What is the LongPredicate functional interface in Java?
LongPredicate is a functional interface which accepts a long valued argument and returns a boolean value. This interface has the following methods:
test(long value)and(LongPredicate other)negate()or(LongPredicate other)
The LongPredicate interface is defined in the java.util.function package. To import the LongPredicate interface, we will check the following import statement:
import java.util.function.LongPredicate;
What is test(long value)?
The test(long value) method is used to test a given long valued input on certain evaluations.
Syntax
boolean test(long value)
Parameters
long value: This is thelongvalued input that needs to be evaluated.
Return value
This method returns the result of the evaluation.
Code
import java.util.function.LongPredicate;public class Main{public static void main(String[] args) {// LongPredicate to check if the long valued argument is evenLongPredicate isEven = arg -> arg % 2 == 0;// test whether 4 is evenSystem.out.println(isEven.test(4));// test whether 3 is evenSystem.out.println(isEven.test(3));}}
What is and(LongPredicate other)?
The and(LongPredicate other) method is used to chain multiple implementations of the LongPredicate together as a short-circuiting logical AND operation. If any implementation returns False during the evaluation, then the subsequent implementations will not be invoked.
Syntax
default LongPredicate and(LongPredicate other)
Parameters
LongPredicate other: This is theLongPredicateimplementation that’s used for logicalANDoperation.
Return value
This method returns a composed predicate.
Code
import java.util.function.LongPredicate;;public class Main{public static void main(String[] args) {// LongPredicate to check if the long valued argument is evenLongPredicate isEven = arg -> arg % 2 == 0;// LongPredicate to check if the long valued argument is less than 100LongPredicate isLessThanHundred = arg -> arg < 100;// Composed LongPredicateLongPredicate composedPredicate = isEven.and(isLessThanHundred);// test whether 4 is even and less than 100System.out.println(composedPredicate.test(4));// test whether 103 is even and less than 100System.out.println(composedPredicate.test(103));}}
What is negate()?
The negate() method is used to return a LongPredicate that is a negation of the given LongPredicate.
Syntax
default LongPredicate negate()
Parameters
This method has no parameters.
Return value
This method returns a predicate.
Code
import java.util.function.LongPredicate;public class Main{public static void main(String[] args) {// LongPredicate to check if the long valued argument is evenLongPredicate isEven = arg -> arg % 2 == 0;// LongPredicate to get the Opposite of even using the negate methodLongPredicate isEvenNegate = isEven.negate();// test negation on 4System.out.println(isEvenNegate.test(4));// test negation on 3System.out.println(isEvenNegate.test(3));}}
What is or(LongPredicate other)?
The or(LongPredicate other) method is used to chain multiple implementations of LongPredicate together as a short-circuiting logical OR operation. If any implementation returns True during the evaluation, then the subsequent implementations will not be invoked.
Syntax
default LongPredicate or(LongPredicate other)
Parameters
LongPredicate other: This is theLongPredicateimplementation that’s used for logical OR operation.
Return value
This method returns a composed predicate.
Code
import java.util.function.LongPredicate;public class Main{public static void main(String[] args) {// LongPredicate to check if the long valued argument is evenLongPredicate isEven = arg -> arg % 2 == 0;// LongPredicate to check if the long valued argument is less than 100LongPredicate isLessThanHundred = arg -> arg < 100;// Composed LongPredicateLongPredicate composedPredicate = isEven.or(isLessThanHundred);// test whether 4 is even and less than 100System.out.println(composedPredicate.test(4));// test whether 103 is even and less than 100System.out.println(composedPredicate.test(103));}}