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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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45
master-worker-pattern/src/main/java/com/iluwatar/masterworker/App.java
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@@ -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
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@@ -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
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@@ -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
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@@ -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
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@@ -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
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@@ -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();