What is the BiPredicate in Java 8

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Last updated on February 29th, 2024

Normal Predicate predefined functional interface that accepts only one input and returns a boolean result. But if we provide two inputs to the Predicate, it is not accepted. That’s why Java 8 introduced a BiPredicate predefined functional interface. It accepts two inputs and returns a boolean result. This predefined functional interface is available in the java.util.function package.
Prototype:

interface BiPredicate<T, U>{
public boolean test(T t, U u);

}

Type Parameters:
T – It is the type of the first argument to the predicate
U – It is the type of the second argument the predicate
BiPredicate Example:

import java.util.function.BiPredicate;

public class Test {

public static void main(String[] args) {

BiPredicate<String, Integer> bi = (a, b) -> {

return a.length() == b;

};

boolean result = bi.test("Peter", 5);

System.out.println(result);

boolean result1 = bi.test("Robert", 4);

System.out.println(result1);

boolean result2 = bi.test("William", 7);

System.out.println(result2);
      }
}

Output:

true
false
true

BiPredicate Methods:
    • boolean test(T t, U u): This method evaluates this predicate on the given arguments
    • default BiPredicate or(BiPredicate other): This method returns a composed predicate that represents a short-circuiting logical OR of this predicate and another
    • default BiPredicate and(BiPredicate other):  This method returns a composed predicate that represents a short-circuiting logical AND of this predicate and another
    • default BiPredicate negate():  This method returns a predicate that represents the logical negation of this predicate
BiPredicate and() example:

import java.util.function.BiPredicate;

public class Test {

public static void main(String[] args) {

BiPredicate<Integer, Integer> bi1 = (a, b) -> a%b==0;

BiPredicate<Integer, Integer> bi2 = (a, b) -> a*b<50;

System.out.println("The a is divisible by b and a*b is less than 50: "+bi1.and(bi2).test(10, 2));

System.out.println("The a is divisible by b and a*b is less than 50: "+bi1.and(bi2).test(30, 9));

System.out.println("The a is divisible by b and a*b is less than 50: "+bi1.and(bi2).test(50, 2));
     }
}

Output: 

The a is divisible by b and a*b is less than 50: true
The a is divisible by b and a*b is less than 50: false
The a is divisible by b and a*b is less than 50: false

BiPredicate or() example:

import java.util.function.BiPredicate;

public class Test {

public static void main(String[] args) {

BiPredicate<Integer, Integer> bi1 = (a, b) -> a%b==0;

BiPredicate<Integer, Integer> bi2 = (a, b) -> a*b<50;

System.out.println("The a is divisible by b or a*b is less than 50: "+bi1.or(bi2).test(10, 2));

System.out.println("The a is divisible by b or a*b is less than 50: "+bi1.or(bi2).test(30, 9));

System.out.println("The a is divisible by b or a*b is less than 50: "+bi1.or(bi2).test(50, 2));
   }
}

Output: 

The a is divisible by b or a*b is less than 50: true
The a is divisible by b or a*b is less than 50: false
The a is divisible by b or a*b is less than 50: true

BiPredicate negate() example:

import java.util.function.BiPredicate;

public class Test {

public static void main(String[] args) {

BiPredicate<Integer, Integer> bi1 = (a, b) -> a%b==0;

BiPredicate<Integer, Integer> bi2 = (a, b) -> a*b<50;

System.out.println("The a is not divisible by b or a*b is not less than 50: "+bi1.negate().test(10, 2));

System.out.println("The a is not divisible by b or a*b is not less than 50: "+bi2.negate().test(30, 9));

System.out.println("The a is not divisible by b or a*b is not less than 50: "+bi1.negate().test(50, 2));
    }
}

Output: 

The a is not divisible by b or a*b is not less than 50: false
The a is not divisible by b or a*b is not less than 50: true
The a is not divisible by b or a*b is not less than 50: false

Conclusion:
This topic is explained What is a BiPredicate? What are the methods of it? How to use it?

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