Interface Predicate<T>

  • All Superinterfaces:
    All Known Implementing Classes:
    BloomFilter, CharMatcher, Range
    Functional Interface:
    This is a functional interface and can therefore be used as the assignment target for a lambda expression or method reference.

    public interface Predicate<T>
    extends Predicate<T>
    Legacy version of java.util.function.Predicate. Determines a true or false value for a given input.

    As this interface extends java.util.function.Predicate, an instance of this type may be used as a Predicate directly. To use a java.util.function.Predicate where a is expected, use the method reference predicate::test.

    This interface is now a legacy type. Use java.util.function.Predicate (or the appropriate primitive specialization such as IntPredicate) instead whenever possible. Otherwise, at least reduce explicit dependencies on this type by using lambda expressions or method references instead of classes, leaving your code easier to migrate in the future.

    The Predicates class provides common predicates and related utilities.

    See the Guava User Guide article on the use of Predicate.

    Kevin Bourrillion
    • Method Detail

      • apply

        boolean apply​(@Nullable T input)
        Returns the result of applying this predicate to input (Java 8 users, see notes in the class documentation above). This method is generally expected, but not absolutely required, to have the following properties:
        • Its execution does not cause any observable side effects.
        • The computation is consistent with equals; that is, Objects.equal(a, b) implies that predicate.apply(a) == predicate.apply(b)).
        NullPointerException - if input is null and this predicate does not accept null arguments
      • equals

        boolean equals​(@Nullable Object object)
        Indicates whether another object is equal to this predicate.

        Most implementations will have no reason to override the behavior of Object.equals(java.lang.Object). However, an implementation may also choose to return true whenever object is a Predicate that it considers interchangeable with this one. "Interchangeable" typically means that this.apply(t) == that.apply(t) for all t of type T). Note that a false result from this method does not imply that the predicates are known not to be interchangeable.

        equals in class Object
        object - the reference object with which to compare.
        true if this object is the same as the obj argument; false otherwise.
        See Also:
        Object.hashCode(), HashMap
      • test

        default boolean test​(@Nullable T input)
        Description copied from interface: java.util.function.Predicate
        Evaluates this predicate on the given argument.
        Specified by:
        test in interface Predicate<T>
        input - the input argument
        true if the input argument matches the predicate, otherwise false