Added equals()/hashcode() (#646)

eclipse/src/main/java/org/baeldung/equalshashcode/entities/ComplexClass.java

@@ -0,0 +1,67 @@
+package org.baeldung.equalshashcode.entities;
+
+import java.util.ArrayList;
+import java.util.HashSet;
+
+public class ComplexClass {
+
+	private ArrayList<?> genericArrayList;
+	private HashSet<Integer> integerHashSet;
+
+	public ComplexClass(ArrayList<?> genericArrayList,
+			HashSet<Integer> integerHashSet) {
+		super();
+		this.genericArrayList = genericArrayList;
+		this.integerHashSet = integerHashSet;
+	}
+
+	@Override
+	public int hashCode() {
+		final int prime = 31;
+		int result = 1;
+		result = prime
+				* result
+				+ ((genericArrayList == null) ? 0 : genericArrayList.hashCode());
+		result = prime * result
+				+ ((integerHashSet == null) ? 0 : integerHashSet.hashCode());
+		return result;
+	}
+
+	@Override
+	public boolean equals(Object obj) {
+		if (this == obj)
+			return true;
+		if (obj == null)
+			return false;
+		if (!(obj instanceof ComplexClass))
+			return false;
+		ComplexClass other = (ComplexClass) obj;
+		if (genericArrayList == null) {
+			if (other.genericArrayList != null)
+				return false;
+		} else if (!genericArrayList.equals(other.genericArrayList))
+			return false;
+		if (integerHashSet == null) {
+			if (other.integerHashSet != null)
+				return false;
+		} else if (!integerHashSet.equals(other.integerHashSet))
+			return false;
+		return true;
+	}
+
+	protected ArrayList<?> getGenericArrayList() {
+		return genericArrayList;
+	}
+
+	protected void setGenericArrayList(ArrayList<?> genericArrayList) {
+		this.genericArrayList = genericArrayList;
+	}
+
+	protected HashSet<Integer> getIntegerHashSet() {
+		return integerHashSet;
+	}
+
+	protected void setIntegerHashSet(HashSet<Integer> integerHashSet) {
+		this.integerHashSet = integerHashSet;
+	}
+}

eclipse/src/main/java/org/baeldung/equalshashcode/entities/PrimitiveClass.java

@@ -0,0 +1,54 @@
+package org.baeldung.equalshashcode.entities;
+
+public class PrimitiveClass {
+
+	private boolean primitiveBoolean;
+	private int primitiveInt;
+
+	public PrimitiveClass(boolean primitiveBoolean, int primitiveInt) {
+		super();
+		this.primitiveBoolean = primitiveBoolean;
+		this.primitiveInt = primitiveInt;
+	}
+
+	protected boolean isPrimitiveBoolean() {
+		return primitiveBoolean;
+	}
+
+	@Override
+	public int hashCode() {
+		final int prime = 31;
+		int result = 1;
+		result = prime * result + (primitiveBoolean ? 1231 : 1237);
+		result = prime * result + primitiveInt;
+		return result;
+	}
+
+	@Override
+	public boolean equals(Object obj) {
+		if (this == obj)
+			return true;
+		if (obj == null)
+			return false;
+		if (getClass() != obj.getClass())
+			return false;
+		PrimitiveClass other = (PrimitiveClass) obj;
+		if (primitiveBoolean != other.primitiveBoolean)
+			return false;
+		if (primitiveInt != other.primitiveInt)
+			return false;
+		return true;
+	}
+
+	protected void setPrimitiveBoolean(boolean primitiveBoolean) {
+		this.primitiveBoolean = primitiveBoolean;
+	}
+
+	protected int getPrimitiveInt() {
+		return primitiveInt;
+	}
+
+	protected void setPrimitiveInt(int primitiveInt) {
+		this.primitiveInt = primitiveInt;
+	}
+}

eclipse/src/main/java/org/baeldung/equalshashcode/entities/Rectangle.java

@@ -0,0 +1,62 @@
+package org.baeldung.equalshashcode.entities;
+
+public class Rectangle extends Shape {
+	private double width;
+	private double length;
+
+	public Rectangle(double width, double length) {
+		this.width = width;
+		this.length = length;
+	}
+
+	@Override
+	public double area() {
+		// A = w * l
+		return width * length;
+	}
+
+	@Override
+	public double perimeter() {
+		// P = 2(w + l)
+		return 2 * (width + length);
+	}
+
+	@Override
+	public int hashCode() {
+		final int prime = 31;
+		int result = 1;
+		long temp;
+		temp = Double.doubleToLongBits(length);
+		result = prime * result + (int) (temp ^ (temp >>> 32));
+		temp = Double.doubleToLongBits(width);
+		result = prime * result + (int) (temp ^ (temp >>> 32));
+		return result;
+	}
+
+	@Override
+	public boolean equals(Object obj) {
+		if (this == obj)
+			return true;
+		if (obj == null)
+			return false;
+		if (getClass() != obj.getClass())
+			return false;
+		Rectangle other = (Rectangle) obj;
+		if (Double.doubleToLongBits(length) != Double
+				.doubleToLongBits(other.length))
+			return false;
+		if (Double.doubleToLongBits(width) != Double
+				.doubleToLongBits(other.width))
+			return false;
+		return true;
+	}
+
+	protected double getWidth() {
+		return width;
+	}
+
+	protected double getLength() {
+		return length;
+	}
+
+}

eclipse/src/main/java/org/baeldung/equalshashcode/entities/Shape.java

@@ -0,0 +1,7 @@
+package org.baeldung.equalshashcode.entities;
+
+public abstract class Shape {
+	public abstract double area();
+
+	public abstract double perimeter();
+}

eclipse/src/main/java/org/baeldung/equalshashcode/entities/Square.java

@@ -0,0 +1,47 @@
+package org.baeldung.equalshashcode.entities;
+
+import java.awt.Color;
+
+public class Square extends Rectangle {
+
+	Color color;
+
+	public Square(double width, Color color) {
+		super(width, width);
+		this.color = color;
+	}
+
+	@Override
+	public int hashCode() {
+		final int prime = 31;
+		int result = super.hashCode();
+		result = prime * result + ((color == null) ? 0 : color.hashCode());
+		return result;
+	}
+
+	@Override
+	public boolean equals(Object obj) {
+		if (this == obj)
+			return true;
+		if (!super.equals(obj))
+			return false;
+		if (getClass() != obj.getClass())
+			return false;
+		Square other = (Square) obj;
+		if (color == null) {
+			if (other.color != null)
+				return false;
+		} else if (!color.equals(other.color))
+			return false;
+		return true;
+	}
+
+	protected Color getColor() {
+		return color;
+	}
+
+	protected void setColor(Color color) {
+		this.color = color;
+	}
+
+}

eclipse/src/test/java/org/baeldung/equalshashcode/entities/ComplexClassTest.java

@@ -0,0 +1,39 @@
+package org.baeldung.equalshashcode.entities;
+
+import java.util.ArrayList;
+import java.util.HashSet;
+
+import org.junit.Assert;
+import org.junit.Test;
+
+public class ComplexClassTest {
+
+	@Test
+	public void testEqualsAndHashcodes() {
+		
+		ArrayList<String> strArrayList = new ArrayList<String>();
+		strArrayList.add("abc");
+		strArrayList.add("def");
+		ComplexClass aObject = new ComplexClass(strArrayList, new HashSet<Integer>(45,67));
+		ComplexClass bObject = new ComplexClass(strArrayList, new HashSet<Integer>(45,67));
+		ComplexClass cObject = new ComplexClass(strArrayList, new HashSet<Integer>(45,67));
+		
+		ArrayList<String> strArrayListD = new ArrayList<String>();
+		strArrayListD.add("lmn");
+		strArrayListD.add("pqr");
+		ComplexClass dObject = new ComplexClass(strArrayListD, new HashSet<Integer>(45,67));
+		
+		// equals()
+		Assert.assertTrue(aObject.equals(aObject));
+		Assert.assertTrue(aObject.equals(bObject) && bObject.equals(aObject));
+		Assert.assertTrue(aObject.equals(bObject));
+		Assert.assertTrue(bObject.equals(cObject));
+		Assert.assertTrue(aObject.equals(cObject));
+		// hashCode()
+		Assert.assertTrue(aObject.hashCode() == bObject.hashCode());
+		// non-equal objects are not equals() and have different hashCode()
+		Assert.assertFalse(aObject.equals(dObject));
+		Assert.assertFalse(aObject.hashCode() == dObject.hashCode());
+	}
+
+}

eclipse/src/test/java/org/baeldung/equalshashcode/entities/PrimitiveClassTest.java

@@ -0,0 +1,29 @@
+package org.baeldung.equalshashcode.entities;
+
+import org.junit.Assert;
+import org.junit.Test;
+
+public class PrimitiveClassTest {
+
+	@Test
+	public void testTwoEqualsObjects() {
+
+		PrimitiveClass aObject = new PrimitiveClass(false, 2);
+		PrimitiveClass bObject = new PrimitiveClass(false, 2);
+		PrimitiveClass cObject = new PrimitiveClass(false, 2);
+		PrimitiveClass dObject = new PrimitiveClass(true, 2);
+
+		// equals()
+		Assert.assertTrue(aObject.equals(aObject));
+		Assert.assertTrue(aObject.equals(bObject) && bObject.equals(aObject));
+		Assert.assertTrue(aObject.equals(bObject));
+		Assert.assertTrue(bObject.equals(cObject));
+		Assert.assertTrue(aObject.equals(cObject));
+		// hashCode()
+		Assert.assertTrue(aObject.hashCode() == bObject.hashCode());
+		// non-equal objects are not equals() and have different hashCode()
+		Assert.assertFalse(aObject.equals(dObject));
+		Assert.assertFalse(aObject.hashCode() == dObject.hashCode());
+	}
+
+}

eclipse/src/test/java/org/baeldung/equalshashcode/entities/SquareClassTest.java

@@ -0,0 +1,32 @@
+package org.baeldung.equalshashcode.entities;
+
+import java.awt.Color;
+
+import org.junit.Assert;
+import org.junit.Test;
+
+public class SquareClassTest {
+
+	@Test
+	public void testEqualsAndHashcodes() {
+		
+		Square aObject = new Square(10, Color.BLUE);
+		Square bObject = new Square(10, Color.BLUE);
+		Square cObject = new Square(10, Color.BLUE);
+		
+		Square dObject = new Square(20, Color.BLUE);
+		
+		// equals()
+		Assert.assertTrue(aObject.equals(aObject));
+		Assert.assertTrue(aObject.equals(bObject) && bObject.equals(aObject));
+		Assert.assertTrue(aObject.equals(bObject));
+		Assert.assertTrue(bObject.equals(cObject));
+		Assert.assertTrue(aObject.equals(cObject));		
+		// hashCode()
+		Assert.assertTrue(aObject.hashCode() == bObject.hashCode());		
+		// non-equal objects are not equals() and have different hashCode()
+		Assert.assertFalse(aObject.equals(dObject));
+		Assert.assertFalse(aObject.hashCode() == dObject.hashCode());
+	}
+
+}