Module java.base

Package java.util.function

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).

Since:

1.8

Method Summary

Modifier and Type	Method	Description
default Predicate<T>	and(Predicate<? super T> other)	Returns a composed predicate that represents a short-circuiting logical AND of this predicate and another.
static <T> Predicate<T>	isEqual(Object targetRef)	Returns a predicate that tests if two arguments are equal according to Objects.equals(Object, Object).
default Predicate<T>	negate()	Returns a predicate that represents the logical negation of this predicate.
static <T> Predicate<T>	not(Predicate<? super T> target)	Returns a predicate that is the negation of the supplied predicate.
default Predicate<T>	or(Predicate<? super T> other)	Returns a composed predicate that represents a short-circuiting logical OR of this predicate and another.
boolean	test(T t)	Evaluates this predicate on the given argument.

Method Detail

test

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

and

default Predicate<T> and(Predicate<? super T> other)

Returns a composed predicate that represents a short-circuiting logical AND of this predicate and another. When evaluating the composed predicate, if this predicate is false, then the other predicate is not evaluated.

Any exceptions thrown during evaluation of either predicate are relayed to the caller; if evaluation of this predicate throws an exception, the other predicate will not be evaluated.

Parameters:

other - a predicate that will be logically-ANDed with this predicate

Returns:

a composed predicate that represents the short-circuiting logical AND of this predicate and the other predicate

Throws:

NullPointerException - if other is null

negate

default Predicate<T> negate()

Returns a predicate that represents the logical negation of this predicate.

Returns:

a predicate that represents the logical negation of this predicate

or

default Predicate<T> or(Predicate<? super T> other)

Returns a composed predicate that represents a short-circuiting logical OR of this predicate and another. When evaluating the composed predicate, if this predicate is true, then the other predicate is not evaluated.

Any exceptions thrown during evaluation of either predicate are relayed to the caller; if evaluation of this predicate throws an exception, the other predicate will not be evaluated.

Parameters:

other - a predicate that will be logically-ORed with this predicate

Returns:

a composed predicate that represents the short-circuiting logical OR of this predicate and the other predicate

Throws:

NullPointerException - if other is null

isEqual

static <T> Predicate<T> isEqual(Object targetRef)

Returns a predicate that tests if two arguments are equal according to Objects.equals(Object, Object).

Type Parameters:

T - the type of arguments to the predicate

Parameters:

targetRef - the object reference with which to compare for equality, which may be null

Returns:

a predicate that tests if two arguments are equal according to Objects.equals(Object, Object)

not

static <T> Predicate<T> not(Predicate<? super T> target)

Returns a predicate that is the negation of the supplied predicate. This is accomplished by returning result of the calling target.negate().

Type Parameters:

T - the type of arguments to the specified predicate

Parameters:

target - predicate to negate

Returns:

a predicate that negates the results of the supplied predicate

Throws:

NullPointerException - if target is null

Since:

11