Java8 Predicate

Predicate

In mathematics, a predicate is commonly understood to be a Boolean-valued function P: X? {true, false}, called the predicate on X. Informally, a predicate is a statement that may be true or false depending on the values of its variables. It can be thought of as an operator or function that returns a value that is either true or false.

Interface Predicate<T>

Type Parameters:
    T - the type of the input to the predicate.

Functional Interface:

This is a functional interface and can therefore be used as the assignment target for a lambda expression or method reference.

@FunctionalInterface

public interface Predicate<T>

Represents a predicate (boolean-valued function) of one argument. This is a functional interface whose functional method is test(Object).

Predicate can be used to evaluate a condition on group/collection of similar objects such that evaluation can result either in true or false.

Method true =

boolean test(T t)
Evaluates this predicate on the given argument.

Parameters:
t - the input argument

Returns
true if the input argument matches the predicate, otherwise false

Example =

public class Main {

        public static void main(String[] args) {
            Predicate<String> i  = (s)-> s.length() > 5;

            System.out.println(i.test("Hi!! How are you?"));
        }
    }

Output

true