org.apache.commons.collections4.functors
Class OnePredicate<T>

java.lang.Object
  org.apache.commons.collections4.functors.AbstractQuantifierPredicate<T>
      org.apache.commons.collections4.functors.OnePredicate<T>

All Implemented Interfaces:

Serializable, PredicateDecorator<T>, Predicate<T>

public final class OnePredicate<T>
extends AbstractQuantifierPredicate<T>
implements Serializable

Predicate implementation that returns true if only one of the predicates return true. If the array of predicates is empty, then this predicate returns false.

NOTE: In versions prior to 3.2 an array size of zero or one threw an exception.

Since:

3.0

Version:

$Id: OnePredicate.java 1479340 2013-05-05 15:37:41Z tn $

See Also:

Serialized Form

OnePredicate

public OnePredicate(Predicate<? super T>... predicates)

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

Parameters:

predicates - the predicates to check, not cloned, not null

onePredicate

public static <T> Predicate<T> onePredicate(Predicate<? super T>... predicates)

Factory to create the predicate.

If the array is size zero, the predicate always returns false. If the array is size one, then that predicate is returned.

Type Parameters:

T - the type that the predicate queries

Parameters:

predicates - the predicates to check, cloned, not null

Returns:

the any predicate

Throws:

IllegalArgumentException - if the predicates array is null

IllegalArgumentException - if any predicate in the array is null

onePredicate

public static <T> Predicate<T> onePredicate(Collection<? extends Predicate<T>> predicates)

Factory to create the predicate.

Type Parameters:

T - the type that the predicate queries

Parameters:

predicates - the predicates to check, cloned, not null

Returns:

the one predicate

Throws:

IllegalArgumentException - if the predicates array is null

IllegalArgumentException - if any predicate in the array is null

evaluate

public boolean evaluate(T object)

Evaluates the predicate returning true if only one decorated predicate returns true.

Specified by:

evaluate in interface Predicate<T>

Parameters:

object - the input object

Returns:

true if only one decorated predicate returns true