com.google.common.base

Interface Predicate<T>

All Superinterfaces:

Predicate<T>

Functional Interface:

This is a functional interface and can therefore be used as the assignment target for a lambda expression or method reference.

@FunctionalInterface
 @GwtCompatible
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 com.google.common.base.Predicate 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.

Since:

2.0

Author:

Kevin Bourrillion

Method Summary

Modifier and Type	Method and Description
boolean	apply(T input) Returns the result of applying this predicate to input (Java 8 users, see notes in the class documentation above).
boolean	equals(Object object) Indicates whether another object is equal to this predicate.
default boolean	test(T input) Evaluates this predicate on the given argument.

Methods inherited from interface java.util.function.Predicate

and, isEqual, negate, or

Method Detail

apply

@CanIgnoreReturnValue
boolean apply(@NullableDecl
                                    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)).

Throws:

NullPointerException - if input is null and this predicate does not accept null arguments

equals

boolean equals(@NullableDecl
               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.

Overrides:

equals in class Object

Parameters:

object - the reference object with which to compare.

Returns:

true if this object is the same as the obj argument; false otherwise.

See Also:

Object.hashCode(), HashMap

test

default boolean test(@NullableDecl
                     T input)

Description copied from interface: java.util.function.Predicate

Evaluates this predicate on the given argument.

Specified by:

test in interface Predicate<T>

Parameters:

input - the input argument

Returns:

true if the input argument matches the predicate, otherwise false