Java BiPredicate guide + Examples

Java BiPredicate represents a Predicate (boolean-valued function) of two arguments and returns boolean value. This is a functional interface and can therefore be used as the assignment target for a lambda expression or method reference. BiPredicate functional method is test(Object, Object)

A Basic BiPredicate example :

public class BiPredicateTest {

	public static void main(String[] args) {

		// A basic BiPredicate usage
		BiPredicate<Integer, Integer> p = (n1, n2) -> n1 > n2;

		System.out.println(p.test(20, 10));// true
		System.out.println(p.test(12, 24));// false

	}
}

Output :

true
false

1. Java BiPredicate methods and Examples

1. boolean test(T t, U u) – Evaluates this predicate on the given arguments.
2. default BiPredicate or(BiPredicate other) – Returns a composed predicate that represents a short-circuiting logical OR of this predicate and another.
3. default BiPredicate negate() – Returns a predicate that represents the logical negation of this predicate.
4. default BiPredicate and(BiPredicate other) – Returns a composed predicate that represents a short-circuiting logical AND of this predicate and another

1.1. BiPredicate and() example

The following basic example demonstrates how BiPredicate and() method works.

public class BiPredicateAndTest {

	public static void main(String[] args) {

		BiPredicate<Integer, Integer> bp1 = (n1, n2) -> (n1 % n2 == 0);
		BiPredicate<Integer, Integer> bp2 = (n1, n2) -> (n1 * n2 > 100);

		// n1 should divisible by n2 and n1*n2 greater than 100
		System.out.println(bp1.and(bp2).test(120, 6)); // flase

		BiPredicate<String, String> bp3 = (s1, s2) -> s1.startsWith(s2);
		BiPredicate<String, Integer> bp4 = (s1, s2) -> s1.length() > s2;
		BiPredicate<String, String> bp5 = (s1, s2) -> s1.endsWith(s2);

		// System.out.println(bp3.and(bp4).test("ANAND", "D")); // incompatible types

		// s1 should starts with "P" and ends with "P"
		System.out.println(bp3.and(bp5).test("Peter", "P")); // false

		// s1 should starts with "A" and end with "A"
		System.out.println(bp3.and(bp5).test("ASHJA", "A")); // true
	}
}

Output :

true
false
true

1.2. BiPredicate or() example

The following basic example demonstrates how BiPredicate or() method works.

public class BiPredicateOrTest {

	public static void main(String[] args) {

		BiPredicate<Integer, Integer> bp1 = (n1, n2) -> (n1 % n2 == 0);
		BiPredicate<Integer, Integer> bp2 = (n1, n2) -> (n1 * n2 > 100);

		// n1 should be divisible by n2 or greater than 100
		System.out.println(bp1.or(bp2).test(120, 7)); // true
		System.out.println(bp1.or(bp2).test(13, 5)); // false

		BiPredicate<String, String> bp3 = (s1, s2) -> s1.startsWith(s2);
		BiPredicate<String, Integer> bp4 = (s1, s2) -> s1.length() > 5;
		BiPredicate<String, String> bp5 = (s1, s2) -> s1.endsWith(s2);

		// name starts with "A" or not ends with "p"
		// System.out.println(bp3.or(bp4)); // bp3 and bp4 are incompatible types

		System.out.println(bp3.or(bp5).test("Peter", "r")); // true
		System.out.println(bp3.or(bp5).test("Anand", "A")); // true
	}
}

Output :

true
false
true
true

1.3. BiPredicate negate() example

The following basic example demonstrates how BiPredicate negate() method works.

public class BiPredicateNegateTest {

	public static void main(String[] args) {

		BiPredicate<Integer, Integer> bp1 = (n1, n2) -> (n1 % n2 == 0);
		BiPredicate<Integer, Integer> bp2 = (n1, n2) -> (n1 * n2 > 100);

		// n1 should not be divisible by n2 and n1*n2 not greater than 100
		System.out.println(bp1.negate().test(120, 6)); // flase
		System.out.println(bp2.negate().test(12, 7)); // true

		BiPredicate<String, String> bp3 = (s1, s2) -> s1.startsWith(s2);
		BiPredicate<String, Integer> bp4 = (s1, s2) -> s1.length() > s2;
		BiPredicate<String, String> bp5 = (s1, s2) -> s1.endsWith(s2);

		// s1 should not starts with s2
		System.out.println(bp3.negate().test("ANAND", "D")); // true

		// s1 lengthe should not greater than s2
		System.out.println(bp4.negate().test("PETER", 5)); // true

		// s1 should not ends with s2
		System.out.println(bp5.negate().test("ASHJA", "A")); // false
	}
}

false
true
true
true
false

Conclusion

BiPredicate is a built-in java functional interface which takes two arguments and return a boolean value. In this article we have covered about Java BiPredicate interface and methods of it with basic examples.

References

1. Java document
2. Java Predicate interface