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 Details

    • 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