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Resolves checkstyle errors for remaining m (#1090)

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* Reduces checkstyle errors in marker

* Reduces checkstyle errors in master-worker-pattern

* Reduces checkstyle errors in mediator

* Reduces checkstyle errors in memento

* Reduces checkstyle errors in model-view-controller

* Reduces checkstyle errors in model-view-presenter

* Reduces checkstyle errors in module

* Reduces checkstyle errors in monad

* Reduces checkstyle errors in monostate

* Reduces checkstyle errors in multiton

* Reduces checkstyle errors in mute-idiom

* Reduces checkstyle errors in mutex
This commit is contained in:
Anurag Agarwal 2019-11-16 18:18:23 +05:30 committed by Ilkka Seppälä
parent 3ccc9baa1a
commit 1fdc650545
66 changed files with 374 additions and 423 deletions
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30
marker/src/main/java/App.java
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@ -25,27 +25,23 @@ import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* Created by Alexis on 28-Apr-17.
* With Marker interface idea is to make empty interface and extend it.
* Basically it is just to identify the special objects from normal objects.
* Like in case of serialization , objects that need to be serialized must implement serializable interface
* (it is empty interface) and down the line writeObject() method must be checking
* if it is a instance of serializable or not.
* <p>
* Marker interface vs annotation
* Marker interfaces and marker annotations both have their uses,
* neither of them is obsolete or always better then the other one.
* If you want to define a type that does not have any new methods associated with it,
* a marker interface is the way to go.
* If you want to mark program elements other than classes and interfaces,
* to allow for the possibility of adding more information to the marker in the future,
* or to fit the marker into a framework that already makes heavy use of annotation types,
* then a marker annotation is the correct choice
* Created by Alexis on 28-Apr-17. With Marker interface idea is to make empty interface and extend
* it. Basically it is just to identify the special objects from normal objects. Like in case of
* serialization , objects that need to be serialized must implement serializable interface (it is
* empty interface) and down the line writeObject() method must be checking if it is a instance of
* serializable or not.
*
* <p>Marker interface vs annotation Marker interfaces and marker annotations both have their uses,
* neither of them is obsolete or always better then the other one. If you want to define a type
* that does not have any new methods associated with it, a marker interface is the way to go. If
* you want to mark program elements other than classes and interfaces, to allow for the possibility
* of adding more information to the marker in the future, or to fit the marker into a framework
* that already makes heavy use of annotation types, then a marker annotation is the correct choice
*/
public class App {
/**
* Program entry point
* Program entry point.
*
* @param args command line args
*/

2
marker/src/main/java/Guard.java
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@ -25,7 +25,7 @@ import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* Class defining Guard
* Class defining Guard.
*/
public class Guard implements Permission {

3
marker/src/main/java/Permission.java
View File

@ -22,8 +22,7 @@
*/
/**
* Interface without any methods
* Marker interface is based on that assumption
* Interface without any methods Marker interface is based on that assumption.
*/
public interface Permission {
}

2
marker/src/main/java/Thief.java
View File

@ -25,7 +25,7 @@ import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* Class defining Thief
* Class defining Thief.
*/
public class Thief {

45
master-worker-pattern/src/main/java/com/iluwatar/masterworker/App.java
View File

@ -28,30 +28,37 @@ import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* <p>The <b><em>Master-Worker</em></b> pattern is used when the problem at hand can be solved by dividing into
* multiple parts which need to go through the same computation and may need to be aggregated to get final result.
* Parallel processing is performed using a system consisting of a master and some number of workers, where a
* master divides the work among the workers, gets the result back from them and assimilates all the results to
* give final result. The only communication is between the master and the worker - none of the workers communicate
* among one another and the user only communicates with the master to get required job done.</p>
* <p>In our example, we have generic abstract classes {@link MasterWorker}, {@link Master} and {@link Worker} which
* have to be extended by the classes which will perform the specific job at hand (in this case finding transpose of
* matrix, done by {@link ArrayTransposeMasterWorker}, {@link ArrayTransposeMaster} and {@link ArrayTransposeWorker}).
* The Master class divides the work into parts to be given to the workers, collects the results from the workers and
* aggregates it when all workers have responded before returning the solution. The Worker class extends the Thread
* class to enable parallel processing, and does the work once the data has been received from the Master. The
* MasterWorker contains a reference to the Master class, gets the input from the App and passes it on to the Master.
* These 3 classes define the system which computes the result. We also have 2 abstract classes {@link Input} and
* {@link Result}, which contain the input data and result data respectively. The Input class also has an abstract
* method divideData which defines how the data is to be divided into segments. These classes are extended by
* {@link ArrayInput} and {@link ArrayResult}.</p>
* <p>The <b><em>Master-Worker</em></b> pattern is used when the problem at hand can be solved by
* dividing into
* multiple parts which need to go through the same computation and may need to be aggregated to get
* final result. Parallel processing is performed using a system consisting of a master and some
* number of workers, where a master divides the work among the workers, gets the result back from
* them and assimilates all the results to give final result. The only communication is between the
* master and the worker - none of the workers communicate among one another and the user only
* communicates with the master to get required job done.</p>
* <p>In our example, we have generic abstract classes {@link MasterWorker}, {@link Master} and
* {@link Worker} which
* have to be extended by the classes which will perform the specific job at hand (in this case
* finding transpose of matrix, done by {@link ArrayTransposeMasterWorker}, {@link
* ArrayTransposeMaster} and {@link ArrayTransposeWorker}). The Master class divides the work into
* parts to be given to the workers, collects the results from the workers and aggregates it when
* all workers have responded before returning the solution. The Worker class extends the Thread
* class to enable parallel processing, and does the work once the data has been received from the
* Master. The MasterWorker contains a reference to the Master class, gets the input from the App
* and passes it on to the Master. These 3 classes define the system which computes the result. We
* also have 2 abstract classes {@link Input} and {@link Result}, which contain the input data and
* result data respectively. The Input class also has an abstract method divideData which defines
* how the data is to be divided into segments. These classes are extended by {@link ArrayInput} and
* {@link ArrayResult}.</p>
*/
public class App {
private static final Logger LOGGER = LoggerFactory.getLogger(App.class);
/**
* Program entry point.
*
* @param args command line args
*/
@ -59,9 +66,9 @@ public class App {
ArrayTransposeMasterWorker mw = new ArrayTransposeMasterWorker();
int rows = 10;
int columns = 20;
int[][] inputMatrix = ArrayUtilityMethods.createRandomIntMatrix(rows,columns);
int[][] inputMatrix = ArrayUtilityMethods.createRandomIntMatrix(rows, columns);
ArrayInput input = new ArrayInput(inputMatrix);
ArrayResult result = (ArrayResult) mw.getResult(input);
ArrayResult result = (ArrayResult) mw.getResult(input);
if (result != null) {
ArrayUtilityMethods.printMatrix(inputMatrix);
ArrayUtilityMethods.printMatrix(result.data);

9
master-worker-pattern/src/main/java/com/iluwatar/masterworker/ArrayInput.java
View File

@ -27,8 +27,7 @@ import java.util.ArrayList;
import java.util.Arrays;
/**
*Class ArrayInput extends abstract class {@link Input} and contains data
*of type int[][].
* Class ArrayInput extends abstract class {@link Input} and contains data of type int[][].
*/
public class ArrayInput extends Input<int[][]> {
@ -36,7 +35,7 @@ public class ArrayInput extends Input<int[][]> {
public ArrayInput(int[][] data) {
super(data);
}
static int[] makeDivisions(int[][] data, int num) {
int initialDivision = data.length / num; //equally dividing
int[] divisions = new int[num];
@ -81,6 +80,6 @@ public class ArrayInput extends Input<int[][]> {
}
}
return result;
}
}
}
}
}

3
master-worker-pattern/src/main/java/com/iluwatar/masterworker/ArrayResult.java
View File

@ -24,8 +24,7 @@
package com.iluwatar.masterworker;
/**
*Class ArrayResult extends abstract class {@link Result} and contains data
*of type int[][].
* Class ArrayResult extends abstract class {@link Result} and contains data of type int[][].
*/
public class ArrayResult extends Result<int[][]> {

32
master-worker-pattern/src/main/java/com/iluwatar/masterworker/ArrayUtilityMethods.java
View File

@ -23,23 +23,23 @@
package com.iluwatar.masterworker;
import java.util.Random;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.util.Random;
/**
*Class ArrayUtilityMethods has some utility methods for matrices and arrays.
* Class ArrayUtilityMethods has some utility methods for matrices and arrays.
*/
public class ArrayUtilityMethods {
private static final Logger LOGGER = LoggerFactory.getLogger(ArrayUtilityMethods.class);
private static final Random RANDOM = new Random();
/**
* Method arraysSame compares 2 arrays @param a1 and @param a2
* and @return whether their values are equal (boolean).
* Method arraysSame compares 2 arrays @param a1 and @param a2 and @return whether their values
* are equal (boolean).
*/
public static boolean arraysSame(int[] a1, int[] a2) {
@ -61,10 +61,10 @@ public class ArrayUtilityMethods {
}
/**
* Method matricesSame compares 2 matrices @param m1 and @param m2
* and @return whether their values are equal (boolean).
* Method matricesSame compares 2 matrices @param m1 and @param m2 and @return whether their
* values are equal (boolean).
*/
public static boolean matricesSame(int[][] m1, int[][] m2) {
if (m1.length != m2.length) {
return false;
@ -81,12 +81,12 @@ public class ArrayUtilityMethods {
return answer;
}
}
/**
* Method createRandomIntMatrix creates a random matrix of size @param rows
* and @param columns @return it (int[][]).
* Method createRandomIntMatrix creates a random matrix of size @param rows and @param columns.
*
* @return it (int[][]).
*/
public static int[][] createRandomIntMatrix(int rows, int columns) {
int[][] matrix = new int[rows][columns];
for (int i = 0; i < rows; i++) {
@ -97,11 +97,11 @@ public class ArrayUtilityMethods {
}
return matrix;
}
/**
* Method printMatrix prints input matrix @param matrix.
*/
public static void printMatrix(int[][] matrix) {
//prints out int[][]
for (int i = 0; i < matrix.length; i++) {
@ -111,5 +111,5 @@ public class ArrayUtilityMethods {
LOGGER.info("");
}
}
}

11
master-worker-pattern/src/main/java/com/iluwatar/masterworker/Input.java
View File

@ -26,18 +26,19 @@ package com.iluwatar.masterworker;
import java.util.ArrayList;
/**
*The abstract Input class, having 1 public field which contains input data,
*and abstract method divideData.
* The abstract Input class, having 1 public field which contains input data, and abstract method
* divideData.
*
* @param <T> T will be type of data.
*/
public abstract class Input<T> {
public final T data;
public Input(T data) {
this.data = data;
}
public abstract ArrayList<Input> divideData(int num);
}

6
master-worker-pattern/src/main/java/com/iluwatar/masterworker/Result.java
View File

@ -24,13 +24,13 @@
package com.iluwatar.masterworker;
/**
*The abstract Result class, which contains 1 public field containing result
*data.
* The abstract Result class, which contains 1 public field containing result data.
*
* @param <T> T will be type of data.
*/
public abstract class Result<T> {
public final T data;
public Result(T data) {

4
master-worker-pattern/src/main/java/com/iluwatar/masterworker/system/ArrayTransposeMasterWorker.java
View File

@ -27,8 +27,8 @@ import com.iluwatar.masterworker.system.systemmaster.ArrayTransposeMaster;
import com.iluwatar.masterworker.system.systemmaster.Master;
/**
*Class ArrayTransposeMasterWorker extends abstract class {@link MasterWorker} and
*specifically solves the problem of finding transpose of input array.
* Class ArrayTransposeMasterWorker extends abstract class {@link MasterWorker} and specifically
* solves the problem of finding transpose of input array.
*/
public class ArrayTransposeMasterWorker extends MasterWorker {

2
master-worker-pattern/src/main/java/com/iluwatar/masterworker/system/MasterWorker.java
View File

@ -28,7 +28,7 @@ import com.iluwatar.masterworker.Result;
import com.iluwatar.masterworker.system.systemmaster.Master;
/**
*The abstract MasterWorker class which contains reference to master.
* The abstract MasterWorker class which contains reference to master.
*/
public abstract class MasterWorker {

28
master-worker-pattern/src/main/java/com/iluwatar/masterworker/system/systemmaster/ArrayTransposeMaster.java
View File

@ -23,16 +23,15 @@
package com.iluwatar.masterworker.system.systemmaster;
import java.util.ArrayList;
import java.util.Enumeration;
import com.iluwatar.masterworker.ArrayResult;
import com.iluwatar.masterworker.system.systemworkers.ArrayTransposeWorker;
import com.iluwatar.masterworker.system.systemworkers.Worker;
import java.util.ArrayList;
import java.util.Enumeration;
/**
*Class ArrayTransposeMaster extends abstract class {@link Master} and contains
*definition of aggregateData, which will obtain final result from all
*data obtained and for setWorkers.
* Class ArrayTransposeMaster extends abstract class {@link Master} and contains definition of
* aggregateData, which will obtain final result from all data obtained and for setWorkers.
*/
public class ArrayTransposeMaster extends Master {
@ -43,26 +42,29 @@ public class ArrayTransposeMaster extends Master {
@Override
ArrayList<Worker> setWorkers(int num) {
ArrayList<Worker> ws = new ArrayList<Worker>(num);
for (int i = 0; i < num ; i++) {
for (int i = 0; i < num; i++) {
ws.add(new ArrayTransposeWorker(this, i + 1));
//i+1 will be id
}
return ws;
}
@Override
ArrayResult aggregateData() {
//number of rows in final result is number of rows in any of obtained results obtained from workers
int rows = ((ArrayResult) this.getAllResultData().get(this.getAllResultData().keys().nextElement())).data.length;
int columns = 0; //number of columns is sum of number of columns in all results obtained from workers
for (Enumeration<Integer> e = this.getAllResultData().keys(); e.hasMoreElements();) {
// number of rows in final result is number of rows in any of obtained results from workers
int rows = ((ArrayResult) this.getAllResultData()
.get(this.getAllResultData().keys().nextElement())).data.length;
int columns =
0; //number of columns is sum of number of columns in all results obtained from workers
for (Enumeration<Integer> e = this.getAllResultData().keys(); e.hasMoreElements(); ) {
columns += ((ArrayResult) this.getAllResultData().get(e.nextElement())).data[0].length;
}
int[][] resultData = new int[rows][columns];
int columnsDone = 0; //columns aggregated so far
for (int i = 0; i < this.getExpectedNumResults(); i++) {
//result obtained from ith worker
int[][] work = ((ArrayResult) this.getAllResultData().get(this.getWorkers().get(i).getWorkerId())).data;
int[][] work =
((ArrayResult) this.getAllResultData().get(this.getWorkers().get(i).getWorkerId())).data;
for (int m = 0; m < work.length; m++) {
//m = row number, n = columns number
for (int n = 0; n < work[0].length; n++) {
@ -73,5 +75,5 @@ public class ArrayTransposeMaster extends Master {
}
return new ArrayResult(resultData);
}
}

37
master-worker-pattern/src/main/java/com/iluwatar/masterworker/system/systemmaster/Master.java
View File

@ -23,18 +23,17 @@
package com.iluwatar.masterworker.system.systemmaster;
import java.util.ArrayList;
import java.util.Hashtable;
import com.iluwatar.masterworker.Input;
import com.iluwatar.masterworker.Result;
import com.iluwatar.masterworker.system.systemworkers.Worker;
import java.util.ArrayList;
import java.util.Hashtable;
/**
*The abstract Master class which contains private fields numOfWorkers
*(number of workers), workers (arraylist of workers), expectedNumResults
*(number of divisions of input data, same as expected number of results),
*allResultData (hashtable of results obtained from workers, mapped by
*their ids) and finalResult (aggregated from allResultData).
* The abstract Master class which contains private fields numOfWorkers (number of workers), workers
* (arraylist of workers), expectedNumResults (number of divisions of input data, same as expected
* number of results), allResultData (hashtable of results obtained from workers, mapped by their
* ids) and finalResult (aggregated from allResultData).
*/
public abstract class Master {
@ -43,7 +42,7 @@ public abstract class Master {
private int expectedNumResults;
private Hashtable<Integer, Result> allResultData;
private Result finalResult;
Master(int numOfWorkers) {
this.numOfWorkers = numOfWorkers;
this.workers = setWorkers(numOfWorkers);
@ -51,46 +50,46 @@ public abstract class Master {
this.allResultData = new Hashtable<Integer, Result>(numOfWorkers);
this.finalResult = null;
}
public Result getFinalResult() {
return this.finalResult;
}
Hashtable<Integer, Result> getAllResultData() {
return this.allResultData;
}
int getExpectedNumResults() {
return this.expectedNumResults;
}
ArrayList<Worker> getWorkers() {
return this.workers;
}
abstract ArrayList<Worker> setWorkers(int num);
public void doWork(Input input) {
divideWork(input);
}
private void divideWork(Input input) {
ArrayList<Input> dividedInput = input.divideData(numOfWorkers);
if (dividedInput != null) {
this.expectedNumResults = dividedInput.size();
for (int i = 0; i < this.expectedNumResults; i++) {
for (int i = 0; i < this.expectedNumResults; i++) {
//ith division given to ith worker in this.workers
this.workers.get(i).setReceivedData(this, dividedInput.get(i));
this.workers.get(i).run();
}
}
}
public void receiveData(Result data, Worker w) {
//check if can receive..if yes:
collectResult(data, w.getWorkerId());
}
private void collectResult(Result data, int workerId) {
this.allResultData.put(workerId, data);
if (this.allResultData.size() == this.expectedNumResults) {
@ -98,6 +97,6 @@ public abstract class Master {
this.finalResult = aggregateData();
}
}
abstract Result aggregateData();
}

16
master-worker-pattern/src/main/java/com/iluwatar/masterworker/system/systemworkers/ArrayTransposeWorker.java
View File

@ -28,8 +28,8 @@ import com.iluwatar.masterworker.ArrayResult;
import com.iluwatar.masterworker.system.systemmaster.Master;
/**
*Class ArrayTransposeWorker extends abstract class {@link Worker} and defines method
*executeOperation(), to be performed on data received from master.
* Class ArrayTransposeWorker extends abstract class {@link Worker} and defines method
* executeOperation(), to be performed on data received from master.
*/
public class ArrayTransposeWorker extends Worker {
@ -41,12 +41,14 @@ public class ArrayTransposeWorker extends Worker {
@Override
ArrayResult executeOperation() {
//number of rows in result matrix is equal to number of columns in input matrix and vice versa
int[][] resultData = new int[((ArrayInput) this.getReceivedData()).data[0].length]
[((ArrayInput) this.getReceivedData()).data.length];
for (int i = 0; i < ((ArrayInput) this.getReceivedData()).data.length; i++) {
for (int j = 0; j < ((ArrayInput) this.getReceivedData()).data[0].length; j++) {
ArrayInput arrayInput = (ArrayInput) this.getReceivedData();
final int rows = arrayInput.data[0].length;
final int cols = arrayInput.data.length;
int[][] resultData = new int[rows][cols];
for (int i = 0; i < cols; i++) {
for (int j = 0; j < rows; j++) {
//flipping element positions along diagonal
resultData[j][i] = ((ArrayInput) this.getReceivedData()).data[i][j];
resultData[j][i] = arrayInput.data[i][j];
}
}
return new ArrayResult(resultData);

7
master-worker-pattern/src/main/java/com/iluwatar/masterworker/system/systemworkers/Worker.java
View File

@ -28,9 +28,8 @@ import com.iluwatar.masterworker.Result;
import com.iluwatar.masterworker.system.systemmaster.Master;
/**
*The abstract Worker class which extends Thread class to enable parallel
*processing. Contains fields master(holding reference to master), workerId
*(unique id) and receivedData(from master).
* The abstract Worker class which extends Thread class to enable parallel processing. Contains
* fields master(holding reference to master), workerId (unique id) and receivedData(from master).
*/
public abstract class Worker extends Thread {
@ -61,7 +60,7 @@ public abstract class Worker extends Thread {
private void sendToMaster(Result data) {
this.master.receiveData(data, this);
}
}
public void run() { //from Thread class
Result work = executeOperation();

10
mediator/src/main/java/com/iluwatar/mediator/Action.java
View File

@ -24,15 +24,15 @@
package com.iluwatar.mediator;
/**
*
* Action enumeration.
*
*/
public enum Action {
HUNT("hunted a rabbit", "arrives for dinner"), TALE("tells a tale", "comes to listen"), GOLD(
"found gold", "takes his share of the gold"), ENEMY("spotted enemies", "runs for cover"), NONE(
"", "");
HUNT("hunted a rabbit", "arrives for dinner"),
TALE("tells a tale", "comes to listen"),
GOLD("found gold", "takes his share of the gold"),
ENEMY("spotted enemies", "runs for cover"),
NONE("", "");
private String title;
private String description;

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

@ -24,32 +24,31 @@
package com.iluwatar.mediator;
/**
*
* The Mediator pattern defines an object that encapsulates how a set of objects interact. This
* pattern is considered to be a behavioral pattern due to the way it can alter the program's
* running behavior.
* <p>
* Usually a program is made up of a large number of classes. So the logic and computation is
*
* <p>Usually a program is made up of a large number of classes. So the logic and computation is
* distributed among these classes. However, as more classes are developed in a program, especially
* during maintenance and/or refactoring, the problem of communication between these classes may
* become more complex. This makes the program harder to read and maintain. Furthermore, it can
* become difficult to change the program, since any change may affect code in several other
* classes.
* <p>
* With the Mediator pattern, communication between objects is encapsulated with a mediator object.
* Objects no longer communicate directly with each other, but instead communicate through the
* mediator. This reduces the dependencies between communicating objects, thereby lowering the
*
* <p>With the Mediator pattern, communication between objects is encapsulated with a mediator
* object. Objects no longer communicate directly with each other, but instead communicate through
* the mediator. This reduces the dependencies between communicating objects, thereby lowering the
* coupling.
* <p>
* In this example the mediator encapsulates how a set of objects ({@link PartyMember}) interact.
* Instead of referring to each other directly they use the mediator ({@link Party}) interface.
*
*
* <p>In this example the mediator encapsulates how a set of objects ({@link PartyMember})
* interact. Instead of referring to each other directly they use the mediator ({@link Party})
* interface.
*/
public class App {
/**
* Program entry point
*
* Program entry point.
*
* @param args command line args
*/
public static void main(String[] args) {

2
mediator/src/main/java/com/iluwatar/mediator/Hobbit.java
View File

@ -24,9 +24,7 @@
package com.iluwatar.mediator;
/**
*
* Hobbit party member.
*
*/
public class Hobbit extends PartyMemberBase {

2
mediator/src/main/java/com/iluwatar/mediator/Hunter.java
View File

@ -24,9 +24,7 @@
package com.iluwatar.mediator;
/**
*
* Hunter party member.
*
*/
public class Hunter extends PartyMemberBase {

2
mediator/src/main/java/com/iluwatar/mediator/Party.java
View File

@ -24,9 +24,7 @@
package com.iluwatar.mediator;
/**
*
* Party interface.
*
*/
public interface Party {

2
mediator/src/main/java/com/iluwatar/mediator/PartyImpl.java
View File

@ -27,9 +27,7 @@ import java.util.ArrayList;
import java.util.List;
/**
*
* Party implementation.
*
*/
public class PartyImpl implements Party {

2
mediator/src/main/java/com/iluwatar/mediator/PartyMember.java
View File

@ -24,9 +24,7 @@
package com.iluwatar.mediator;
/**
*
* Interface for party members interacting with {@link Party}.
*
*/
public interface PartyMember {

2
mediator/src/main/java/com/iluwatar/mediator/PartyMemberBase.java
View File

@ -27,9 +27,7 @@ import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
*
* Abstract base class for party members.
*
*/
public abstract class PartyMemberBase implements PartyMember {

2
mediator/src/main/java/com/iluwatar/mediator/Rogue.java
View File

@ -24,9 +24,7 @@
package com.iluwatar.mediator;
/**
*
* Rogue party member.
*
*/
public class Rogue extends PartyMemberBase {

2
mediator/src/main/java/com/iluwatar/mediator/Wizard.java
View File

@ -24,9 +24,7 @@
package com.iluwatar.mediator;
/**
*
* Wizard party member.
*
*/
public class Wizard extends PartyMemberBase {

29
memento/src/main/java/com/iluwatar/memento/App.java
View File

@ -23,36 +23,33 @@
package com.iluwatar.memento;
import java.util.Stack;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.util.Stack;
/**
*
* The Memento pattern is a software design pattern that provides the ability to restore an object
* to its previous state (undo via rollback).
* <p>
* The Memento pattern is implemented with three objects: the originator, a caretaker and a memento.
* The originator is some object that has an internal state. The caretaker is going to do something
* to the originator, but wants to be able to undo the change. The caretaker first asks the
* originator for a memento object. Then it does whatever operation (or sequence of operations) it
* was going to do. To roll back to the state before the operations, it returns the memento object
* to the originator. The memento object itself is an opaque object (one which the caretaker cannot,
* or should not, change). When using this pattern, care should be taken if the originator may
* change other objects or resources - the memento pattern operates on a single object.
* <p>
* In this example the object ({@link Star}) gives out a "memento" ({@link StarMemento}) that
*
* <p>The Memento pattern is implemented with three objects: the originator, a caretaker and a
* memento. The originator is some object that has an internal state. The caretaker is going to do
* something to the originator, but wants to be able to undo the change. The caretaker first asks
* the originator for a memento object. Then it does whatever operation (or sequence of operations)
* it was going to do. To roll back to the state before the operations, it returns the memento
* object to the originator. The memento object itself is an opaque object (one which the caretaker
* cannot, or should not, change). When using this pattern, care should be taken if the originator
* may change other objects or resources - the memento pattern operates on a single object.
*
* <p>In this example the object ({@link Star}) gives out a "memento" ({@link StarMemento}) that
* contains the state of the object. Later on the memento can be set back to the object restoring
* the state.
*
*/
public class App {
private static final Logger LOGGER = LoggerFactory.getLogger(App.class);
/**
* Program entry point
* Program entry point.
*/
public static void main(String[] args) {
Stack<StarMemento> states = new Stack<>();

10
memento/src/main/java/com/iluwatar/memento/Star.java
View File

@ -24,9 +24,7 @@
package com.iluwatar.memento;
/**
*
* Star uses "mementos" to store and restore state.
*
*/
public class Star {
@ -35,7 +33,7 @@ public class Star {
private int massTons;
/**
* Constructor
* Constructor.
*/
public Star(StarType startType, int startAge, int startMass) {
this.type = startType;
@ -44,7 +42,7 @@ public class Star {
}
/**
* Makes time pass for the star
* Makes time pass for the star.
*/
public void timePasses() {
ageYears *= 2;
@ -96,9 +94,7 @@ public class Star {
}
/**
*
* StarMemento implementation
*
* StarMemento implementation.
*/
private static class StarMementoInternal implements StarMemento {

2
memento/src/main/java/com/iluwatar/memento/StarMemento.java
View File

@ -24,9 +24,7 @@
package com.iluwatar.memento;
/**
*
* External interface to memento.
*
*/
public interface StarMemento {

4
memento/src/main/java/com/iluwatar/memento/StarType.java
View File

@ -24,9 +24,7 @@
package com.iluwatar.memento;
/**
*
* StarType enumeration
*
* StarType enumeration.
*/
public enum StarType {

26
model-view-controller/src/main/java/com/iluwatar/model/view/controller/App.java
View File

@ -24,27 +24,25 @@
package com.iluwatar.model.view.controller;
/**
*
* Model-View-Controller is a pattern for implementing user interfaces. It divides the application
* into three interconnected parts namely the model, the view and the controller.
* <p>
* The central component of MVC, the model, captures the behavior of the application in terms of its
* problem domain, independent of the user interface. The model directly manages the data, logic and
* rules of the application. A view can be any output representation of information, such as a chart
* or a diagram The third part, the controller, accepts input and converts it to commands for the
* model or view.
* <p>
* In this example we have a giant ({@link GiantModel}) with statuses for health, fatigue and
* nourishment. {@link GiantView} can display the giant with its current status.
* {@link GiantController} receives input affecting the model and delegates redrawing the giant to
* the view.
*
* <p>The central component of MVC, the model, captures the behavior of the application in terms of
* its problem domain, independent of the user interface. The model directly manages the data, logic
* and rules of the application. A view can be any output representation of information, such as a
* chart or a diagram The third part, the controller, accepts input and converts it to commands for
* the model or view.
*
* <p>In this example we have a giant ({@link GiantModel}) with statuses for health, fatigue and
* nourishment. {@link GiantView} can display the giant with its current status. {@link
* GiantController} receives input affecting the model and delegates redrawing the giant to the
* view.
*/
public class App {
/**
* Program entry point
*
* Program entry point.
*
* @param args command line args
*/
public static void main(String[] args) {

4
model-view-controller/src/main/java/com/iluwatar/model/view/controller/Fatigue.java
View File

@ -24,9 +24,7 @@
package com.iluwatar.model.view.controller;
/**
*
* Fatigue enumeration
*
* Fatigue enumeration.
*/
public enum Fatigue {

2
model-view-controller/src/main/java/com/iluwatar/model/view/controller/GiantController.java
View File

@ -24,9 +24,7 @@
package com.iluwatar.model.view.controller;
/**
*
* GiantController can update the giant data and redraw it using the view.
*
*/
public class GiantController {

4
model-view-controller/src/main/java/com/iluwatar/model/view/controller/GiantModel.java
View File

@ -24,9 +24,7 @@
package com.iluwatar.model.view.controller;
/**
*
* GiantModel contains the giant data
*
* GiantModel contains the giant data.
*/
public class GiantModel {

4
model-view-controller/src/main/java/com/iluwatar/model/view/controller/GiantView.java
View File

@ -27,9 +27,7 @@ import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
*
* GiantView displays the giant
*
* GiantView displays the giant.
*/
public class GiantView {

4
model-view-controller/src/main/java/com/iluwatar/model/view/controller/Health.java
View File

@ -24,9 +24,7 @@
package com.iluwatar.model.view.controller;
/**
*
* Health enumeration
*
* Health enumeration.
*/
public enum Health {

4
model-view-controller/src/main/java/com/iluwatar/model/view/controller/Nourishment.java
View File

@ -24,9 +24,7 @@
package com.iluwatar.model.view.controller;
/**
*
* Nourishment enumeration
*
* Nourishment enumeration.
*/
public enum Nourishment {

32
model-view-presenter/src/main/java/com/iluwatar/model/view/presenter/App.java
View File

@ -24,31 +24,29 @@
package com.iluwatar.model.view.presenter;
/**
*
* The Model-View-Presenter(MVP) architectural pattern, helps us achieve what is called
* "The separation of concerns" principle. This is accomplished by separating the application's
* logic (Model), GUIs (View), and finally the way that the user's actions update the application's
* logic (Presenter).
* <p>
* In the following example, The {@link FileLoader} class represents the app's logic, the
* {@link FileSelectorJFrame} is the GUI and the {@link FileSelectorPresenter} is responsible to
* respond to users' actions.
* <p>
* Finally, please notice the wiring between the Presenter and the View and between the Presenter
* and the Model.
*
* The Model-View-Presenter(MVP) architectural pattern, helps us achieve what is called "The
* separation of concerns" principle. This is accomplished by separating the application's logic
* (Model), GUIs (View), and finally the way that the user's actions update the application's logic
* (Presenter).
*
* <p>In the following example, The {@link FileLoader} class represents the app's logic, the {@link
* FileSelectorJFrame} is the GUI and the {@link FileSelectorPresenter} is responsible to respond to
* users' actions.
*
* <p>Finally, please notice the wiring between the Presenter and the View and between the
* Presenter and the Model.
*/
public class App {
/**
* Program entry point
*
* Program entry point.
*
* @param args command line args
*/
public static void main(String[] args) {
FileLoader loader = new FileLoader();
FileSelectorJFrame jFrame = new FileSelectorJFrame();
FileSelectorPresenter presenter = new FileSelectorPresenter(jFrame);
FileSelectorJFrame frame = new FileSelectorJFrame();
FileSelectorPresenter presenter = new FileSelectorPresenter(frame);
presenter.setLoader(loader);
presenter.start();
}

17
model-view-presenter/src/main/java/com/iluwatar/model/view/presenter/FileLoader.java
View File

@ -27,23 +27,22 @@ import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.io.Serializable;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* Every instance of this class represents the Model component in the Model-View-Presenter
* architectural pattern.
* <p>
* It is responsible for reading and loading the contents of a given file.
*
* <p>It is responsible for reading and loading the contents of a given file.
*/
public class FileLoader implements Serializable {
/**
* Generated serial version UID
* Generated serial version UID.
*/
private static final long serialVersionUID = -4745803872902019069L;
private static final Logger LOGGER = LoggerFactory.getLogger(FileLoader.class);
/**
@ -81,7 +80,7 @@ public class FileLoader implements Serializable {
/**
* Sets the path of the file to be loaded, to the given value.
*
*
* @param fileName The path of the file to be loaded.
*/
public void setFileName(String fileName) {
@ -89,6 +88,8 @@ public class FileLoader implements Serializable {
}
/**
* Gets the path of the file to be loaded.
*
* @return fileName The path of the file to be loaded.
*/
public String getFileName() {
@ -96,6 +97,8 @@ public class FileLoader implements Serializable {
}
/**
* Returns true if the given file exists.
*
* @return True, if the file given exists, false otherwise.
*/
public boolean fileExists() {
@ -103,6 +106,8 @@ public class FileLoader implements Serializable {
}
/**
* Returns true if the given file is loaded.
*
* @return True, if the file is loaded, false otherwise.
*/
public boolean isLoaded() {

3
model-view-presenter/src/main/java/com/iluwatar/model/view/presenter/FileSelectorJFrame.java
View File

@ -26,7 +26,6 @@ package com.iluwatar.model.view.presenter;
import java.awt.Color;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
@ -82,7 +81,7 @@ public class FileSelectorJFrame extends JFrame implements FileSelectorView, Acti
private JPanel panel;
/**
* The Presenter component that the frame will interact with
* The Presenter component that the frame will interact with.
*/
private FileSelectorPresenter presenter;

14
model-view-presenter/src/main/java/com/iluwatar/model/view/presenter/FileSelectorPresenter.java
View File

@ -28,13 +28,13 @@ import java.io.Serializable;
/**
* Every instance of this class represents the Presenter component in the Model-View-Presenter
* architectural pattern.
* <p>
* It is responsible for reacting to the user's actions and update the View component.
*
* <p>It is responsible for reacting to the user's actions and update the View component.
*/
public class FileSelectorPresenter implements Serializable {
/**
* Generated serial version UID
* Generated serial version UID.
*/
private static final long serialVersionUID = 1210314339075855074L;
@ -49,8 +49,8 @@ public class FileSelectorPresenter implements Serializable {
private FileLoader loader;
/**
* Constructor
*
* Constructor.
*
* @param view The view component that the presenter will interact with.
*/
public FileSelectorPresenter(FileSelectorView view) {
@ -59,7 +59,7 @@ public class FileSelectorPresenter implements Serializable {
/**
* Sets the {@link FileLoader} object, to the value given as parameter.
*
*
* @param loader The new {@link FileLoader} object(the Model component).
*/
public void setLoader(FileLoader loader) {
@ -82,7 +82,7 @@ public class FileSelectorPresenter implements Serializable {
}
/**
* Ok button handler
* Ok button handler.
*/
public void confirmed() {
if (loader.getFileName() == null || loader.getFileName().equals("")) {

14
model-view-presenter/src/main/java/com/iluwatar/model/view/presenter/FileSelectorStub.java
View File

@ -26,12 +26,12 @@ package com.iluwatar.model.view.presenter;
/**
* Every instance of this class represents the Stub component in the Model-View-Presenter
* architectural pattern.
* <p>
* The stub implements the View interface and it is useful when we want the test the reaction to
*
* <p>The stub implements the View interface and it is useful when we want the test the reaction to
* user events, such as mouse clicks.
* <p>
* Since we can not test the GUI directly, the MVP pattern provides this functionality through the
* View's dummy implementation, the Stub.
*
* <p>Since we can not test the GUI directly, the MVP pattern provides this functionality through
* the View's dummy implementation, the Stub.
*/
public class FileSelectorStub implements FileSelectorView {
@ -61,7 +61,7 @@ public class FileSelectorStub implements FileSelectorView {
private boolean dataDisplayed;
/**
* Constructor
* Constructor.
*/
public FileSelectorStub() {
this.opened = false;
@ -124,6 +124,8 @@ public class FileSelectorStub implements FileSelectorView {
}
/**
* Returns true, if the data were displayed.
*
* @return True if the data where displayed, false otherwise.
*/
public boolean dataDisplayed() {

14
model-view-presenter/src/main/java/com/iluwatar/model/view/presenter/FileSelectorView.java
View File

@ -42,44 +42,50 @@ public interface FileSelectorView extends Serializable {
void close();
/**
* Returns true if view is opened.
*
* @return True, if the view is opened, false otherwise.
*/
boolean isOpened();
/**
* Sets the presenter component, to the one given as parameter.
*
*
* @param presenter The new presenter component.
*/
void setPresenter(FileSelectorPresenter presenter);
/**
* Gets presenter component.
*
* @return The presenter Component.
*/
FileSelectorPresenter getPresenter();
/**
* Sets the file's name, to the value given as parameter.
*
*
* @param name The new name of the file.
*/
void setFileName(String name);
/**
* Gets the name of file.
*
* @return The name of the file.
*/
String getFileName();
/**
* Displays a message to the users.
*
*
* @param message The message to be displayed.
*/
void showMessage(String message);
/**
* Displays the data to the view.
*
*
* @param data The data to be written.
*/
void displayData(String data);

21
module/src/main/java/com/iluwatar/module/App.java
View File

@ -31,10 +31,9 @@ import java.io.FileNotFoundException;
* An object that applies this pattern can provide the equivalent of a namespace, providing the
* initialization and finalization process of a static class or a class with static members with
* cleaner, more concise syntax and semantics.
* <p>
* The below example demonstrates a use case for testing two different modules: File Logger and
*
* <p>The below example demonstrates a use case for testing two different modules: File Logger and
* Console Logger
*
*/
public class App {
@ -42,10 +41,10 @@ public class App {
public static ConsoleLoggerModule consoleLoggerModule;
/**
* Following method performs the initialization
*
* Following method performs the initialization.
*
* @throws FileNotFoundException if program is not able to find log files (output.txt and
* error.txt)
* error.txt)
*/
public static void prepare() throws FileNotFoundException {
@ -55,7 +54,7 @@ public class App {
}
/**
* Following method performs the finalization
* Following method performs the finalization.
*/
public static void unprepare() {
@ -65,8 +64,8 @@ public class App {
}
/**
* Following method is main executor
*
* Following method is main executor.
*
* @param args for providing default program arguments
*/
public static void execute(final String... args) {
@ -82,10 +81,10 @@ public class App {
/**
* Program entry point.
*
*
* @param args command line args.
* @throws FileNotFoundException if program is not able to find log files (output.txt and
* error.txt)
* error.txt)
*/
public static void main(final String... args) throws FileNotFoundException {
prepare();

30
module/src/main/java/com/iluwatar/module/ConsoleLoggerModule.java
View File

@ -23,16 +23,15 @@
package com.iluwatar.module;
import java.io.PrintStream;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.io.PrintStream;
/**
* The ConsoleLoggerModule is responsible for showing logs on System Console
* <p>
* The below example demonstrates a Console logger module, which can print simple and error messages
* in two designated formats
* The ConsoleLoggerModule is responsible for showing logs on System Console.
*
* <p>The below example demonstrates a Console logger module, which can print simple and error
* messages in two designated formats
*/
public final class ConsoleLoggerModule {
@ -43,11 +42,12 @@ public final class ConsoleLoggerModule {
public PrintStream output = null;
public PrintStream error = null;
private ConsoleLoggerModule() {}
private ConsoleLoggerModule() {
}
/**
* Static method to get single instance of class
*
* Static method to get single instance of class.
*
* @return singleton instance of ConsoleLoggerModule
*/
public static ConsoleLoggerModule getSingleton() {
@ -60,7 +60,7 @@ public final class ConsoleLoggerModule {
}
/**
* Following method performs the initialization
* Following method performs the initialization.
*/
public ConsoleLoggerModule prepare() {
@ -73,7 +73,7 @@ public final class ConsoleLoggerModule {
}
/**
* Following method performs the finalization
* Following method performs the finalization.
*/
public void unprepare() {
@ -93,8 +93,8 @@ public final class ConsoleLoggerModule {
}
/**
* Used to print a message
*
* Used to print a message.
*
* @param value will be printed on console
*/
public void printString(final String value) {
@ -102,8 +102,8 @@ public final class ConsoleLoggerModule {
}
/**
* Used to print a error message
*
* Used to print a error message.
*
* @param value will be printed on error console
*/
public void printErrorString(final String value) {

36
module/src/main/java/com/iluwatar/module/FileLoggerModule.java
View File

@ -23,18 +23,17 @@
package com.iluwatar.module;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.PrintStream;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* The FileLoggerModule is responsible for showing logs on File System
* <p>
* The below example demonstrates a File logger module, which can print simple and error messages in
* two designated files
* The FileLoggerModule is responsible for showing logs on File System.
*
* <p>The below example demonstrates a File logger module, which can print simple and error
* messages in two designated files
*/
public final class FileLoggerModule {
@ -48,11 +47,12 @@ public final class FileLoggerModule {
public PrintStream output = null;
public PrintStream error = null;
private FileLoggerModule() {}
private FileLoggerModule() {
}
/**
* Static method to get single instance of class
*
* Static method to get single instance of class.
*
* @return singleton instance of FileLoggerModule
*/
public static FileLoggerModule getSingleton() {
@ -65,10 +65,10 @@ public final class FileLoggerModule {
}
/**
* Following method performs the initialization
*
* Following method performs the initialization.
*
* @throws FileNotFoundException if program is not able to find log files (output.txt and
* error.txt)
* error.txt)
*/
public FileLoggerModule prepare() throws FileNotFoundException {
@ -81,7 +81,7 @@ public final class FileLoggerModule {
}
/**
* Following method performs the finalization
* Following method performs the finalization.
*/
public void unprepare() {
@ -101,8 +101,8 @@ public final class FileLoggerModule {
}
/**
* Used to print a message
*
* Used to print a message.
*
* @param value will be printed in file
*/
public void printString(final String value) {
@ -110,8 +110,8 @@ public final class FileLoggerModule {
}
/**
* Used to print a error message
*
* Used to print a error message.
*
* @param value will be printed on error file
*/
public void printErrorString(final String value) {

28
monad/src/main/java/com/iluwatar/monad/App.java
View File

@ -23,26 +23,27 @@
package com.iluwatar.monad;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.util.Objects;
import java.util.function.Function;
import java.util.function.Predicate;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* The Monad pattern defines a monad structure, that enables chaining operations
* in pipelines and processing data step by step.
* Formally, monad consists of a type constructor M and two operations:
* The Monad pattern defines a monad structure, that enables chaining operations in pipelines and
* processing data step by step. Formally, monad consists of a type constructor M and two
* operations:
* <br>bind - that takes monadic object and a function from plain object to the
* monadic value and returns monadic value.
* <br>return - that takes plain type object and returns this object wrapped in a monadic value.
* <p>
* In the given example, the Monad pattern is represented as a {@link Validator} that takes an instance
* of a plain object with {@link Validator#of(Object)}
* and validates it {@link Validator#validate(Function, Predicate, String)} against given predicates.
* <p>As a validation result {@link Validator#get()} it either returns valid object {@link Validator#t}
* or throws a list of exceptions {@link Validator#exceptions} collected during validation.
*
* <p>In the given example, the Monad pattern is represented as a {@link Validator} that takes an
* instance of a plain object with {@link Validator#of(Object)} and validates it {@link
* Validator#validate(Function, Predicate, String)} against given predicates.
*
* <p>As a validation result {@link Validator#get()} it either returns valid object {@link
* Validator#t} or throws a list of exceptions {@link Validator#exceptions} collected during
* validation.
*/
public class App {
@ -58,6 +59,7 @@ public class App {
LOGGER.info(Validator.of(user).validate(User::getName, Objects::nonNull, "name is null")
.validate(User::getName, name -> !name.isEmpty(), "name is empty")
.validate(User::getEmail, email -> !email.contains("@"), "email doesn't containt '@'")
.validate(User::getAge, age -> age > 20 && age < 30, "age isn't between...").get().toString());
.validate(User::getAge, age -> age > 20 && age < 30, "age isn't between...").get()
.toString());
}
}

2
monad/src/main/java/com/iluwatar/monad/Sex.java
View File

@ -24,7 +24,7 @@
package com.iluwatar.monad;
/**
* Enumeration of Types of Sex
* Enumeration of Types of Sex.
*/
public enum Sex {
MALE, FEMALE

4
monad/src/main/java/com/iluwatar/monad/User.java
View File

@ -24,7 +24,7 @@
package com.iluwatar.monad;
/**
* User Definition
* User Definition.
*/
public class User {
@ -34,6 +34,8 @@ public class User {
private String email;
/**
* Constructor.
*
* @param name - name
* @param age - age
* @param sex - sex

41
monad/src/main/java/com/iluwatar/monad/Validator.java
View File

@ -30,18 +30,18 @@ import java.util.function.Function;
import java.util.function.Predicate;
/**
* Class representing Monad design pattern. Monad is a way of chaining operations on the
* given object together step by step. In Validator each step results in either success or
* failure indicator, giving a way of receiving each of them easily and finally getting
* validated object or list of exceptions.
* Class representing Monad design pattern. Monad is a way of chaining operations on the given
* object together step by step. In Validator each step results in either success or failure
* indicator, giving a way of receiving each of them easily and finally getting validated object or
* list of exceptions.
*
* @param <T> Placeholder for an object.
*/
public class Validator<T> {
/**
* Object that is validated
* Object that is validated.
*/
private final T t;
private final T obj;
/**
* List of exception thrown during validation.
@ -50,14 +50,15 @@ public class Validator<T> {
/**
* Creates a monadic value of given object.
* @param t object to be validated
*
* @param obj object to be validated
*/
private Validator(T t) {
this.t = t;
private Validator(T obj) {
this.obj = obj;
}
/**
* Creates validator against given object
* Creates validator against given object.
*
* @param t object to be validated
* @param <T> object's type
@ -68,25 +69,27 @@ public class Validator<T> {
}
/**
* @param validation one argument boolean-valued function that
* represents one step of validation. Adds exception to main validation exception
* list when single step validation ends with failure.
* Checks if the validation is successful.
*
* @param validation one argument boolean-valued function that represents one step of validation.
* Adds exception to main validation exception list when single step validation
* ends with failure.
* @param message error message when object is invalid
* @return this
*/
public Validator<T> validate(Predicate<T> validation, String message) {
if (!validation.test(t)) {
if (!validation.test(obj)) {
exceptions.add(new IllegalStateException(message));
}
return this;
}
/**
* Extension for the {@link Validator#validate(Function, Predicate, String)} method,
* dedicated for objects, that need to be projected before requested validation.
* Extension for the {@link Validator#validate(Function, Predicate, String)} method, dedicated for
* objects, that need to be projected before requested validation.
*
* @param projection function that gets an objects, and returns projection representing
* element to be validated.
* @param projection function that gets an objects, and returns projection representing element to
* be validated.
* @param validation see {@link Validator#validate(Function, Predicate, String)}
* @param message see {@link Validator#validate(Function, Predicate, String)}
* @param <U> see {@link Validator#validate(Function, Predicate, String)}
@ -105,7 +108,7 @@ public class Validator<T> {
*/
public T get() throws IllegalStateException {
if (exceptions.isEmpty()) {
return t;
return obj;
}
IllegalStateException e = new IllegalStateException();
exceptions.forEach(e::addSuppressed);

16
monostate/src/main/java/com/iluwatar/monostate/App.java
View File

@ -24,28 +24,22 @@
package com.iluwatar.monostate;
/**
*
* The MonoState pattern ensures that all instances of the class will have the same state. This can
* be used a direct replacement of the Singleton pattern.
*
* <p>
* In the following example, The {@link LoadBalancer} class represents the app's logic. It contains
* a series of Servers, which can handle requests of type {@link Request}. Two instances of
*
* <p>In the following example, The {@link LoadBalancer} class represents the app's logic. It
* contains a series of Servers, which can handle requests of type {@link Request}. Two instances of
* LoadBalacer are created. When a request is made to a server via the first LoadBalancer the state
* change in the first load balancer affects the second. So if the first LoadBalancer selects the
* Server 1, the second LoadBalancer on a new request will select the Second server. If a third
* LoadBalancer is created and a new request is made to it, then it will select the third server as
* the second load balancer has already selected the second server.
* <p>
* .
*
*/
public class App {
/**
* Program entry point
*
* Program entry point.
*
* @param args command line args
*/
public static void main(String[] args) {

9
monostate/src/main/java/com/iluwatar/monostate/LoadBalancer.java
View File

@ -31,7 +31,6 @@ import java.util.List;
* receiving a new Request, it delegates the call to the servers in a Round Robin Fashion. Since all
* instances of the class share the same state, all instances will delegate to the same server on
* receiving a new Request.
*
*/
public class LoadBalancer {
@ -40,13 +39,13 @@ public class LoadBalancer {
static {
int id = 0;
for (int port : new int[] {8080, 8081, 8082, 8083, 8084}) {
for (int port : new int[]{8080, 8081, 8082, 8083, 8084}) {
SERVERS.add(new Server("localhost", port, ++id));
}
}
/**
* Add new server
* Add new server.
*/
public final void addServer(Server server) {
synchronized (SERVERS) {
@ -64,7 +63,7 @@ public class LoadBalancer {
}
/**
* Handle request
* Handle request.
*/
public synchronized void serverRequest(Request request) {
if (lastServedId >= SERVERS.size()) {
@ -73,5 +72,5 @@ public class LoadBalancer {
Server server = SERVERS.get(lastServedId++);
server.serve(request);
}
}

2
monostate/src/main/java/com/iluwatar/monostate/Request.java
View File

@ -24,9 +24,7 @@
package com.iluwatar.monostate;
/**
*
* The Request class. A {@link Server} can handle an instance of a Request.
*
*/
public class Request {

6
monostate/src/main/java/com/iluwatar/monostate/Server.java
View File

@ -27,10 +27,8 @@ import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
*
* The Server class. Each Server sits behind a LoadBalancer which delegates the call to the servers
* in a simplistic Round Robin fashion.
*
*/
public class Server {
@ -41,7 +39,7 @@ public class Server {
public final int id;
/**
* Constructor
* Constructor.
*/
public Server(String host, int port, int id) {
this.host = host;
@ -59,6 +57,6 @@ public class Server {
public void serve(Request request) {
LOGGER.info("Server ID {} associated to host : {} and port {}. Processed request with value {}",
id, host, port, request.value);
id, host, port, request.value);
}
}

20
multiton/src/main/java/com/iluwatar/multiton/App.java
View File

@ -27,26 +27,24 @@ import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
*
* Whereas Singleton design pattern introduces single globally accessible object the Multiton
* pattern defines many globally accessible objects. The client asks for the correct instance from
* the Multiton by passing an enumeration as parameter.
* <p>
* There is more than one way to implement the multiton design pattern. In the first example
* {@link Nazgul} is the Multiton and we can ask single {@link Nazgul} from it using {@link NazgulName}.
* The {@link Nazgul}s are statically initialized and stored in concurrent hash map.
* <p>
* In the enum implementation {@link NazgulEnum} is the multiton. It is static and mutable because
* of the way java supports enums.
*
* <p>There is more than one way to implement the multiton design pattern. In the first example
* {@link Nazgul} is the Multiton and we can ask single {@link Nazgul} from it using {@link
* NazgulName}. The {@link Nazgul}s are statically initialized and stored in concurrent hash map.
*
* <p>In the enum implementation {@link NazgulEnum} is the multiton. It is static and mutable
* because of the way java supports enums.
*/
public class App {
private static final Logger LOGGER = LoggerFactory.getLogger(App.class);
/**
* Program entry point
*
* Program entry point.
*
* @param args command line args
*/
public static void main(String[] args) {
@ -60,7 +58,7 @@ public class App {
LOGGER.info("ADUNAPHEL={}", Nazgul.getInstance(NazgulName.ADUNAPHEL));
LOGGER.info("REN={}", Nazgul.getInstance(NazgulName.REN));
LOGGER.info("UVATHA={}", Nazgul.getInstance(NazgulName.UVATHA));
// enum multiton
LOGGER.info("KHAMUL={}", NazgulEnum.KHAMUL);
LOGGER.info("MURAZOR={}", NazgulEnum.MURAZOR);

2
multiton/src/main/java/com/iluwatar/multiton/Nazgul.java
View File

@ -27,9 +27,7 @@ import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
/**
*
* Nazgul is a Multiton class. Nazgul instances can be queried using {@link #getInstance} method.
*
*/
public final class Nazgul {

5
multiton/src/main/java/com/iluwatar/multiton/NazgulEnum.java
View File

@ -24,11 +24,10 @@
package com.iluwatar.multiton;
/**
* enum based multiton implementation
*
* enum based multiton implementation.
*/
public enum NazgulEnum {
KHAMUL, MURAZOR, DWAR, JI_INDUR, AKHORAHIL, HOARMURATH, ADUNAPHEL, REN, UVATHA;
}

2
multiton/src/main/java/com/iluwatar/multiton/NazgulName.java
View File

@ -24,9 +24,7 @@
package com.iluwatar.multiton;
/**
*
* Each Nazgul has different {@link NazgulName}.
*
*/
public enum NazgulName {

21
mute-idiom/src/main/java/com/iluwatar/mute/App.java
View File

@ -23,19 +23,17 @@
package com.iluwatar.mute;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.sql.SQLException;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* Mute pattern is utilized when we need to suppress an exception due to an API flaw or in
* situation when all we can do to handle the exception is to log it.
* This pattern should not be used everywhere. It is very important to logically handle the
* exceptions in a system, but some situations like the ones described above require this pattern,
* so that we don't need to repeat
* Mute pattern is utilized when we need to suppress an exception due to an API flaw or in situation
* when all we can do to handle the exception is to log it. This pattern should not be used
* everywhere. It is very important to logically handle the exceptions in a system, but some
* situations like the ones described above require this pattern, so that we don't need to repeat
* <pre>
* <code>
* try {
@ -45,7 +43,6 @@ import java.sql.SQLException;
* }
* </code>
* </pre> every time we need to ignore an exception.
*
*/
public class App {
@ -53,7 +50,7 @@ public class App {
/**
* Program entry point.
*
*
* @param args command line args.
* @throws Exception if any exception occurs
*/
@ -65,7 +62,7 @@ public class App {
}
/*
* Typically used when the API declares some exception but cannot do so. Usually a
* Typically used when the API declares some exception but cannot do so. Usually a
* signature mistake.In this example out is not supposed to throw exception as it is a
* ByteArrayOutputStream. So we utilize mute, which will throw AssertionError if unexpected
* exception occurs.
@ -98,7 +95,7 @@ public class App {
private static Resource acquireResource() throws SQLException {
return new Resource() {
@Override
public void close() throws IOException {
throw new IOException("Error in closing resource: " + this);

2
mute-idiom/src/main/java/com/iluwatar/mute/CheckedRunnable.java
View File

@ -25,12 +25,12 @@ package com.iluwatar.mute;
/**
* A runnable which may throw exception on execution.
*
*/
@FunctionalInterface
public interface CheckedRunnable {
/**
* Same as {@link Runnable#run()} with a possibility of exception in execution.
*
* @throws Exception if any exception occurs.
*/
void run() throws Exception;

27
mute-idiom/src/main/java/com/iluwatar/mute/Mute.java
View File

@ -30,17 +30,18 @@ import java.io.IOException;
* A utility class that allows you to utilize mute idiom.
*/
public final class Mute {
// The constructor is never meant to be called.
private Mute() {}
private Mute() {
}
/**
* Executes the <code>runnable</code> and throws the exception occurred within a {@link AssertionError}.
* This method should be utilized to mute the operations that are guaranteed not to throw an exception.
* For instance {@link ByteArrayOutputStream#write(byte[])} declares in it's signature that it can throw
* an {@link IOException}, but in reality it cannot. This is because the bulk write method is not overridden
* in {@link ByteArrayOutputStream}.
*
* Executes the <code>runnable</code> and throws the exception occurred within a {@link
* AssertionError}. This method should be utilized to mute the operations that are guaranteed not
* to throw an exception. For instance {@link ByteArrayOutputStream#write(byte[])} declares in
* it's signature that it can throw an {@link IOException}, but in reality it cannot. This is
* because the bulk write method is not overridden in {@link ByteArrayOutputStream}.
*
* @param runnable a runnable that should never throw an exception on execution.
*/
public static void mute(CheckedRunnable runnable) {
@ -52,11 +53,11 @@ public final class Mute {
}
/**
* Executes the <code>runnable</code> and logs the exception occurred on {@link System#err}.
* This method should be utilized to mute the operations about which most you can do is log.
* For instance while closing a connection to database, or cleaning up a resource,
* all you can do is log the exception occurred.
*
* Executes the <code>runnable</code> and logs the exception occurred on {@link System#err}. This
* method should be utilized to mute the operations about which most you can do is log. For
* instance while closing a connection to database, or cleaning up a resource, all you can do is
* log the exception occurred.
*
* @param runnable a runnable that may throw an exception on execution.
*/
public static void loggedMute(CheckedRunnable runnable) {

5
mute-idiom/src/main/java/com/iluwatar/mute/Resource.java
View File

@ -26,9 +26,8 @@ package com.iluwatar.mute;
import java.io.Closeable;
/**
* Represents any resource that the application might acquire and that must be closed
* after it is utilized. Example of such resources can be a database connection, open
* files, sockets.
* Represents any resource that the application might acquire and that must be closed after it is
* utilized. Example of such resources can be a database connection, open files, sockets.
*/
public interface Resource extends Closeable {

16
mutex/src/main/java/com/iluwatar/mutex/App.java
View File

@ -25,19 +25,17 @@ package com.iluwatar.mutex;
/**
* A Mutex prevents multiple threads from accessing a resource simultaneously.
* <p>
* In this example we have two thieves who are taking beans from a jar.
* Only one thief can take a bean at a time. This is ensured by a Mutex lock
* which must be acquired in order to access the jar. Each thief attempts to
* acquire the lock, take a bean and then release the lock. If the lock has
* already been acquired, the thief will be prevented from continuing (blocked)
* until the lock has been released. The thieves stop taking beans once there
* are no beans left to take.
*
* <p>In this example we have two thieves who are taking beans from a jar. Only one thief can take
* a bean at a time. This is ensured by a Mutex lock which must be acquired in order to access the
* jar. Each thief attempts to acquire the lock, take a bean and then release the lock. If the lock
* has already been acquired, the thief will be prevented from continuing (blocked) until the lock
* has been released. The thieves stop taking beans once there are no beans left to take.
*/
public class App {
/**
* main method
* main method.
*/
public static void main(String[] args) {
Mutex mutex = new Mutex();

5
mutex/src/main/java/com/iluwatar/mutex/Jar.java
View File

@ -24,9 +24,8 @@
package com.iluwatar.mutex;
/**
* A Jar has a resource of beans which can only be accessed by a single Thief
* (thread) at any one time. A Mutex lock is used to prevent more than one Thief
* taking a bean simultaneously.
* A Jar has a resource of beans which can only be accessed by a single Thief (thread) at any one
* time. A Mutex lock is used to prevent more than one Thief taking a bean simultaneously.
*/
public class Jar {

9
mutex/src/main/java/com/iluwatar/mutex/Mutex.java
View File

@ -34,16 +34,15 @@ public class Mutex implements Lock {
private Object owner;
/**
* Returns the current owner of the Mutex, or null if available
* Returns the current owner of the Mutex, or null if available.
*/
public Object getOwner() {
return owner;
}
/**
* Method called by a thread to acquire the lock. If the lock has already
* been acquired this will wait until the lock has been released to
* re-attempt the acquire.
* Method called by a thread to acquire the lock. If the lock has already been acquired this will
* wait until the lock has been released to re-attempt the acquire.
*/
@Override
public synchronized void acquire() throws InterruptedException {

13
mutex/src/main/java/com/iluwatar/mutex/Thief.java
View File

@ -27,20 +27,20 @@ import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* Thief is a class which continually tries to acquire a jar and take a bean
* from it. When the jar is empty the thief stops.
* Thief is a class which continually tries to acquire a jar and take a bean from it. When the jar
* is empty the thief stops.
*/
public class Thief extends Thread {
private static final Logger LOGGER = LoggerFactory.getLogger(Thief.class);
/**
* The name of the thief.
* The name of the thief.
*/
private final String name;
/**
* The jar
* The jar.
*/
private final Jar jar;
@ -50,8 +50,7 @@ public class Thief extends Thread {
}
/**
* In the run method the thief repeatedly tries to take a bean until none
* are left.
* In the run method the thief repeatedly tries to take a bean until none are left.
*/
@Override
public void run() {