8000 Objects, immutability and switch expressions · yogiprogram/Java-Coding-Problems@b9dd146 · GitHub
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AnghelLeonardAnghelLeonard
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Objects, immutability and switch expressions
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‎Chapter02/P53_CloningObjects/src/main/java/modern/challenge/Main.java

Lines changed: 51 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -7,14 +7,16 @@
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import java.io.IOException;
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import java.io.ObjectInputStream;
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import java.io.ObjectOutputStream;
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import java.util.Arrays;
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import modern.challenge.shallow.copy.matrix.Matrices;
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import org.apache.commons.lang3.SerializationUtils;
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public class Main {
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public static void main(String[] args) throws CloneNotSupportedException {
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// shallow copy via manual copy
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System.out.println("Shallow copy via manual copy:");
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System.out.println("\nShallow copy via manual copy:");
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modern.challenge.shallow.copy.manually.Point point1
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= new modern.challenge.shallow.copy.manually.Point(5, 5);
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@@ -159,6 +161,44 @@ public static void main(String[] args) throws CloneNotSupportedException {
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System.out.println("Clone 7, (x, y, Radius start, Radius end): "
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+ clone7.getX() + ", " + clone7.getY()
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+ ", " + clone7.getRadius().getStart() + ", " + clone7.getRadius().getEnd());
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int[][] source = {{3, 1, 5}, {3, 6, 7}};
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// shallow copy of matrix (1)
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System.out.println("\nShallow copy of matrix via manual copy (1):");
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int[][] target1 = Matrices.cloneArrayOfInt1(source);
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target1[0][0] = 0;
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System.out.println("Original array:");
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printMatrix(source);
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System.out.println("Cloned and modified array:");
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printMatrix(target1);
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// shallow copy of matrix (2)
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System.out.println("\nShallow copy of matrix via manual copy (2):");
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int[][] target2 = 10000 Matrices.cloneArrayOfInt2(source);
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target2[0][0] = 0;
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System.out.println("Original array:");
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printMatrix(source);
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System.out.println("Cloned and modified array:");
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printMatrix(target2);
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// shallow copy of matrix (3)
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System.out.println("\nShallow copy of matrix via manual copy (3):");
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int[][] target3 = Matrices.cloneArrayOfInt3(source);
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target3[0][0] = 0;
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System.out.println("Original array:");
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printMatrix(source);
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System.out.println("Cloned and modified array:");
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printMatrix(target3);
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// shallow copy of matrix (4)
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System.out.println("\nShallow copy of matrix via manual copy (4):");
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int[][] target4 = Matrices.cloneArrayOfInt4(source);
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target4[0][0] = 0;
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System.out.println("Original array:");
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printMatrix(source);
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System.out.println("Cloned and modified array:");
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printMatrix(target4);
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}
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@SuppressWarnings("unchecked")
@@ -182,4 +222,14 @@ private static <T> T cloneThroughSerialization(T t) {
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return t;
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}
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}
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// helper method to display a matrix
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private static void printMatrix(int[][] matrix) {
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for (int i = 0; i < matrix.length; i++) {
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for (int j = 0; j < matrix[0].length; j++) {
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System.out.print(matrix[i][j] + " ");
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}
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System.out.println();
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}
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}
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}

‎Chapter02/P53_CloningObjects/src/main/java/modern/challenge/shallow/copy/matrix/Matrices.java

Lines changed: 61 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,61 @@
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package modern.challenge.shallow.copy.matrix;
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import java.util.Arrays;
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public final class Matrices {
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private Matrices() {
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throw new AssertionError("Cannot be instantiated");
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}
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public static int[][] cloneArrayOfInt1(int[][] source) {
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if (source == null) {
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throw new IllegalArgumentException("The given array cannot be null");
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}
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int length = source.length;
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int[][] target = new int[length][source[0].length];
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for (int i = 0; i < length; i++) {
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target[i] = source[i].clone();
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}
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return target;
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}
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public static int[][] cloneArrayOfInt2(int[][] source) {
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if (source == null) {
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throw new IllegalArgumentException("The given array cannot be null");
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}
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int length = source.length;
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int[][] target = new int[length][source[0].length];
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for (int i = 0; i < length; i++) {
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System.arraycopy(source[i], 0, target[i], 0, source[i].length);
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}
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return target;
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}
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public static int[][] cloneArrayOfInt3(int[][] source) {
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if (source == null) {
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throw new IllegalArgumentException("The given array cannot be null");
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}
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int length = source.length;
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int[][] target = new int[length][];
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for (int i = 0; i < length; i++) {
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target[i] = Arrays.copyOf(source[i], source[i].length);
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}
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return target;
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}
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public static int[][] cloneArrayOfInt4(int[][] source) {
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return Arrays.stream(source)
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.map(int[]::clone)
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.toArray(int[][]::new);
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}
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}

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