,16 +7,16 @@ package com.iluwatar.builder;
*/ */
public enum Armor { public enum Armor {
CLOTHES("clothes"), LEATHER("leather"), CHAIN_MAIL("chain mail"), PLATE_MAIL("plate mail"); CLOTHES("clothes"), LEATHER("leather"), CHAIN_MAIL("chain mail"), PLATE_MAIL("plate mail");
private String title; private String title;
Armor(String title) { Armor(String title) {
this.title = title; this.title = title;
} }
@Override @Override
public String toString() { public String toString() {
return title; return title;
} }
} }

10
builder/src/main/java/com/iluwatar/builder/HairColor.java
View File

@ -7,11 +7,11 @@ package com.iluwatar.builder;
*/ */
public enum HairColor { public enum HairColor {
WHITE, BLOND, RED, BROWN, BLACK; WHITE, BLOND, RED, BROWN, BLACK;
@Override @Override
public String toString() { public String toString() {
return name().toLowerCase(); return name().toLowerCase();
} }
} }

19
builder/src/main/java/com/iluwatar/builder/HairType.java
View File

@ -7,16 +7,17 @@ package com.iluwatar.builder;
*/ */
public enum HairType { public enum HairType {
BALD("bald"), SHORT("short"), CURLY("curly"), LONG_STRAIGHT("long straight"), LONG_CURLY("long curly"); BALD("bald"), SHORT("short"), CURLY("curly"), LONG_STRAIGHT("long straight"), LONG_CURLY(
"long curly");
private String title; private String title;
HairType(String title) { HairType(String title) {
this.title = title; this.title = title;
} }
@Override @Override
public String toString() { public String toString() {
return title; return title;
} }
} }

203
builder/src/main/java/com/iluwatar/builder/Hero.java
View File

@ -7,123 +7,122 @@ package com.iluwatar.builder;
*/ */
public class Hero { public class Hero {
private final Profession profession; private final Profession profession;
private final String name; private final String name;
private final HairType hairType; private final HairType hairType;
private final HairColor hairColor; private final HairColor hairColor;
private final Armor armor; private final Armor armor;
private final Weapon weapon; private final Weapon weapon;
public Profession getProfession() { public Profession getProfession() {
return profession; return profession;
} }
public String getName() { public String getName() {
return name; return name;
} }
public HairType getHairType() { public HairType getHairType() {
return hairType; return hairType;
} }
public HairColor getHairColor() { public HairColor getHairColor() {
return hairColor; return hairColor;
} }
public Armor getArmor() { public Armor getArmor() {
return armor; return armor;
} }
public Weapon getWeapon() { public Weapon getWeapon() {
return weapon; return weapon;
} }
@Override @Override
public String toString() { public String toString() {
StringBuilder sb = new StringBuilder(); StringBuilder sb = new StringBuilder();
sb.append("This is a "); sb.append("This is a ");
sb.append(profession); sb.append(profession);
sb.append(" named "); sb.append(" named ");
sb.append(name); sb.append(name);
if (hairColor != null || hairType != null) { if (hairColor != null || hairType != null) {
sb.append(" with "); sb.append(" with ");
if (hairColor != null) { if (hairColor != null) {
sb.append(hairColor); sb.append(hairColor);
sb.append(" "); sb.append(" ");
} }
if (hairType != null) { if (hairType != null) {
sb.append(hairType); sb.append(hairType);
sb.append(" "); sb.append(" ");
} }
sb.append(hairType != HairType.BALD ? "hair" : "head"); sb.append(hairType != HairType.BALD ? "hair" : "head");
} }
if (armor != null) { if (armor != null) {
sb.append(" wearing "); sb.append(" wearing ");
sb.append(armor); sb.append(armor);
} }
if (weapon != null) { if (weapon != null) {
sb.append(" and wielding a "); sb.append(" and wielding a ");
sb.append(weapon); sb.append(weapon);
} }
sb.append("."); sb.append(".");
return sb.toString(); return sb.toString();
} }
private Hero(HeroBuilder builder) { private Hero(HeroBuilder builder) {
this.profession = builder.profession; this.profession = builder.profession;
this.name = builder.name; this.name = builder.name;
this.hairColor = builder.hairColor; this.hairColor = builder.hairColor;
this.hairType = builder.hairType; this.hairType = builder.hairType;
this.weapon = builder.weapon; this.weapon = builder.weapon;
this.armor = builder.armor; this.armor = builder.armor;
} }
/** /**
* *
* The builder class. * The builder class.
* *
*/ */
public static class HeroBuilder { public static class HeroBuilder {
private final Profession profession; private final Profession profession;
private final String name; private final String name;
private HairType hairType; private HairType hairType;
private HairColor hairColor; private HairColor hairColor;
private Armor armor; private Armor armor;
private Weapon weapon; private Weapon weapon;
public HeroBuilder(Profession profession, String name) { public HeroBuilder(Profession profession, String name) {
if (profession == null || name == null) { if (profession == null || name == null) {
throw new IllegalArgumentException( throw new IllegalArgumentException("profession and name can not be null");
"profession and name can not be null"); }
} this.profession = profession;
this.profession = profession; this.name = name;
this.name = name; }
}
public HeroBuilder withHairType(HairType hairType) { public HeroBuilder withHairType(HairType hairType) {
this.hairType = hairType; this.hairType = hairType;
return this; return this;
} }
public HeroBuilder withHairColor(HairColor hairColor) { public HeroBuilder withHairColor(HairColor hairColor) {
this.hairColor = hairColor; this.hairColor = hairColor;
return this; return this;
} }
public HeroBuilder withArmor(Armor armor) { public HeroBuilder withArmor(Armor armor) {
this.armor = armor; this.armor = armor;
return this; return this;
} }
public HeroBuilder withWeapon(Weapon weapon) { public HeroBuilder withWeapon(Weapon weapon) {
this.weapon = weapon; this.weapon = weapon;
return this; return this;
} }
public Hero build() { public Hero build() {
return new Hero(this); return new Hero(this);
} }
} }
} }

11
builder/src/main/java/com/iluwatar/builder/Profession.java
View File

@ -7,11 +7,10 @@ package com.iluwatar.builder;
*/ */
public enum Profession { public enum Profession {
WARRIOR, THIEF, MAGE, PRIEST; WARRIOR, THIEF, MAGE, PRIEST;
@Override
public String toString() {
return name().toLowerCase();
}
@Override
public String toString() {
return name().toLowerCase();
}
} }

11
builder/src/main/java/com/iluwatar/builder/Weapon.java
View File

@ -7,11 +7,10 @@ package com.iluwatar.builder;
*/ */
public enum Weapon { public enum Weapon {
DAGGER, SWORD, AXE, WARHAMMER, BOW; DAGGER, SWORD, AXE, WARHAMMER, BOW;
@Override
public String toString() {
return name().toLowerCase();
}
@Override
public String toString() {
return name().toLowerCase();
}
} }

12
builder/src/test/java/com/iluwatar/builder/AppTest.java
View File

@ -2,7 +2,7 @@ package com.iluwatar.builder;
import org.junit.Test; import org.junit.Test;
import com.iluwatar. builder.App; import com.iluwatar.builder.App;
/** /**
* *
@ -11,9 +11,9 @@ import com.iluwatar. builder.App;
*/ */
public class AppTest { public class AppTest {
@Test @Test
public void test() { public void test() {
String[] args = {}; String[] args = {};
App.main(args); App.main(args);
} }
} }

48
business-delegate/src/main/java/com/iluwatar/business/delegate/App.java
View File

@ -2,34 +2,36 @@ package com.iluwatar.business.delegate;
/** /**
* *
* The Business Delegate pattern adds an abstraction layer between the presentation and business tiers. * The Business Delegate pattern adds an abstraction layer between the presentation and business
* By using the pattern we gain loose coupling between the tiers. The Business Delegate encapsulates * tiers. By using the pattern we gain loose coupling between the tiers. The Business Delegate
* knowledge about how to locate, connect to, and interact with the business objects that make up * encapsulates knowledge about how to locate, connect to, and interact with the business objects
* the application. * that make up the application.
* <p> * <p>
* Some of the services the Business Delegate uses are instantiated directly, and some can be retrieved * Some of the services the Business Delegate uses are instantiated directly, and some can be
* through service lookups. The Business Delegate itself may contain business logic too potentially tying * retrieved through service lookups. The Business Delegate itself may contain business logic too
* together multiple service calls, exception handling, retrying etc. * potentially tying together multiple service calls, exception handling, retrying etc.
* <p> * <p>
* In this example the client ({@link Client}) utilizes a business delegate ({@link BusinessDelegate}) to execute a task. * In this example the client ({@link Client}) utilizes a business delegate (
* The Business Delegate then selects the appropriate service and makes the service call. * {@link BusinessDelegate}) to execute a task. The Business Delegate then selects the appropriate
* service and makes the service call.
* *
*/ */
public class App { public class App {
/**
* Program entry point
* @param args command line args
*/
public static void main(String[] args) {
BusinessDelegate businessDelegate = new BusinessDelegate();
businessDelegate.setServiceType(ServiceType.EJB);
Client client = new Client(businessDelegate); /**
client.doTask(); * Program entry point
*
* @param args command line args
*/
public static void main(String[] args) {
businessDelegate.setServiceType(ServiceType.JMS); BusinessDelegate businessDelegate = new BusinessDelegate();
client.doTask(); businessDelegate.setServiceType(ServiceType.EJB);
}
Client client = new Client(businessDelegate);
client.doTask();
businessDelegate.setServiceType(ServiceType.JMS);
client.doTask();
}
} }

22
business-delegate/src/main/java/com/iluwatar/business/delegate/BusinessDelegate.java
View File

@ -6,17 +6,17 @@ package com.iluwatar.business.delegate;
* *
*/ */
public class BusinessDelegate { public class BusinessDelegate {
private BusinessLookup lookupService = new BusinessLookup();
private BusinessService businessService;
private ServiceType serviceType;
public void setServiceType(ServiceType serviceType) { private BusinessLookup lookupService = new BusinessLookup();
this.serviceType = serviceType; private BusinessService businessService;
} private ServiceType serviceType;
public void doTask() { public void setServiceType(ServiceType serviceType) {
businessService = lookupService.getBusinessService(serviceType); this.serviceType = serviceType;
businessService.doProcessing(); }
}
public void doTask() {
businessService = lookupService.getBusinessService(serviceType);
businessService.doProcessing();
}
} }

14
business-delegate/src/main/java/com/iluwatar/business/delegate/BusinessLookup.java
View File

@ -7,11 +7,11 @@ package com.iluwatar.business.delegate;
*/ */
public class BusinessLookup { public class BusinessLookup {
public BusinessService getBusinessService(ServiceType serviceType) { public BusinessService getBusinessService(ServiceType serviceType) {
if (serviceType.equals(ServiceType.EJB)) { if (serviceType.equals(ServiceType.EJB)) {
return new EjbService(); return new EjbService();
} else { } else {
return new JmsService(); return new JmsService();
} }
} }
} }

2
business-delegate/src/main/java/com/iluwatar/business/delegate/BusinessService.java
View File

@ -7,5 +7,5 @@ package com.iluwatar.business.delegate;
*/ */
public interface BusinessService { public interface BusinessService {
void doProcessing(); void doProcessing();
} }

14
business-delegate/src/main/java/com/iluwatar/business/delegate/Client.java
View File

@ -7,13 +7,13 @@ package com.iluwatar.business.delegate;
*/ */
public class Client { public class Client {
private BusinessDelegate businessDelegate; private BusinessDelegate businessDelegate;
public Client(BusinessDelegate businessDelegate) { public Client(BusinessDelegate businessDelegate) {
this.businessDelegate = businessDelegate; this.businessDelegate = businessDelegate;
} }
public void doTask() { public void doTask() {
businessDelegate.doTask(); businessDelegate.doTask();
} }
} }

8
business-delegate/src/main/java/com/iluwatar/business/delegate/EjbService.java
View File

@ -7,8 +7,8 @@ package com.iluwatar.business.delegate;
*/ */
public class EjbService implements BusinessService { public class EjbService implements BusinessService {
@Override @Override
public void doProcessing() { public void doProcessing() {
System.out.println("EjbService is now processing"); System.out.println("EjbService is now processing");
} }
} }

8
business-delegate/src/main/java/com/iluwatar/business/delegate/JmsService.java
View File

@ -7,8 +7,8 @@ package com.iluwatar.business.delegate;
*/ */
public class JmsService implements BusinessService { public class JmsService implements BusinessService {
@Override @Override
public void doProcessing() { public void doProcessing() {
System.out.println("JmsService is now processing"); System.out.println("JmsService is now processing");
} }
} }

4
business-delegate/src/main/java/com/iluwatar/business/delegate/ServiceType.java
View File

@ -6,6 +6,6 @@ package com.iluwatar.business.delegate;
* *
*/ */
public enum ServiceType { public enum ServiceType {
EJB, JMS; EJB, JMS;
} }

12
business-delegate/src/test/java/com/iluwatar/business/delegate/AppTest.java
View File

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

25
callback/src/main/java/com/iluwatar/callback/App.java
View File

@ -2,20 +2,21 @@ package com.iluwatar.callback;
/** /**
* *
* Callback pattern is more native for functional languages where functions are treated as first-class citizens. * Callback pattern is more native for functional languages where functions are treated as
* Prior to Java 8 callbacks can be simulated using simple (alike command) interfaces. * first-class citizens. Prior to Java 8 callbacks can be simulated using simple (alike command)
* interfaces.
* *
*/ */
public class App { public class App {
public static void main(String[] args) { public static void main(String[] args) {
Task task = new SimpleTask(); Task task = new SimpleTask();
Callback callback = new Callback() { Callback callback = new Callback() {
@Override @Override
public void call() { public void call() {
System.out.println("I'm done now."); System.out.println("I'm done now.");
} }
}; };
task.executeWith(callback); task.executeWith(callback);
} }
} }

2
callback/src/main/java/com/iluwatar/callback/Callback.java
View File

@ -7,5 +7,5 @@ package com.iluwatar.callback;
*/ */
public interface Callback { public interface Callback {
public void call(); public void call();
} }

9
callback/src/main/java/com/iluwatar/callback/SimpleTask.java
View File

@ -7,9 +7,8 @@ package com.iluwatar.callback;
*/ */
public class SimpleTask extends Task { public class SimpleTask extends Task {
@Override @Override
public void execute() { public void execute() {
System.out.println("Perform some important activity and after call the callback method."); System.out.println("Perform some important activity and after call the callback method.");
} }
} }

14
callback/src/main/java/com/iluwatar/callback/Task.java
View File

@ -7,12 +7,12 @@ package com.iluwatar.callback;
*/ */
public abstract class Task { public abstract class Task {
public final void executeWith(Callback callback) { public final void executeWith(Callback callback) {
execute(); execute();
if (callback != null) { if (callback != null) {
callback.call(); callback.call();
} }
} }
public abstract void execute(); public abstract void execute();
} }

36
callback/src/test/java/com/iluwatar/callback/AppTest.java
View File

@ -5,35 +5,35 @@ import org.junit.Test;
import static org.junit.Assert.assertEquals; import static org.junit.Assert.assertEquals;
/** /**
* Add a field as a counter. Every time the callback method is called increment this * Add a field as a counter. Every time the callback method is called increment this field. Unit
* field. Unit test checks that the field is being incremented. * test checks that the field is being incremented.
* *
* Could be done with mock objects as well where the call method call is verified. * Could be done with mock objects as well where the call method call is verified.
*/ */
public class AppTest { public class AppTest {
private Integer callingCount = 0; private Integer callingCount = 0;
@Test @Test
public void test() { public void test() {
Callback callback = new Callback() { Callback callback = new Callback() {
@Override @Override
public void call() { public void call() {
callingCount++; callingCount++;
} }
}; };
Task task = new SimpleTask(); Task task = new SimpleTask();
assertEquals("Initial calling count of 0", new Integer(0), callingCount); assertEquals("Initial calling count of 0", new Integer(0), callingCount);
task.executeWith(callback); task.executeWith(callback);
assertEquals("Callback called once", new Integer(1), callingCount); assertEquals("Callback called once", new Integer(1), callingCount);
task.executeWith(callback); task.executeWith(callback);
assertEquals("Callback called twice", new Integer(2), callingCount); assertEquals("Callback called twice", new Integer(2), callingCount);
} }
} }

39
chain/src/main/java/com/iluwatar/chain/App.java
View File

@ -2,31 +2,30 @@ package com.iluwatar.chain;
/** /**
* *
* The Chain of Responsibility pattern is a design pattern consisting of command * The Chain of Responsibility pattern is a design pattern consisting of command objects and a
* objects and a series of processing objects. Each processing object contains * series of processing objects. Each processing object contains logic that defines the types of
* logic that defines the types of command objects that it can handle; the rest are * command objects that it can handle; the rest are passed to the next processing object in the
* passed to the next processing object in the chain. A mechanism also exists for * chain. A mechanism also exists for adding new processing objects to the end of this chain.
* adding new processing objects to the end of this chain.
* <p> * <p>
* In this example we organize the request handlers ({@link RequestHandler}) into a * In this example we organize the request handlers ({@link RequestHandler}) into a chain where each
* chain where each handler has a chance to act on the request on its turn. Here * handler has a chance to act on the request on its turn. Here the king ({@link OrcKing}) makes
* the king ({@link OrcKing}) makes requests and the military orcs ({@link OrcCommander}, * requests and the military orcs ({@link OrcCommander}, {@link OrcOfficer}, {@link OrcSoldier})
* {@link OrcOfficer}, {@link OrcSoldier}) form the handler chain. * form the handler chain.
* *
*/ */
public class App { public class App {
/** /**
* Program entry point * Program entry point
* @param args command line args *
*/ * @param args command line args
public static void main(String[] args) { */
public static void main(String[] args) {
OrcKing king = new OrcKing(); OrcKing king = new OrcKing();
king.makeRequest(new Request(RequestType.DEFEND_CASTLE, "defend castle")); king.makeRequest(new Request(RequestType.DEFEND_CASTLE, "defend castle"));
king.makeRequest(new Request(RequestType.TORTURE_PRISONER, king.makeRequest(new Request(RequestType.TORTURE_PRISONER, "torture prisoner"));
"torture prisoner")); king.makeRequest(new Request(RequestType.COLLECT_TAX, "collect tax"));
king.makeRequest(new Request(RequestType.COLLECT_TAX, "collect tax"));
} }
} }

30
chain/src/main/java/com/iluwatar/chain/OrcCommander.java
View File

@ -7,21 +7,21 @@ package com.iluwatar.chain;
*/ */
public class OrcCommander extends RequestHandler { public class OrcCommander extends RequestHandler {
public OrcCommander(RequestHandler handler) { public OrcCommander(RequestHandler handler) {
super(handler); super(handler);
} }
@Override @Override
public void handleRequest(Request req) { public void handleRequest(Request req) {
if (req.getRequestType().equals(RequestType.DEFEND_CASTLE)) { if (req.getRequestType().equals(RequestType.DEFEND_CASTLE)) {
printHandling(req); printHandling(req);
} else { } else {
super.handleRequest(req); super.handleRequest(req);
} }
} }
@Override @Override
public String toString() { public String toString() {
return "Orc commander"; return "Orc commander";
} }
} }

20
chain/src/main/java/com/iluwatar/chain/OrcKing.java
View File

@ -7,18 +7,18 @@ package com.iluwatar.chain;
*/ */
public class OrcKing { public class OrcKing {
RequestHandler chain; RequestHandler chain;
public OrcKing() { public OrcKing() {
buildChain(); buildChain();
} }
private void buildChain() { private void buildChain() {
chain = new OrcCommander(new OrcOfficer(new OrcSoldier(null))); chain = new OrcCommander(new OrcOfficer(new OrcSoldier(null)));
} }
public void makeRequest(Request req) { public void makeRequest(Request req) {
chain.handleRequest(req); chain.handleRequest(req);
} }
} }

30
chain/src/main/java/com/iluwatar/chain/OrcOfficer.java
View File

@ -7,22 +7,22 @@ package com.iluwatar.chain;
*/ */
public class OrcOfficer extends RequestHandler { public class OrcOfficer extends RequestHandler {
public OrcOfficer(RequestHandler handler) { public OrcOfficer(RequestHandler handler) {
super(handler); super(handler);
} }
@Override @Override
public void handleRequest(Request req) { public void handleRequest(Request req) {
if (req.getRequestType().equals(RequestType.TORTURE_PRISONER)) { if (req.getRequestType().equals(RequestType.TORTURE_PRISONER)) {
printHandling(req); printHandling(req);
} else { } else {
super.handleRequest(req); super.handleRequest(req);
} }
} }
@Override @Override
public String toString() { public String toString() {
return "Orc officer"; return "Orc officer";
} }
} }

30
chain/src/main/java/com/iluwatar/chain/OrcSoldier.java
View File

@ -7,21 +7,21 @@ package com.iluwatar.chain;
*/ */
public class OrcSoldier extends RequestHandler { public class OrcSoldier extends RequestHandler {
public OrcSoldier(RequestHandler handler) { public OrcSoldier(RequestHandler handler) {
super(handler); super(handler);
} }
@Override @Override
public void handleRequest(Request req) { public void handleRequest(Request req) {
if (req.getRequestType().equals(RequestType.COLLECT_TAX)) { if (req.getRequestType().equals(RequestType.COLLECT_TAX)) {
printHandling(req); printHandling(req);
} else { } else {
super.handleRequest(req); super.handleRequest(req);
} }
} }
@Override @Override
public String toString() { public String toString() {
return "Orc soldier"; return "Orc soldier";
} }
} }

44
chain/src/main/java/com/iluwatar/chain/Request.java
View File

@ -7,32 +7,32 @@ package com.iluwatar.chain;
*/ */
public class Request { public class Request {
private String requestDescription; private String requestDescription;
private RequestType requestType; private RequestType requestType;
public Request(RequestType requestType, String requestDescription) { public Request(RequestType requestType, String requestDescription) {
this.setRequestType(requestType); this.setRequestType(requestType);
this.setRequestDescription(requestDescription); this.setRequestDescription(requestDescription);
} }
public String getRequestDescription() { public String getRequestDescription() {
return requestDescription; return requestDescription;
} }
public void setRequestDescription(String requestDescription) { public void setRequestDescription(String requestDescription) {
this.requestDescription = requestDescription; this.requestDescription = requestDescription;
} }
public RequestType getRequestType() { public RequestType getRequestType() {
return requestType; return requestType;
} }
public void setRequestType(RequestType requestType) { public void setRequestType(RequestType requestType) {
this.requestType = requestType; this.requestType = requestType;
} }
@Override @Override
public String toString() { public String toString() {
return getRequestDescription(); return getRequestDescription();
} }
} }

28
chain/src/main/java/com/iluwatar/chain/RequestHandler.java
View File

@ -7,22 +7,22 @@ package com.iluwatar.chain;
*/ */
public abstract class RequestHandler { public abstract class RequestHandler {
private RequestHandler next; private RequestHandler next;
public RequestHandler(RequestHandler next) { public RequestHandler(RequestHandler next) {
this.next = next; this.next = next;
} }
public void handleRequest(Request req) { public void handleRequest(Request req) {
if (next != null) { if (next != null) {
next.handleRequest(req); next.handleRequest(req);
} }
} }
protected void printHandling(Request req) { protected void printHandling(Request req) {
System.out.println(this + " handling request \"" + req + "\""); System.out.println(this + " handling request \"" + req + "\"");
} }
@Override @Override
public abstract String toString(); public abstract String toString();
} }

2
chain/src/main/java/com/iluwatar/chain/RequestType.java
View File

@ -7,6 +7,6 @@ package com.iluwatar.chain;
*/ */
public enum RequestType { public enum RequestType {
DEFEND_CASTLE, TORTURE_PRISONER, COLLECT_TAX DEFEND_CASTLE, TORTURE_PRISONER, COLLECT_TAX
} }

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

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

70
command/src/main/java/com/iluwatar/command/App.java
View File

@ -2,52 +2,54 @@ package com.iluwatar.command;
/** /**
* *
* The Command pattern is a behavioral design pattern in which an object is used to encapsulate all information * The Command pattern is a behavioral design pattern in which an object is used to encapsulate all
* needed to perform an action or trigger an event at a later time. This information includes the method name, * information needed to perform an action or trigger an event at a later time. This information
* the object that owns the method and values for the method parameters. * includes the method name, the object that owns the method and values for the method parameters.
* <p> * <p>
* Four terms always associated with the command pattern are command, receiver, invoker and client. A command * Four terms always associated with the command pattern are command, receiver, invoker and client.
* object (spell) knows about the receiver (target) and invokes a method of the receiver. Values for parameters of * A command object (spell) knows about the receiver (target) and invokes a method of the receiver.
* the receiver method are stored in the command. The receiver then does the work. An invoker object (wizard) * Values for parameters of the receiver method are stored in the command. The receiver then does
* knows how to execute a command, and optionally does bookkeeping about the command execution. The invoker * the work. An invoker object (wizard) knows how to execute a command, and optionally does
* does not know anything about a concrete command, it knows only about command interface. Both an invoker object * bookkeeping about the command execution. The invoker does not know anything about a concrete
* and several command objects are held by a client object (app). The client decides which commands to execute at * command, it knows only about command interface. Both an invoker object and several command
* which points. To execute a command, it passes the command object to the invoker object. * objects are held by a client object (app). The client decides which commands to execute at which
* points. To execute a command, it passes the command object to the invoker object.
* <p> * <p>
* In other words, in this example the wizard casts spells on the goblin. The wizard keeps track of the previous * In other words, in this example the wizard casts spells on the goblin. The wizard keeps track of
* spells cast, so it is easy to undo them. In addition, the wizard keeps track of the spells undone, so they * the previous spells cast, so it is easy to undo them. In addition, the wizard keeps track of the
* can be redone. * spells undone, so they can be redone.
* *
* *
*/ */
public class App { public class App {
/** /**
* Program entry point * Program entry point
* @param args command line args *
*/ * @param args command line args
public static void main(String[] args) { */
Wizard wizard = new Wizard(); public static void main(String[] args) {
Goblin goblin = new Goblin(); Wizard wizard = new Wizard();
Goblin goblin = new Goblin();
goblin.printStatus(); goblin.printStatus();
wizard.castSpell(new ShrinkSpell(), goblin); wizard.castSpell(new ShrinkSpell(), goblin);
goblin.printStatus(); goblin.printStatus();
wizard.castSpell(new InvisibilitySpell(), goblin); wizard.castSpell(new InvisibilitySpell(), goblin);
goblin.printStatus(); goblin.printStatus();
wizard.undoLastSpell(); wizard.undoLastSpell();
goblin.printStatus(); goblin.printStatus();
wizard.undoLastSpell(); wizard.undoLastSpell();
goblin.printStatus(); goblin.printStatus();
wizard.redoLastSpell(); wizard.redoLastSpell();
goblin.printStatus(); goblin.printStatus();
wizard.redoLastSpell(); wizard.redoLastSpell();
goblin.printStatus(); goblin.printStatus();
} }
} }

10
command/src/main/java/com/iluwatar/command/Command.java
View File

@ -7,13 +7,13 @@ package com.iluwatar.command;
*/ */
public abstract class Command { public abstract class Command {
public abstract void execute(Target target); public abstract void execute(Target target);
public abstract void undo(); public abstract void undo();
public abstract void redo(); public abstract void redo();
@Override @Override
public abstract String toString(); public abstract String toString();
} }

16
command/src/main/java/com/iluwatar/command/Goblin.java
View File

@ -7,14 +7,14 @@ package com.iluwatar.command;
*/ */
public class Goblin extends Target { public class Goblin extends Target {
public Goblin() { public Goblin() {
setSize(Size.NORMAL); setSize(Size.NORMAL);
setVisibility(Visibility.VISIBLE); setVisibility(Visibility.VISIBLE);
} }
@Override @Override
public String toString() { public String toString() {
return "Goblin"; return "Goblin";
} }
} }

44
command/src/main/java/com/iluwatar/command/InvisibilitySpell.java
View File

@ -7,30 +7,30 @@ package com.iluwatar.command;
*/ */
public class InvisibilitySpell extends Command { public class InvisibilitySpell extends Command {
private Target target; private Target target;
@Override @Override
public void execute(Target target) { public void execute(Target target) {
target.setVisibility(Visibility.INVISIBLE); target.setVisibility(Visibility.INVISIBLE);
this.target = target; this.target = target;
} }
@Override @Override
public void undo() { public void undo() {
if (target != null) { if (target != null) {
target.setVisibility(Visibility.VISIBLE); target.setVisibility(Visibility.VISIBLE);
} }
} }
@Override @Override
public void redo() { public void redo() {
if (target != null) { if (target != null) {
target.setVisibility(Visibility.INVISIBLE); target.setVisibility(Visibility.INVISIBLE);
} }
} }
@Override @Override
public String toString() { public String toString() {
return "Invisibility spell"; return "Invisibility spell";
} }
} }

48
command/src/main/java/com/iluwatar/command/ShrinkSpell.java
View File

@ -7,32 +7,32 @@ package com.iluwatar.command;
*/ */
public class ShrinkSpell extends Command { public class ShrinkSpell extends Command {
private Size oldSize; private Size oldSize;
private Target target; private Target target;
@Override @Override
public void execute(Target target) { public void execute(Target target) {
oldSize = target.getSize(); oldSize = target.getSize();
target.setSize(Size.SMALL); target.setSize(Size.SMALL);
this.target = target; this.target = target;
} }
@Override @Override
public void undo() { public void undo() {
if (oldSize != null && target != null) { if (oldSize != null && target != null) {
Size temp = target.getSize(); Size temp = target.getSize();
target.setSize(oldSize); target.setSize(oldSize);
oldSize = temp; oldSize = temp;
} }
} }
@Override @Override
public void redo() { public void redo() {
undo(); undo();
} }
@Override @Override
public String toString() { public String toString() {
return "Shrink spell"; return "Shrink spell";
} }
} }

20
command/src/main/java/com/iluwatar/command/Size.java
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@ -7,16 +7,16 @@ package com.iluwatar.command;
*/ */
public enum Size { public enum Size {
SMALL("small"), NORMAL("normal"), LARGE("large"), UNDEFINED(""); SMALL("small"), NORMAL("normal"), LARGE("large"), UNDEFINED("");
private String title;
Size(String title) { private String title;
this.title = title;
}
@Override Size(String title) {
public String toString() { this.title = title;
return title; }
}
@Override
public String toString() {
return title;
}
} }

42
command/src/main/java/com/iluwatar/command/Target.java
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@ -7,32 +7,32 @@ package com.iluwatar.command;
*/ */
public abstract class Target { public abstract class Target {
private Size size; private Size size;
private Visibility visibility; private Visibility visibility;
public Size getSize() { public Size getSize() {
return size; return size;
} }
public void setSize(Size size) { public void setSize(Size size) {
this.size = size; this.size = size;
} }
public Visibility getVisibility() { public Visibility getVisibility() {
return visibility; return visibility;
} }
public void setVisibility(Visibility visibility) { public void setVisibility(Visibility visibility) {
this.visibility = visibility; this.visibility = visibility;
} }
@Override @Override
public abstract String toString(); public abstract String toString();
public void printStatus() { public void printStatus() {
System.out.println(String.format("%s, [size=%s] [visibility=%s]", this, System.out.println(String.format("%s, [size=%s] [visibility=%s]", this, getSize(),
getSize(), getVisibility())); getVisibility()));
System.out.println(); System.out.println();
} }
} }

18
command/src/main/java/com/iluwatar/command/Visibility.java
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@ -7,16 +7,16 @@ package com.iluwatar.command;
*/ */
public enum Visibility { public enum Visibility {
VISIBLE("visible"), INVISIBLE("invisible"), UNDEFINED(""); VISIBLE("visible"), INVISIBLE("invisible"), UNDEFINED("");
private String title; private String title;
Visibility(String title) { Visibility(String title) {
this.title = title; this.title = title;
} }
@Override @Override
public String toString() { public String toString() {
return title; return title;
} }
} }

57
command/src/main/java/com/iluwatar/command/Wizard.java
View File

@ -10,38 +10,37 @@ import java.util.LinkedList;
*/ */
public class Wizard { public class Wizard {
private Deque<Command> undoStack = new LinkedList<>(); private Deque<Command> undoStack = new LinkedList<>();
private Deque<Command> redoStack = new LinkedList<>(); private Deque<Command> redoStack = new LinkedList<>();
public Wizard() { public Wizard() {}
}
public void castSpell(Command command, Target target) { public void castSpell(Command command, Target target) {
System.out.println(this + " casts " + command + " at " + target); System.out.println(this + " casts " + command + " at " + target);
command.execute(target); command.execute(target);
undoStack.offerLast(command); undoStack.offerLast(command);
} }
public void undoLastSpell() { public void undoLastSpell() {
if (!undoStack.isEmpty()) { if (!undoStack.isEmpty()) {
Command previousSpell = undoStack.pollLast(); Command previousSpell = undoStack.pollLast();
redoStack.offerLast(previousSpell); redoStack.offerLast(previousSpell);
System.out.println(this + " undoes " + previousSpell); System.out.println(this + " undoes " + previousSpell);
previousSpell.undo(); previousSpell.undo();
} }
} }
public void redoLastSpell() { public void redoLastSpell() {
if (!redoStack.isEmpty()) { if (!redoStack.isEmpty()) {
Command previousSpell = redoStack.pollLast(); Command previousSpell = redoStack.pollLast();
undoStack.offerLast(previousSpell); undoStack.offerLast(previousSpell);
System.out.println(this + " redoes " + previousSpell); System.out.println(this + " redoes " + previousSpell);
previousSpell.redo(); previousSpell.redo();
} }
} }
@Override @Override
public String toString() { public String toString() {
return "Wizard"; return "Wizard";
} }
} }

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

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

41
composite/src/main/java/com/iluwatar/composite/App.java
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@ -1,33 +1,34 @@
package com.iluwatar.composite; package com.iluwatar.composite;
/** /**
* The Composite pattern is a partitioning design pattern. The Composite pattern * The Composite pattern is a partitioning design pattern. The Composite pattern describes that a
* describes that a group of objects is to be treated in the same way as a single * group of objects is to be treated in the same way as a single instance of an object. The intent
* instance of an object. The intent of a composite is to "compose" objects into * of a composite is to "compose" objects into tree structures to represent part-whole hierarchies.
* tree structures to represent part-whole hierarchies. Implementing the Composite * Implementing the Composite pattern lets clients treat individual objects and compositions
* pattern lets clients treat individual objects and compositions uniformly. * uniformly.
* <p> * <p>
* In this example we have sentences composed of words composed of letters. All of * In this example we have sentences composed of words composed of letters. All of the objects can
* the objects can be treated through the same interface ({@link LetterComposite}). * be treated through the same interface ({@link LetterComposite}).
* *
*/ */
public class App { public class App {
/** /**
* Program entry point * Program entry point
* @param args command line args *
*/ * @param args command line args
public static void main(String[] args) { */
System.out.println("Message from the orcs: "); public static void main(String[] args) {
System.out.println("Message from the orcs: ");
LetterComposite orcMessage = new Messenger().messageFromOrcs(); LetterComposite orcMessage = new Messenger().messageFromOrcs();
orcMessage.print(); orcMessage.print();
System.out.println("\n"); System.out.println("\n");
System.out.println("Message from the elves: "); System.out.println("Message from the elves: ");
LetterComposite elfMessage = new Messenger().messageFromElves(); LetterComposite elfMessage = new Messenger().messageFromElves();
elfMessage.print(); elfMessage.print();
} }
} }

25
composite/src/main/java/com/iluwatar/composite/Letter.java
View File

@ -7,20 +7,19 @@ package com.iluwatar.composite;
*/ */
public class Letter extends LetterComposite { public class Letter extends LetterComposite {
private char c; private char c;
public Letter(char c) { public Letter(char c) {
this.c = c; this.c = c;
} }
@Override @Override
protected void printThisBefore() { protected void printThisBefore() {
System.out.print(c); System.out.print(c);
} }
@Override
protected void printThisAfter() {
// nop
}
@Override
protected void printThisAfter() {
// nop
}
} }

32
composite/src/main/java/com/iluwatar/composite/LetterComposite.java
View File

@ -10,25 +10,25 @@ import java.util.List;
*/ */
public abstract class LetterComposite { public abstract class LetterComposite {
private List<LetterComposite> children = new ArrayList<LetterComposite>(); private List<LetterComposite> children = new ArrayList<LetterComposite>();
public void add(LetterComposite letter) { public void add(LetterComposite letter) {
children.add(letter); children.add(letter);
} }
public int count() { public int count() {
return children.size(); return children.size();
} }
protected abstract void printThisBefore(); protected abstract void printThisBefore();
protected abstract void printThisAfter(); protected abstract void printThisAfter();
public void print() { public void print() {
printThisBefore(); printThisBefore();
for (LetterComposite letter : children) { for (LetterComposite letter : children) {
letter.print(); letter.print();
} }
printThisAfter(); printThisAfter();
} }
} }

67
composite/src/main/java/com/iluwatar/composite/Messenger.java
View File

@ -11,48 +11,47 @@ import java.util.List;
*/ */
public class Messenger { public class Messenger {
LetterComposite messageFromOrcs() { LetterComposite messageFromOrcs() {
List<Word> words = new ArrayList<Word>(); List<Word> words = new ArrayList<Word>();
words.add(new Word(Arrays.asList(new Letter('W'), new Letter('h'), words.add(new Word(Arrays.asList(new Letter('W'), new Letter('h'), new Letter('e'), new Letter(
new Letter('e'), new Letter('r'), new Letter('e')))); 'r'), new Letter('e'))));
words.add(new Word(Arrays.asList(new Letter('t'), new Letter('h'), words.add(new Word(Arrays.asList(new Letter('t'), new Letter('h'), new Letter('e'), new Letter(
new Letter('e'), new Letter('r'), new Letter('e')))); 'r'), new Letter('e'))));
words.add(new Word(Arrays.asList(new Letter('i'), new Letter('s')))); words.add(new Word(Arrays.asList(new Letter('i'), new Letter('s'))));
words.add(new Word(Arrays.asList(new Letter('a')))); words.add(new Word(Arrays.asList(new Letter('a'))));
words.add(new Word(Arrays.asList(new Letter('w'), new Letter('h'), words.add(new Word(Arrays.asList(new Letter('w'), new Letter('h'), new Letter('i'), new Letter(
new Letter('i'), new Letter('p')))); 'p'))));
words.add(new Word(Arrays.asList(new Letter('t'), new Letter('h'), words.add(new Word(Arrays.asList(new Letter('t'), new Letter('h'), new Letter('e'), new Letter(
new Letter('e'), new Letter('r'), new Letter('e')))); 'r'), new Letter('e'))));
words.add(new Word(Arrays.asList(new Letter('i'), new Letter('s')))); words.add(new Word(Arrays.asList(new Letter('i'), new Letter('s'))));
words.add(new Word(Arrays.asList(new Letter('a')))); words.add(new Word(Arrays.asList(new Letter('a'))));
words.add(new Word(Arrays.asList(new Letter('w'), new Letter('a'), words.add(new Word(Arrays.asList(new Letter('w'), new Letter('a'), new Letter('y'))));
new Letter('y'))));
return new Sentence(words); return new Sentence(words);
} }
LetterComposite messageFromElves() { LetterComposite messageFromElves() {
List<Word> words = new ArrayList<Word>(); List<Word> words = new ArrayList<Word>();
words.add(new Word(Arrays.asList(new Letter('M'), new Letter('u'), words.add(new Word(Arrays.asList(new Letter('M'), new Letter('u'), new Letter('c'), new Letter(
new Letter('c'), new Letter('h')))); 'h'))));
words.add(new Word(Arrays.asList(new Letter('w'), new Letter('i'), words.add(new Word(Arrays.asList(new Letter('w'), new Letter('i'), new Letter('n'), new Letter(
new Letter('n'), new Letter('d')))); 'd'))));
words.add(new Word(Arrays.asList(new Letter('p'), new Letter('o'), words.add(new Word(Arrays.asList(new Letter('p'), new Letter('o'), new Letter('u'), new Letter(
new Letter('u'), new Letter('r'), new Letter('s')))); 'r'), new Letter('s'))));
words.add(new Word(Arrays.asList(new Letter('f'), new Letter('r'), words.add(new Word(Arrays.asList(new Letter('f'), new Letter('r'), new Letter('o'), new Letter(
new Letter('o'), new Letter('m')))); 'm'))));
words.add(new Word(Arrays.asList(new Letter('y'), new Letter('o'), words.add(new Word(Arrays.asList(new Letter('y'), new Letter('o'), new Letter('u'), new Letter(
new Letter('u'), new Letter('r')))); 'r'))));
words.add(new Word(Arrays.asList(new Letter('m'), new Letter('o'), words.add(new Word(Arrays.asList(new Letter('m'), new Letter('o'), new Letter('u'), new Letter(
new Letter('u'), new Letter('t'), new Letter('h')))); 't'), new Letter('h'))));
return new Sentence(words); return new Sentence(words);
} }
} }

27
composite/src/main/java/com/iluwatar/composite/Sentence.java
View File

@ -9,20 +9,19 @@ import java.util.List;
*/ */
public class Sentence extends LetterComposite { public class Sentence extends LetterComposite {
public Sentence(List<Word> words) { public Sentence(List<Word> words) {
for (Word w : words) { for (Word w : words) {
this.add(w); this.add(w);
} }
} }
@Override @Override
protected void printThisBefore() { protected void printThisBefore() {
// nop // nop
} }
@Override
protected void printThisAfter() {
System.out.print(".");
}
@Override
protected void printThisAfter() {
System.out.print(".");
}
} }

27
composite/src/main/java/com/iluwatar/composite/Word.java
View File

@ -9,20 +9,19 @@ import java.util.List;
*/ */
public class Word extends LetterComposite { public class Word extends LetterComposite {
public Word(List<Letter> letters) { public Word(List<Letter> letters) {
for (Letter l : letters) { for (Letter l : letters) {
this.add(l); this.add(l);
} }
} }
@Override @Override
protected void printThisBefore() { protected void printThisBefore() {
System.out.print(" "); System.out.print(" ");
} }
@Override
protected void printThisAfter() {
// nop
}
@Override
protected void printThisAfter() {
// nop
}
} }

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

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

86
dao/src/main/java/com/iluwatar/dao/App.java
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@ -7,53 +7,55 @@ import org.apache.log4j.Logger;
/** /**
* *
* Data Access Object (DAO) is an object that provides an abstract interface to some type of database or other * Data Access Object (DAO) is an object that provides an abstract interface to some type of
* persistence mechanism. By mapping application calls to the persistence layer, DAO provide some specific data * database or other persistence mechanism. By mapping application calls to the persistence layer,
* operations without exposing details of the database. This isolation supports the Single responsibility principle. * DAO provide some specific data operations without exposing details of the database. This
* It separates what data accesses the application needs, in terms of domain-specific objects and data types * isolation supports the Single responsibility principle. It separates what data accesses the
* (the public interface of the DAO), from how these needs can be satisfied with a specific DBMS. * application needs, in terms of domain-specific objects and data types (the public interface of
* the DAO), from how these needs can be satisfied with a specific DBMS.
* <p> * <p>
* With the DAO pattern, we can use various method calls to retrieve/add/delete/update data without directly * With the DAO pattern, we can use various method calls to retrieve/add/delete/update data without
* interacting with the data. The below example demonstrates basic CRUD operations: select, add, update, and delete. * directly interacting with the data. The below example demonstrates basic CRUD operations: select,
* add, update, and delete.
* *
*/ */
public class App { public class App {
private static Logger LOGGER = Logger.getLogger(App.class); private static Logger LOGGER = Logger.getLogger(App.class);
/** /**
* Program entry point. * Program entry point.
* *
* @param args command line args. * @param args command line args.
*/ */
public static void main(final String[] args) { public static void main(final String[] args) {
final CustomerDaoImpl customerDao = new CustomerDaoImpl(generateSampleCustomers()); final CustomerDaoImpl customerDao = new CustomerDaoImpl(generateSampleCustomers());
LOGGER.info("customerDao.getAllCustomers(): " + customerDao.getAllCustomers()); LOGGER.info("customerDao.getAllCustomers(): " + customerDao.getAllCustomers());
LOGGER.info("customerDao.getCusterById(2): " + customerDao.getCustomerById(2)); LOGGER.info("customerDao.getCusterById(2): " + customerDao.getCustomerById(2));
final Customer customer = new Customer(4, "Dan", "Danson"); final Customer customer = new Customer(4, "Dan", "Danson");
customerDao.addCustomer(customer); customerDao.addCustomer(customer);
LOGGER.info("customerDao.getAllCustomers(): " + customerDao.getAllCustomers()); LOGGER.info("customerDao.getAllCustomers(): " + customerDao.getAllCustomers());
customer.setFirstName("Daniel"); customer.setFirstName("Daniel");
customer.setLastName("Danielson"); customer.setLastName("Danielson");
customerDao.updateCustomer(customer); customerDao.updateCustomer(customer);
LOGGER.info("customerDao.getAllCustomers(): " + customerDao.getAllCustomers()); LOGGER.info("customerDao.getAllCustomers(): " + customerDao.getAllCustomers());
customerDao.deleteCustomer(customer); customerDao.deleteCustomer(customer);
LOGGER.info("customerDao.getAllCustomers(): " + customerDao.getAllCustomers()); LOGGER.info("customerDao.getAllCustomers(): " + customerDao.getAllCustomers());
} }
/** /**
* Generate customers. * Generate customers.
* *
* @return list of customers. * @return list of customers.
*/ */
public static List<Customer> generateSampleCustomers() { public static List<Customer> generateSampleCustomers() {
final Customer customer1 = new Customer(1, "Adam", "Adamson"); final Customer customer1 = new Customer(1, "Adam", "Adamson");
final Customer customer2 = new Customer(2, "Bob", "Bobson"); final Customer customer2 = new Customer(2, "Bob", "Bobson");
final Customer customer3 = new Customer(3, "Carl", "Carlson"); final Customer customer3 = new Customer(3, "Carl", "Carlson");
final List<Customer> customers = new ArrayList<Customer>(); final List<Customer> customers = new ArrayList<Customer>();
customers.add(customer1); customers.add(customer1);
customers.add(customer2); customers.add(customer2);
customers.add(customer3); customers.add(customer3);
return customers; return customers;
} }
} }

52
decorator/src/main/java/com/iluwatar/decorator/App.java
View File

@ -2,37 +2,37 @@ package com.iluwatar.decorator;
/** /**
* *
* The Decorator pattern is a more flexible alternative to subclassing. The Decorator * The Decorator pattern is a more flexible alternative to subclassing. The Decorator class
* class implements the same interface as the target and uses composition to * implements the same interface as the target and uses composition to "decorate" calls to the
* "decorate" calls to the target. Using the Decorator pattern it is possible to * target. Using the Decorator pattern it is possible to change the behavior of the class during
* change the behavior of the class during runtime. * runtime.
* <p> * <p>
* In this example we show how the simple {@link Troll} first attacks and then * In this example we show how the simple {@link Troll} first attacks and then flees the battle.
* flees the battle. Then we decorate the {@link Troll} with a {@link SmartTroll} * Then we decorate the {@link Troll} with a {@link SmartTroll} and perform the attack again. You
* and perform the attack again. You can see how the behavior changes after the * can see how the behavior changes after the decoration.
* decoration.
* *
*/ */
public class App { public class App {
/** /**
* Program entry point * Program entry point
* @param args command line args *
*/ * @param args command line args
public static void main(String[] args) { */
public static void main(String[] args) {
// simple troll // simple troll
System.out.println("A simple looking troll approaches."); System.out.println("A simple looking troll approaches.");
Hostile troll = new Troll(); Hostile troll = new Troll();
troll.attack(); troll.attack();
troll.fleeBattle(); troll.fleeBattle();
System.out.printf("Simple troll power %d.\n", troll.getAttackPower()); System.out.printf("Simple troll power %d.\n", troll.getAttackPower());
// change the behavior of the simple troll by adding a decorator // change the behavior of the simple troll by adding a decorator
System.out.println("\nA smart looking troll surprises you."); System.out.println("\nA smart looking troll surprises you.");
Hostile smart = new SmartTroll(troll); Hostile smart = new SmartTroll(troll);
smart.attack(); smart.attack();
smart.fleeBattle(); smart.fleeBattle();
System.out.printf("Smart troll power %d.\n", smart.getAttackPower()); System.out.printf("Smart troll power %d.\n", smart.getAttackPower());
} }
} }

6
decorator/src/main/java/com/iluwatar/decorator/Hostile.java
View File

@ -7,10 +7,10 @@ package com.iluwatar.decorator;
*/ */
public interface Hostile { public interface Hostile {
void attack(); void attack();
int getAttackPower(); int getAttackPower();
void fleeBattle(); void fleeBattle();
} }

46
decorator/src/main/java/com/iluwatar/decorator/SmartTroll.java
View File

@ -1,36 +1,34 @@
package com.iluwatar.decorator; package com.iluwatar.decorator;
/** /**
* SmartTroll is a decorator for {@link Hostile} objects. * SmartTroll is a decorator for {@link Hostile} objects. The calls to the {@link Hostile} interface
* The calls to the {@link Hostile} interface are intercepted * are intercepted and decorated. Finally the calls are delegated to the decorated {@link Hostile}
* and decorated. Finally the calls are delegated * object.
* to the decorated {@link Hostile} object.
* *
*/ */
public class SmartTroll implements Hostile { public class SmartTroll implements Hostile {
private Hostile decorated; private Hostile decorated;
public SmartTroll(Hostile decorated) { public SmartTroll(Hostile decorated) {
this.decorated = decorated; this.decorated = decorated;
} }
@Override @Override
public void attack() { public void attack() {
System.out.println("The troll throws a rock at you!"); System.out.println("The troll throws a rock at you!");
decorated.attack(); decorated.attack();
} }
@Override @Override
public int getAttackPower() { public int getAttackPower() {
// decorated troll power + 20 because it is smart // decorated troll power + 20 because it is smart
return decorated.getAttackPower() + 20; return decorated.getAttackPower() + 20;
} }
@Override
public void fleeBattle() {
System.out.println("The troll calls for help!");
decorated.fleeBattle();
}
@Override
public void fleeBattle() {
System.out.println("The troll calls for help!");
decorated.fleeBattle();
}
} }

21
decorator/src/main/java/com/iluwatar/decorator/Troll.java
View File

@ -7,17 +7,16 @@ package com.iluwatar.decorator;
*/ */
public class Troll implements Hostile { public class Troll implements Hostile {
public void attack() { public void attack() {
System.out.println("The troll swings at you with a club!"); System.out.println("The troll swings at you with a club!");
} }
@Override @Override
public int getAttackPower() { public int getAttackPower() {
return 10; return 10;
} }
public void fleeBattle() {
System.out.println("The troll shrieks in horror and runs away!");
}
public void fleeBattle() {
System.out.println("The troll shrieks in horror and runs away!");
}
} }

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

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

23
dependency-injection/src/main/java/com/iluwatar/dependency/injection/AdvancedWizard.java
View File

@ -2,21 +2,20 @@ package com.iluwatar.dependency.injection;
/** /**
* *
* AdvancedWizard implements inversion of control. * AdvancedWizard implements inversion of control. It depends on abstraction that can be injected
* It depends on abstraction that can be injected through * through its constructor.
* its constructor.
* *
*/ */
public class AdvancedWizard implements Wizard { public class AdvancedWizard implements Wizard {
private Tobacco tobacco;
public AdvancedWizard(Tobacco tobacco) { private Tobacco tobacco;
this.tobacco = tobacco;
}
@Override public AdvancedWizard(Tobacco tobacco) {
public void smoke() { this.tobacco = tobacco;
tobacco.smoke(this); }
}
@Override
public void smoke() {
tobacco.smoke(this);
}
} }

65
dependency-injection/src/main/java/com/iluwatar/dependency/injection/App.java
View File

@ -5,40 +5,41 @@ import com.google.inject.Injector;
/** /**
* *
* Dependency Injection pattern deals with how objects handle their dependencies. The pattern * Dependency Injection pattern deals with how objects handle their dependencies. The pattern
* implements so called inversion of control principle. Inversion of control has two specific rules: * implements so called inversion of control principle. Inversion of control has two specific rules:
* - High-level modules should not depend on low-level modules. Both should depend on abstractions. * - High-level modules should not depend on low-level modules. Both should depend on abstractions.
* - Abstractions should not depend on details. Details should depend on abstractions. * - Abstractions should not depend on details. Details should depend on abstractions.
* <p> * <p>
* In this example we show you three different wizards. The first one ({@link SimpleWizard}) is a naive * In this example we show you three different wizards. The first one ({@link SimpleWizard}) is a
* implementation violating the inversion of control principle. It depends directly on a concrete * naive implementation violating the inversion of control principle. It depends directly on a
* implementation which cannot be changed. * concrete implementation which cannot be changed.
* <p> * <p>
* The second wizard ({@link AdvancedWizard}) is more flexible. It does not depend on any concrete implementation * The second wizard ({@link AdvancedWizard}) is more flexible. It does not depend on any concrete
* but abstraction. It utilizes Dependency Injection pattern allowing its {@link Tobacco} dependency to be * implementation but abstraction. It utilizes Dependency Injection pattern allowing its
* injected through its constructor. This way, handling the dependency is no longer the wizard's * {@link Tobacco} dependency to be injected through its constructor. This way, handling the
* responsibility. It is resolved outside the wizard class. * dependency is no longer the wizard's responsibility. It is resolved outside the wizard class.
* <p> * <p>
* The third example takes the pattern a step further. It uses Guice framework for Dependency Injection. * The third example takes the pattern a step further. It uses Guice framework for Dependency
* {@link TobaccoModule} binds a concrete implementation to abstraction. Injector is then used to create * Injection. {@link TobaccoModule} binds a concrete implementation to abstraction. Injector is then
* {@link GuiceWizard} object with correct dependencies. * used to create {@link GuiceWizard} object with correct dependencies.
* *
*/ */
public class App { public class App {
/** /**
* Program entry point * Program entry point
* @param args command line args *
*/ * @param args command line args
public static void main( String[] args ) { */
SimpleWizard simpleWizard = new SimpleWizard(); public static void main(String[] args) {
simpleWizard.smoke(); SimpleWizard simpleWizard = new SimpleWizard();
simpleWizard.smoke();
AdvancedWizard advancedWizard = new AdvancedWizard(new SecondBreakfastTobacco());
advancedWizard.smoke(); AdvancedWizard advancedWizard = new AdvancedWizard(new SecondBreakfastTobacco());
advancedWizard.smoke();
Injector injector = Guice.createInjector(new TobaccoModule());
GuiceWizard guiceWizard = injector.getInstance(GuiceWizard.class); Injector injector = Guice.createInjector(new TobaccoModule());
guiceWizard.smoke(); GuiceWizard guiceWizard = injector.getInstance(GuiceWizard.class);
} guiceWizard.smoke();
}
} }

27
dependency-injection/src/main/java/com/iluwatar/dependency/injection/GuiceWizard.java
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@ -4,22 +4,21 @@ import javax.inject.Inject;
/** /**
* *
* GuiceWizard implements inversion of control. * GuiceWizard implements inversion of control. Its dependencies are injected through its
* Its dependencies are injected through its constructor * constructor by Guice framework.
* by Guice framework.
* *
*/ */
public class GuiceWizard implements Wizard { public class GuiceWizard implements Wizard {
private Tobacco tobacco;
@Inject
public GuiceWizard(Tobacco tobacco) {
this.tobacco = tobacco;
}
@Override private Tobacco tobacco;
public void smoke() {
tobacco.smoke(this); @Inject
} public GuiceWizard(Tobacco tobacco) {
this.tobacco = tobacco;
}
@Override
public void smoke() {
tobacco.smoke(this);
}
} }

16
dependency-injection/src/main/java/com/iluwatar/dependency/injection/SimpleWizard.java
View File

@ -2,15 +2,15 @@ package com.iluwatar.dependency.injection;
/** /**
* *
* Naive Wizard implementation violating the inversion of control principle. * Naive Wizard implementation violating the inversion of control principle. It should depend on
* It should depend on abstraction instead. * abstraction instead.
* *
*/ */
public class SimpleWizard implements Wizard { public class SimpleWizard implements Wizard {
private OldTobyTobacco tobacco = new OldTobyTobacco(); private OldTobyTobacco tobacco = new OldTobyTobacco();
public void smoke() { public void smoke() {
tobacco.smoke(this); tobacco.smoke(this);
} }
} }

9
dependency-injection/src/main/java/com/iluwatar/dependency/injection/Tobacco.java
View File

@ -6,8 +6,9 @@ package com.iluwatar.dependency.injection;
* *
*/ */
public abstract class Tobacco { public abstract class Tobacco {
public void smoke(Wizard wizard) { public void smoke(Wizard wizard) {
System.out.println(String.format("%s smoking %s", wizard.getClass().getSimpleName(), this.getClass().getSimpleName())); System.out.println(String.format("%s smoking %s", wizard.getClass().getSimpleName(), this
} .getClass().getSimpleName()));
}
} }

8
dependency-injection/src/main/java/com/iluwatar/dependency/injection/TobaccoModule.java
View File

@ -9,8 +9,8 @@ import com.google.inject.AbstractModule;
*/ */
public class TobaccoModule extends AbstractModule { public class TobaccoModule extends AbstractModule {
@Override @Override
protected void configure() { protected void configure() {
bind(Tobacco.class).to(RivendellTobacco.class); bind(Tobacco.class).to(RivendellTobacco.class);
} }
} }

4
dependency-injection/src/main/java/com/iluwatar/dependency/injection/Wizard.java
View File

@ -6,7 +6,7 @@ package com.iluwatar.dependency.injection;
* *
*/ */
public interface Wizard { public interface Wizard {
void smoke(); void smoke();
} }

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