org.apache.commons.collections.functors
Class UniquePredicate

java.lang.Object
  org.apache.commons.collections.functors.UniquePredicate

All Implemented Interfaces:

java.io.Serializable, Predicate

public final class UniquePredicate
extends java.lang.Object
implements Predicate, java.io.Serializable

Predicate implementation that returns true the first time an object is passed into the predicate.

Since:

Commons Collections 3.0

Version:

$Revision: 646777 $ $Date: 2008-04-10 13:33:15 +0100 (Thu, 10 Apr 2008) $

Author:

Stephen Colebourne

See Also:

Serialized Form

Constructor Summary

UniquePredicate()
Constructor that performs no validation.

Method Summary

boolean	evaluate(java.lang.Object object) Evaluates the predicate returning true if the input object hasn't been received yet.
static Predicate	getInstance() Factory to create the predicate.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

UniquePredicate

public UniquePredicate()

Constructor that performs no validation. Use getInstance if you want that.

Method Detail

getInstance

public static Predicate getInstance()

Factory to create the predicate.

Returns:

the predicate

Throws:

java.lang.IllegalArgumentException - if the predicate is null

evaluate

public boolean evaluate(java.lang.Object object)

Evaluates the predicate returning true if the input object hasn't been received yet.

Specified by:

evaluate in interface Predicate

Parameters:

object - the input object

Returns:

true if this is the first time the object is seen