Package org.apache.commons.collections4.functors

Class UniquePredicate<T>

java.lang.Object

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

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

Type Parameters:

T - the type of the input to the predicate.

All Implemented Interfaces:

Serializable, Predicate<T>, Predicate<T>

public final class UniquePredicate<T>
extends AbstractPredicate<T>
implements 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	test(T object)	Evaluates the predicate returning true if the input object hasn't been received yet.
static <T> Predicate<T>	uniquePredicate()	Creates the predicate.

Methods inherited from class org.apache.commons.collections4.functors.AbstractPredicate

evaluate

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.util.function.Predicate

and, negate, or

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()

Creates the predicate.

Type Parameters:

T - the type that the predicate queries

Returns:

the predicate

Throws:

IllegalArgumentException - if the predicate is null

test

public boolean test(T object)

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

Specified by:

test in interface Predicate<T>

Specified by:

test in interface Predicate<T>

Parameters:

object - the input object

Returns:

true if this is the first time the object is seen