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 Detail

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:

java.lang.ClassCastException - (runtime) if the input is the wrong class

java.lang.IllegalArgumentException - (runtime) if the input is invalid

FunctorException - (runtime) if the predicate encounters a problem