/*
* Copyright 2001-2004,2006 The Apache Software Foundation
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.commons.collections.functors;
import java.io.Serializable;
import java.util.Collection;
import org.apache.commons.collections.Predicate;
/**
* 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.
* <p>
* NOTE: In versions prior to 3.2 an array size of zero or one
* threw an exception.
*
* @since Commons Collections 3.0
* @version $Revision: 406071 $ $Date: 2006-05-13 11:44:37 +0100 (Sat, 13 May 2006) $
*
* @author Stephen Colebourne
* @author Matt Benson
*/
public final class OnePredicate implements Predicate, PredicateDecorator, Serializable {
/** Serial version UID */
private static final long serialVersionUID = -8125389089924745785L;
/** The array of predicates to call */
private final Predicate[] iPredicates;
/**
* Factory to create the predicate.
* <p>
* If the array is size zero, the predicate always returns false.
* If the array is size one, then that predicate is returned.
*
* @param predicates the predicates to check, cloned, not null
* @return the <code>any</code> predicate
* @throws IllegalArgumentException if the predicates array is null
* @throws IllegalArgumentException if any predicate in the array is null
*/
public static Predicate getInstance(Predicate[] predicates) {
FunctorUtils.validate(predicates);
if (predicates.length == 0) {
return FalsePredicate.INSTANCE;
}
if (predicates.length == 1) {
return predicates[0];
}
predicates = FunctorUtils.copy(predicates);
return new OnePredicate(predicates);
}
/**
* Factory to create the predicate.
*
* @param predicates the predicates to check, cloned, not null
* @return the <code>one</code> predicate
* @throws IllegalArgumentException if the predicates array is null
* @throws IllegalArgumentException if any predicate in the array is null
*/
public static Predicate getInstance(Collection predicates) {
Predicate[] preds = FunctorUtils.validate(predicates);
return new OnePredicate(preds);
}
/**
* Constructor that performs no validation.
* Use <code>getInstance</code> if you want that.
*
* @param predicates the predicates to check, not cloned, not null
*/
public OnePredicate(Predicate[] predicates) {
super();
iPredicates = predicates;
}
/**
* Evaluates the predicate returning true if only one decorated predicate
* returns true.
*
* @param object the input object
* @return true if only one decorated predicate returns true
*/
public boolean evaluate(Object object) {
boolean match = false;
for (int i = 0; i < iPredicates.length; i++) {
if (iPredicates[i].evaluate(object)) {
if (match) {
return false;
}
match = true;
}
}
return match;
}
/**
* Gets the predicates, do not modify the array.
*
* @return the predicates
* @since Commons Collections 3.1
*/
public Predicate[] getPredicates() {
return iPredicates;
}
}