Module org.apache.commons.collections4
Package org.apache.commons.collections4

Interface Predicate<T>

Type Parameters:
T - the type that the predicate queries
All Known Subinterfaces:
PredicateDecorator<T>
All Known Implementing Classes:
AbstractQuantifierPredicate, AllPredicate, AndPredicate, AnyPredicate, ComparatorPredicate, EqualPredicate, ExceptionPredicate, FalsePredicate, IdentityPredicate, InstanceofPredicate, NonePredicate, NotNullPredicate, NotPredicate, NullIsExceptionPredicate, NullIsFalsePredicate, NullIsTruePredicate, NullPredicate, OnePredicate, OrPredicate, TransformedPredicate, TransformerPredicate, TruePredicate, UniquePredicate
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>
Defines a functor interface implemented by classes that perform a predicate test on an object.

A Predicate is the object equivalent of an if statement. It uses the input object to return a true or false value, and is often used in validation or filtering.

Standard implementations of common predicates are provided by PredicateUtils. These include true, false, instanceof, equals, and, or, not, method invokation and null testing.

Since:
1.0

  • Method Summary

    Modifier and Type
    Method
    Description
    boolean
    evaluate(T object)
    Use the specified parameter to perform a test that returns true or false.

  • Method Details

    • evaluate

      boolean evaluate(T object)
      Use the specified parameter to perform a test that returns true or false.
      Parameters:
      object - the object to evaluate, should not be changed
      Returns:
      true or false
      Throws:
      ClassCastException - (runtime) if the input is the wrong class
      IllegalArgumentException - (runtime) if the input is invalid
      FunctorException - (runtime) if the predicate encounters a problem