BAEL-3091: The Prototype Pattern in Java

patterns/design-patterns-creational/src/main/java/com/baeldung/prototype/Position.java

@@ -0,0 +1,51 @@
+package com.baeldung.prototype;
+
+public final class Position {
+
+    private final int x;
+    private final int y;
+
+    public Position(int x, int y) {
+        this.x = x;
+        this.y = y;
+    }
+
+    public int getX() {
+        return x;
+    }
+
+    public int getY() {
+        return y;
+    }
+
+    @Override
+    public int hashCode() {
+        final int prime = 31;
+        int result = 1;
+        result = prime * result + x;
+        result = prime * result + y;
+        return result;
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj)
+            return true;
+        if (obj == null)
+            return false;
+        if (getClass() != obj.getClass())
+            return false;
+        Position other = (Position) obj;
+        if (x != other.x)
+            return false;
+        if (y != other.y)
+            return false;
+        return true;
+    }
+
+    @Override
+    public String toString() {
+        return "Position [x=" + x + ", y=" + y + "]";
+    }
+
+}

patterns/design-patterns-creational/src/main/java/com/baeldung/prototype/Tree.java

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+package com.baeldung.prototype;
+
+public class Tree implements TreeCloneable {
+
+    private double mass;
+    private double height;
+    private Position position;
+
+    public Tree(double mass, double height) {
+        this.mass = mass;
+        this.height = height;
+    }
+
+    public void setMass(double mass) {
+        this.mass = mass;
+    }
+
+    public void setHeight(double height) {
+        this.height = height;
+    }
+
+    public void setPosition(Position position) {
+        this.position = position;
+    }
+
+    public double getMass() {
+        return mass;
+    }
+
+    public double getHeight() {
+        return height;
+    }
+
+    public Position getPosition() {
+        return position;
+    }
+
+    @Override
+    public TreeCloneable createA_Clone() {
+        TreeCloneable tree = null;
+        try {
+            tree = (TreeCloneable) super.clone();
+        } catch (CloneNotSupportedException e) {
+            e.printStackTrace();
+        }
+        return tree;
+    }
+
+    @Override
+    public String toString() {
+        return "SomeTree [mass=" + mass + ", height=" + height + ", position=" + position + "]";
+    }
+
+}

patterns/design-patterns-creational/src/main/java/com/baeldung/prototype/TreeCloneable.java

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+package com.baeldung.prototype;
+
+public interface TreeCloneable extends Cloneable {
+
+    public TreeCloneable createA_Clone();
+
+}

patterns/design-patterns-creational/src/test/java/com/baeldung/prototype/TreePrototypeUnitTest.java

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+package com.baeldung.prototype;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+public class TreePrototypeUnitTest {
+
+    @Test
+    public void givenATreePrototypeWhenClonedThenCreateA_Clone() {
+        double mass = 10.0;
+        double height = 3.7;
+        Position position = new Position(3, 7);
+        Position otherPosition = new Position(4, 8);
+        
+        Tree tree = new Tree(mass, height);
+        tree.setPosition(position);
+        Tree anotherTree = (Tree) tree.createA_Clone();
+        anotherTree.setPosition(otherPosition);
+
+        assertEquals(position, tree.getPosition());
+        assertEquals(otherPosition, anotherTree.getPosition());
+    }
+}