Package org.apache.commons.collections4.functors

Class UniquePredicate<T>

java.lang.Object

org.apache.commons.collections4.functors.UniquePredicate<T>

All Implemented Interfaces:

Serializable, Predicate<T>

public final class UniquePredicate<T>
extends Object
implements Predicate<T>, Serializable

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

Since:

3.0

See Also:

• Serialized Form

Constructor Summary

Constructors

Constructor	Description
UniquePredicate()	Constructor that performs no validation.

Method Summary

Modifier and Type	Method	Description
boolean	evaluate(T object)	Evaluates the predicate returning true if the input object hasn't been received yet.
static <T> Predicate<T>	uniquePredicate()	Factory to create the predicate.

Methods inherited from class java.lang.Object

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

Constructor Details

UniquePredicate

public UniquePredicate()

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

Method Details

uniquePredicate

public static <T> Predicate<T> uniquePredicate()

Factory to create the predicate.

Type Parameters:

T - the type that the predicate queries

Returns:

the predicate

Throws:

IllegalArgumentException - if the predicate is null

evaluate

public boolean evaluate(T object)

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

Specified by:

evaluate in interface Predicate<T>

Parameters:

object - the input object

Returns:

true if this is the first time the object is seen