Interface Predicate<T extends @Nullable java.lang.Object>
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- All Known Implementing Classes:
BloomFilter,CharMatcher,Range
@GwtCompatible public interface Predicate<T extends @Nullable java.lang.Object>
Determines a true or false value for a given input; a pre-Java-8 version ofjava.util.function.Predicate.The
Predicatesclass provides common predicates and related utilities.See the Guava User Guide article on the use of
Predicate.For Java 8+ users
This interface is now a legacy type. Use
java.util.function.Predicate(or the appropriate primitive specialization such asIntPredicate) 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.To use a reference of this type (say, named
guavaPredicate) in a context wherejava.util.function.Predicateis expected, use the method referenceguavaPredicate::apply. For the other direction, usejavaUtilPredicate::test. A future version of this interface will be made to extendjava.util.function.Predicate, so that conversion will be necessary in only one direction. At that time, this interface will be officially discouraged.- Since:
- 2.0
- Author:
- Kevin Bourrillion
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Method Summary
All Methods Instance Methods Abstract Methods Modifier and Type Method Description booleanapply(T input)Returns the result of applying this predicate toinput(Java 8 users, see notes in the class documentation above).booleanequals(java.lang.Object object)Indicates whether another object is equal to this predicate.
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Method Detail
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apply
boolean apply(T input)
Returns the result of applying this predicate toinput(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 thatpredicate.apply(a) == predicate.apply(b)).
- Throws:
java.lang.NullPointerException- ifinputis null and this predicate does not accept null arguments
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equals
boolean equals(@CheckForNull java.lang.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 returntruewheneverobjectis aPredicatethat it considers interchangeable with this one. "Interchangeable" typically means thatthis.apply(t) == that.apply(t)for alltof typeT). Note that afalseresult from this method does not imply that the predicates are known not to be interchangeable.- Overrides:
equalsin classjava.lang.Object
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