程序包 java.util.function

接口 Predicate<T>

类型参数:

T - the type of the input to the predicate

函数接口:

这是一个函数接口, 因此可用作 lambda 表达式或方法引用的赋值目标。

@FunctionalInterface
public interface Predicate<T>

Represents a predicate (boolean-valued function) of one argument.

This is a functional interface whose functional method is test(java.lang.Object).

从以下版本开始:

1.8

方法概要

限定符和类型	方法	说明
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.
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.

方法详细资料

test

boolean test(T t)

Evaluates this predicate on the given argument.

参数:

t - the input argument

返回:

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.

参数:

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

返回:

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

抛出:

NullPointerException - if other is null

negate

default Predicate<T> negate()

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

返回:

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.

参数:

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

返回:

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

抛出:

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).

类型参数:

T - the type of arguments to the predicate

参数:

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

返回:

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