docs: update master-worker

master-worker/src/main/java/com/iluwatar/masterworker/App.java

@@ -0,0 +1,82 @@
+/*
+ * This project is licensed under the MIT license. Module model-view-viewmodel is using ZK framework licensed under LGPL (see lgpl-3.0.txt).
+ *
+ * The MIT License
+ * Copyright © 2014-2022 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+package com.iluwatar.masterworker;
+
+import com.iluwatar.masterworker.system.ArrayTransposeMasterWorker;
+import com.iluwatar.masterworker.system.MasterWorker;
+import com.iluwatar.masterworker.system.systemmaster.ArrayTransposeMaster;
+import com.iluwatar.masterworker.system.systemmaster.Master;
+import com.iluwatar.masterworker.system.systemworkers.ArrayTransposeWorker;
+import com.iluwatar.masterworker.system.systemworkers.Worker;
+import lombok.extern.slf4j.Slf4j;
+
+/**
+ * <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>
+ */
+
+@Slf4j
+public class App {
+
+  /**
+   * Program entry point.
+   *
+   * @param args command line args
+   */
+
+  public static void main(String[] args) {
+    var mw = new ArrayTransposeMasterWorker();
+    var rows = 10;
+    var columns = 20;
+    var inputMatrix = ArrayUtilityMethods.createRandomIntMatrix(rows, columns);
+    var input = new ArrayInput(inputMatrix);
+    var result = (ArrayResult) mw.getResult(input);
+    if (result != null) {
+      ArrayUtilityMethods.printMatrix(inputMatrix);
+      ArrayUtilityMethods.printMatrix(result.data);
+    } else {
+      LOGGER.info("Please enter non-zero input");
+    }
+  }
+
+}

master-worker/src/main/java/com/iluwatar/masterworker/ArrayInput.java

@@ -0,0 +1,85 @@
+/*
+ * This project is licensed under the MIT license. Module model-view-viewmodel is using ZK framework licensed under LGPL (see lgpl-3.0.txt).
+ *
+ * The MIT License
+ * Copyright © 2014-2022 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+package com.iluwatar.masterworker;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+
+/**
+ * Class ArrayInput extends abstract class {@link Input} and contains data of type int[][].
+ */
+
+public class ArrayInput extends Input<int[][]> {
+
+  public ArrayInput(int[][] data) {
+    super(data);
+  }
+
+  static int[] makeDivisions(int[][] data, int num) {
+    var initialDivision = data.length / num; //equally dividing
+    var divisions = new int[num];
+    Arrays.fill(divisions, initialDivision);
+    if (initialDivision * num != data.length) {
+      var extra = data.length - initialDivision * num;
+      var l = 0;
+      //equally dividing extra among all parts
+      while (extra > 0) {
+        divisions[l] = divisions[l] + 1;
+        extra--;
+        if (l == num - 1) {
+          l = 0;
+        } else {
+          l++;
+        }
+      }
+    }
+    return divisions;
+  }
+
+  @Override
+  public List<Input<int[][]>> divideData(int num) {
+    if (this.data == null) {
+      return null;
+    } else {
+      var divisions = makeDivisions(this.data, num);
+      var result = new ArrayList<Input<int[][]>>(num);
+      var rowsDone = 0; //number of rows divided so far
+      for (var i = 0; i < num; i++) {
+        var rows = divisions[i];
+        if (rows != 0) {
+          var divided = new int[rows][this.data[0].length];
+          System.arraycopy(this.data, rowsDone, divided, 0, rows);
+          rowsDone += rows;
+          var dividedInput = new ArrayInput(divided);
+          result.add(dividedInput);
+        } else {
+          break; //rest of divisions will also be 0
+        }
+      }
+      return result;
+    }
+  }
+}

master-worker/src/main/java/com/iluwatar/masterworker/ArrayResult.java

@@ -0,0 +1,36 @@
+/*
+ * This project is licensed under the MIT license. Module model-view-viewmodel is using ZK framework licensed under LGPL (see lgpl-3.0.txt).
+ *
+ * The MIT License
+ * Copyright © 2014-2022 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+package com.iluwatar.masterworker;
+
+/**
+ * Class ArrayResult extends abstract class {@link Result} and contains data of type int[][].
+ */
+
+public class ArrayResult extends Result<int[][]> {
+
+  public ArrayResult(int[][] data) {
+    super(data);
+  }
+}

master-worker/src/main/java/com/iluwatar/masterworker/ArrayUtilityMethods.java

@@ -0,0 +1,114 @@
+/*
+ * This project is licensed under the MIT license. Module model-view-viewmodel is using ZK framework licensed under LGPL (see lgpl-3.0.txt).
+ *
+ * The MIT License
+ * Copyright © 2014-2022 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+package com.iluwatar.masterworker;
+
+import java.security.SecureRandom;
+import lombok.extern.slf4j.Slf4j;
+
+/**
+ * Class ArrayUtilityMethods has some utility methods for matrices and arrays.
+ */
+
+@Slf4j
+public class ArrayUtilityMethods {
+
+  private static final SecureRandom RANDOM = new SecureRandom();
+
+  /**
+   * 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) {
+    //compares if 2 arrays have the same value
+    if (a1.length != a2.length) {
+      return false;
+    } else {
+      var answer = false;
+      for (var i = 0; i < a1.length; i++) {
+        if (a1[i] == a2[i]) {
+          answer = true;
+        } else {
+          answer = false;
+          break;
+        }
+      }
+      return answer;
+    }
+  }
+
+  /**
+   * 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;
+    } else {
+      var answer = false;
+      for (var i = 0; i < m1.length; i++) {
+        if (arraysSame(m1[i], m2[i])) {
+          answer = true;
+        } else {
+          answer = false;
+          break;
+        }
+      }
+      return answer;
+    }
+  }
+
+  /**
+   * Method createRandomIntMatrix creates a random matrix of size @param rows and @param columns.
+   *
+   * @return it (int[][]).
+   */
+  public static int[][] createRandomIntMatrix(int rows, int columns) {
+    var matrix = new int[rows][columns];
+    for (var i = 0; i < rows; i++) {
+      for (var j = 0; j < columns; j++) {
+        //filling cells in matrix
+        matrix[i][j] = RANDOM.nextInt(10);
+      }
+    }
+    return matrix;
+  }
+
+  /**
+   * Method printMatrix prints input matrix @param matrix.
+   */
+
+  public static void printMatrix(int[][] matrix) {
+    //prints out int[][]
+    for (var ints : matrix) {
+      for (var j = 0; j < matrix[0].length; j++) {
+        LOGGER.info(ints[j] + " ");
+      }
+      LOGGER.info("");
+    }
+  }
+
+}

master-worker/src/main/java/com/iluwatar/masterworker/Input.java

@@ -0,0 +1,45 @@
+/*
+ * This project is licensed under the MIT license. Module model-view-viewmodel is using ZK framework licensed under LGPL (see lgpl-3.0.txt).
+ *
+ * The MIT License
+ * Copyright © 2014-2022 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+package com.iluwatar.masterworker;
+
+import java.util.List;
+
+/**
+ * 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 List<Input<T>> divideData(int num);
+}

master-worker/src/main/java/com/iluwatar/masterworker/Result.java

@@ -0,0 +1,40 @@
+/*
+ * This project is licensed under the MIT license. Module model-view-viewmodel is using ZK framework licensed under LGPL (see lgpl-3.0.txt).
+ *
+ * The MIT License
+ * Copyright © 2014-2022 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+package com.iluwatar.masterworker;
+
+/**
+ * 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) {
+    this.data = data;
+  }
+}

master-worker/src/main/java/com/iluwatar/masterworker/system/ArrayTransposeMasterWorker.java

@@ -0,0 +1,45 @@
+/*
+ * This project is licensed under the MIT license. Module model-view-viewmodel is using ZK framework licensed under LGPL (see lgpl-3.0.txt).
+ *
+ * The MIT License
+ * Copyright © 2014-2022 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+package com.iluwatar.masterworker.system;
+
+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.
+ */
+
+public class ArrayTransposeMasterWorker extends MasterWorker {
+
+  public ArrayTransposeMasterWorker() {
+    super(4);
+  }
+
+  @Override
+  Master setMaster(int numOfWorkers) {
+    return new ArrayTransposeMaster(numOfWorkers);
+  }
+}

master-worker/src/main/java/com/iluwatar/masterworker/system/MasterWorker.java

@@ -0,0 +1,49 @@
+/*
+ * This project is licensed under the MIT license. Module model-view-viewmodel is using ZK framework licensed under LGPL (see lgpl-3.0.txt).
+ *
+ * The MIT License
+ * Copyright © 2014-2022 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+package com.iluwatar.masterworker.system;
+
+import com.iluwatar.masterworker.Input;
+import com.iluwatar.masterworker.Result;
+import com.iluwatar.masterworker.system.systemmaster.Master;
+
+/**
+ * The abstract MasterWorker class which contains reference to master.
+ */
+
+public abstract class MasterWorker {
+  private final Master master;
+
+  public MasterWorker(int numOfWorkers) {
+    this.master = setMaster(numOfWorkers);
+  }
+
+  abstract Master setMaster(int numOfWorkers);
+
+  public Result<?> getResult(Input<?> input) {
+    this.master.doWork(input);
+    return this.master.getFinalResult();
+  }
+}
+

master-worker/src/main/java/com/iluwatar/masterworker/system/systemmaster/ArrayTransposeMaster.java

@@ -0,0 +1,79 @@
+/*
+ * This project is licensed under the MIT license. Module model-view-viewmodel is using ZK framework licensed under LGPL (see lgpl-3.0.txt).
+ *
+ * The MIT License
+ * Copyright © 2014-2022 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+package com.iluwatar.masterworker.system.systemmaster;
+
+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.stream.Collectors;
+import java.util.stream.IntStream;
+
+/**
+ * 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 {
+  public ArrayTransposeMaster(int numOfWorkers) {
+    super(numOfWorkers);
+  }
+
+  @Override
+  ArrayList<Worker> setWorkers(int num) {
+    //i+1 will be id
+    return IntStream.range(0, num)
+        .mapToObj(i -> new ArrayTransposeWorker(this, i + 1))
+        .collect(Collectors.toCollection(() -> new ArrayList<>(num)));
+  }
+
+  @Override
+  ArrayResult aggregateData() {
+    // number of rows in final result is number of rows in any of obtained results from workers
+    var allResultData = this.getAllResultData();
+    var rows = ((ArrayResult) allResultData.elements().nextElement()).data.length;
+    var elements = allResultData.elements();
+    var columns = 0; // columns = sum of number of columns in all results obtained from workers
+    while (elements.hasMoreElements()) {
+      columns += ((ArrayResult) elements.nextElement()).data[0].length;
+    }
+    var resultData = new int[rows][columns];
+    var columnsDone = 0; //columns aggregated so far
+    var workers = this.getWorkers();
+    for (var i = 0; i < this.getExpectedNumResults(); i++) {
+      //result obtained from ith worker
+      var worker = workers.get(i);
+      var workerId = worker.getWorkerId();
+      var work = ((ArrayResult) allResultData.get(workerId)).data;
+      for (var m = 0; m < work.length; m++) {
+        //m = row number, n = columns number
+        System.arraycopy(work[m], 0, resultData[m], columnsDone, work[0].length);
+      }
+      columnsDone += work[0].length;
+    }
+    return new ArrayResult(resultData);
+  }
+
+}

master-worker/src/main/java/com/iluwatar/masterworker/system/systemmaster/Master.java

@@ -0,0 +1,108 @@
+/*
+ * This project is licensed under the MIT license. Module model-view-viewmodel is using ZK framework licensed under LGPL (see lgpl-3.0.txt).
+ *
+ * The MIT License
+ * Copyright © 2014-2022 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+package com.iluwatar.masterworker.system.systemmaster;
+
+import com.iluwatar.masterworker.Input;
+import com.iluwatar.masterworker.Result;
+import com.iluwatar.masterworker.system.systemworkers.Worker;
+import java.util.Hashtable;
+import java.util.List;
+import lombok.Getter;
+
+/**
+ * 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 {
+  private final int numOfWorkers;
+  private final List<Worker> workers;
+  private final Hashtable<Integer, Result<?>> allResultData;
+  private int expectedNumResults;
+  @Getter
+  private Result<?> finalResult;
+
+  Master(int numOfWorkers) {
+    this.numOfWorkers = numOfWorkers;
+    this.workers = setWorkers(numOfWorkers);
+    this.expectedNumResults = 0;
+    this.allResultData = new Hashtable<>(numOfWorkers);
+    this.finalResult = null;
+  }
+
+  Hashtable<Integer, Result<?>> getAllResultData() {
+    return this.allResultData;
+  }
+
+  int getExpectedNumResults() {
+    return this.expectedNumResults;
+  }
+
+  List<Worker> getWorkers() {
+    return this.workers;
+  }
+
+  abstract List<Worker> setWorkers(int num);
+
+  public void doWork(Input<?> input) {
+    divideWork(input);
+  }
+
+  private void divideWork(Input<?> input) {
+    var dividedInput = input.divideData(numOfWorkers);
+    if (dividedInput != null) {
+      this.expectedNumResults = dividedInput.size();
+      for (var 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).start();
+      }
+      for (var i = 0; i < this.expectedNumResults; i++) {
+        try {
+          this.workers.get(i).join();
+        } catch (InterruptedException e) {
+          System.err.println("Error while executing thread");
+        }
+      }
+    }
+  }
+
+  public void receiveData(Result<?> data, Worker w) {
+    // check if we 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) {
+      //all data received
+      this.finalResult = aggregateData();
+    }
+  }
+
+  abstract Result<?> aggregateData();
+}

master-worker/src/main/java/com/iluwatar/masterworker/system/systemworkers/ArrayTransposeWorker.java

@@ -0,0 +1,57 @@
+/*
+ * This project is licensed under the MIT license. Module model-view-viewmodel is using ZK framework licensed under LGPL (see lgpl-3.0.txt).
+ *
+ * The MIT License
+ * Copyright © 2014-2022 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+package com.iluwatar.masterworker.system.systemworkers;
+
+import com.iluwatar.masterworker.ArrayInput;
+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.
+ */
+
+public class ArrayTransposeWorker extends Worker {
+
+  public ArrayTransposeWorker(Master master, int id) {
+    super(master, id);
+  }
+
+  @Override
+  ArrayResult executeOperation() {
+    //number of rows in result matrix is equal to number of columns in input matrix and vice versa
+    var arrayInput = (ArrayInput) this.getReceivedData();
+    final var rows = arrayInput.data[0].length;
+    final var cols = arrayInput.data.length;
+    var resultData = new int[rows][cols];
+    for (var i = 0; i < cols; i++) {
+      for (var j = 0; j < rows; j++) {
+        //flipping element positions along diagonal
+        resultData[j][i] = arrayInput.data[i][j];
+      }
+    }
+    return new ArrayResult(resultData);
+  }
+}

master-worker/src/main/java/com/iluwatar/masterworker/system/systemworkers/Worker.java

@@ -0,0 +1,68 @@
+/*
+ * This project is licensed under the MIT license. Module model-view-viewmodel is using ZK framework licensed under LGPL (see lgpl-3.0.txt).
+ *
+ * The MIT License
+ * Copyright © 2014-2022 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+package com.iluwatar.masterworker.system.systemworkers;
+
+import com.iluwatar.masterworker.Input;
+import com.iluwatar.masterworker.Result;
+import com.iluwatar.masterworker.system.systemmaster.Master;
+import lombok.Getter;
+
+/**
+ * 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 {
+  private final Master master;
+  @Getter
+  private final int workerId;
+  private Input<?> receivedData;
+
+  Worker(Master master, int id) {
+    this.master = master;
+    this.workerId = id;
+    this.receivedData = null;
+  }
+
+  Input<?> getReceivedData() {
+    return this.receivedData;
+  }
+
+  public void setReceivedData(Master m, Input<?> i) {
+    // check if we are ready to receive... if yes:
+    this.receivedData = i;
+  }
+
+  abstract Result<?> executeOperation();
+
+  private void sendToMaster(Result<?> data) {
+    this.master.receiveData(data, this);
+  }
+
+  public void run() { //from Thread class
+    var work = executeOperation();
+    sendToMaster(work);
+  }
+}