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package java.util.function;
import java.util.Objects;
Represents a predicate (boolean-valued function) of one argument.
This is a functional interface whose functional method is test(Object).
Type parameters: - <T> – the type of the input to the predicate
Since: 1.8
/**
* Represents a predicate (boolean-valued function) of one argument.
*
* <p>This is a <a href="package-summary.html">functional interface</a>
* whose functional method is {@link #test(Object)}.
*
* @param <T> the type of the input to the predicate
*
* @since 1.8
*/
@FunctionalInterface
public interface Predicate<T> {
Evaluates this predicate on the given argument.
Params: - t – the input argument
Returns: true if the input argument matches the predicate, otherwise false
/**
* Evaluates this predicate on the given argument.
*
* @param t the input argument
* @return {@code true} if the input argument matches the predicate,
* otherwise {@code false}
*/
boolean test(T t);
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.
Params: - other – a predicate that will be logically-ANDed with this
predicate
Throws: - NullPointerException – if other is null
Returns: a composed predicate that represents the short-circuiting logical AND of this predicate and the other predicate
/**
* 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 {@code false}, then the {@code other}
* predicate is not evaluated.
*
* <p>Any exceptions thrown during evaluation of either predicate are relayed
* to the caller; if evaluation of this predicate throws an exception, the
* {@code other} predicate will not be evaluated.
*
* @param other a predicate that will be logically-ANDed with this
* predicate
* @return a composed predicate that represents the short-circuiting logical
* AND of this predicate and the {@code other} predicate
* @throws NullPointerException if other is null
*/
default Predicate<T> and(Predicate<? super T> other) {
Objects.requireNonNull(other);
return (t) -> test(t) && other.test(t);
}
Returns a predicate that represents the logical negation of this
predicate.
Returns: a predicate that represents the logical negation of this
predicate
/**
* Returns a predicate that represents the logical negation of this
* predicate.
*
* @return a predicate that represents the logical negation of this
* predicate
*/
default Predicate<T> negate() {
return (t) -> !test(t);
}
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.
Params: - other – a predicate that will be logically-ORed with this
predicate
Throws: - NullPointerException – if other is null
Returns: a composed predicate that represents the short-circuiting logical OR of this predicate and the other predicate
/**
* 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 {@code true}, then the {@code other}
* predicate is not evaluated.
*
* <p>Any exceptions thrown during evaluation of either predicate are relayed
* to the caller; if evaluation of this predicate throws an exception, the
* {@code other} predicate will not be evaluated.
*
* @param other a predicate that will be logically-ORed with this
* predicate
* @return a composed predicate that represents the short-circuiting logical
* OR of this predicate and the {@code other} predicate
* @throws NullPointerException if other is null
*/
default Predicate<T> or(Predicate<? super T> other) {
Objects.requireNonNull(other);
return (t) -> test(t) || other.test(t);
}
Returns a predicate that tests if two arguments are equal according to Objects.equals(Object, Object). Params: - targetRef – the object reference with which to compare for equality, which may be
null
Type parameters: - <T> – the type of arguments to the predicate
Returns: a predicate that tests if two arguments are equal according to Objects.equals(Object, Object)
/**
* Returns a predicate that tests if two arguments are equal according
* to {@link Objects#equals(Object, Object)}.
*
* @param <T> the type of arguments to the predicate
* @param targetRef the object reference with which to compare for equality,
* which may be {@code null}
* @return a predicate that tests if two arguments are equal according
* to {@link Objects#equals(Object, Object)}
*/
static <T> Predicate<T> isEqual(Object targetRef) {
return (null == targetRef)
? Objects::isNull
: object -> targetRef.equals(object);
}
Returns a predicate that is the negation of the supplied predicate. This is accomplished by returning result of the calling target.negate(). Params: - target – predicate to negate
Type parameters: - <T> – the type of arguments to the specified predicate
Throws: - NullPointerException – if target is null
Returns: a predicate that negates the results of the supplied
predicate Since: 11
/**
* Returns a predicate that is the negation of the supplied predicate.
* This is accomplished by returning result of the calling
* {@code target.negate()}.
*
* @param <T> the type of arguments to the specified predicate
* @param target predicate to negate
*
* @return a predicate that negates the results of the supplied
* predicate
*
* @throws NullPointerException if target is null
*
* @since 11
*/
@SuppressWarnings("unchecked")
static <T> Predicate<T> not(Predicate<? super T> target) {
Objects.requireNonNull(target);
return (Predicate<T>)target.negate();
}
}