Java 8 DoublePredicate Interface
7 years ago Lalit Bhagtani 0
In this tutorial, we will learn about Java 8 DoublePredicate interface.
DoublePredicate Interface :-
DoublePredicate ( java.util.function.DoublePredicate ) is a functional interface that has one abstract method and three default method declared in it. This interface is a specialised form of Predicate interface.
Abstract method :-
boolean test ( double value ) :- The abstract method test ( double value ) is a functional method. It accepts one double value as an argument and return boolean value. It represents a conditional operation, where a passed double value is tested against a specific double value to give a boolean ( True or False ) result.
Default method :-
- default DoublePredicate<T> and ( DoublePredicate <? super T > other ) :- It returns a doublepredicate that represents short circuiting logical AND of this doublepredicate ( doublepredicate on which method is called ) and another ( passed as an argument ).
- default DoublePredicate<T> or ( DoublePredicate <? super T > other ) :- It returns a doublepredicate that represents short circuiting logical OR of this doublepredicate ( doublepredicate on which method is called ) and another ( passed as an argument ).
- default DoublePredicate<T> negate ( ) :- It returns a doublepredicate that represents logical negation of this doublepredicate ( doublepredicate on which method is called ).
Reference :- DoublePredicate Interface JavaDocs
Example :-
This example will show you, how to create and call different methods of a DoublePredicate interface.
public static void main(String[] args){ DoublePredicate doublePredicate1 = ( x ) -> { if( x == 56.66 ){ return true; }else{ return false; }}; // Example of test method boolean result = doublePredicate1.test(56.66); System.out.println(result); // Example of negate method boolean result3 = (doublePredicate1.negate()).test(56.66); System.out.println(result3); DoublePredicate doublePredicate2 = ( x ) -> { if( x == 96.78 ){ return true; }else{ return false; }}; // Example of and method boolean result1 = doublePredicate1.and(doublePredicate2).test(96.78); System.out.println(result1); // Example of or method boolean result2 = doublePredicate2.or(doublePredicate2).test(96.78); System.out.println(result2); }
Result :-
true false false true
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