Java 8 Predicate Chaining using and() or() and negate() Methods

We can chain instances of Predicate functional interfaces together to create complex conditions by using methods and(), or(), and negate().

Let's take a look with an example.

package org.code2care.examples;

import java.util.function.Predicate;

public class Java8PredicateChainingExample {

    public static void main(String... args) {

        Predicate<Integer> isEven = num -> num % 2 == 0;
        Predicate<Integer> isPositive = num -> num > 0;

        //Chaining using and() or() and negate()
        Predicate<Integer> isEvenAndPositive = isEven.and(isPositive);
        Predicate<Integer> isEvenOrPositive = isEven.or(isPositive);
        Predicate<Integer> isNotEven = isEven.negate();

        int testNumber1 = 16;
        int testNumber2 = -13;

        boolean result1 = isEvenAndPositive.test(testNumber1);
        boolean result2 = isEvenAndPositive.test(testNumber2);

        boolean result3 = isEvenOrPositive.test(testNumber1);
        boolean result4 = isEvenOrPositive.test(testNumber2);

        boolean result5 = isNotEven.test(testNumber1);

        System.out.println(testNumber1 + " is even and positive: " + result1);
        System.out.println(testNumber2 + " is even and positive: " + result2);
        System.out.println(testNumber1 + " is even or positive: " + result3);
        System.out.println(testNumber2 + " is even or positive: " + result4);
        System.out.println(testNumber1 + " is not even: " + result5);
    }
}