October 10, 2020

java.util.function.IntBinaryOperator implementation in modern Java

In this blog post, I will show you the different ways to implement java.util.function.IntBinaryOperator.

You can watch my youtube video, where I code these implementation.

A Regular Class..

private class RegularImpl implements IntBinaryOperator{
public int applyAsInt(final int firstIntValue, final int secondIntValue){
    return firstIntValue > secondIntValue ? firstIntValue : secondIntValue;

Implementation using a regular class is the same way of implementation that we have always been doing in Java.

Implementation using an anonymous class

private IntBinaryOperator sum = new IntBinaryOperator() { 
                      public int applyAsInt(final int firstValue, final int secondValue){
                          return firstValue + secondValue;

The anonymous way of implementing an interface is the same old way. Where we create an instance, and we provide implementation in the curly braces.

Now, we take a look at Lambda implementation

private IntBinaryOperator sumLam_1 = (int firstValue, int secondValue) -> { return firstValue + secondValue; };

The above implementation looks like a function without any name. It is a hybrid between a variable declaration and a function definition.

In next Lambda implementation, we can remove the data-type of the variables. As, compiler is able to figure out the data-type of these parameters from the function declaration of applyAsInt inside the IntBinaryOperator.

private IntBinaryOperator sumLam_2 = (firstValue, secondValue) -> firstValue + secondValue;

The next implementation uses method reference, where we use Class or Instance name followed by ::  and name of the method.

private IntBinaryOperator sumLam_3 = Integer::sum;

The above implementation is not a fresh implementation, it delegates all calls to sum method in Integer class.