/*
* Copyright 2001-2004 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 org.apache.commons.collections.FunctorException;
import org.apache.commons.collections.Predicate;
/**
* Predicate implementation that throws an exception if the input is null.
*
* @since Commons Collections 3.0
* @version $Revision: 1.7 $ $Date: 2004/05/31 16:43:17 $
*
* @author Stephen Colebourne
*/
public final class NullIsExceptionPredicate implements Predicate, PredicateDecorator, Serializable {
/** Serial version UID */
static final long serialVersionUID = 3243449850504576071L;
/** The predicate to decorate */
private final Predicate iPredicate;
/**
* Factory to create the null exception predicate.
*
* @param predicate the predicate to decorate, not null
* @return the predicate
* @throws IllegalArgumentException if the predicate is null
*/
public static Predicate getInstance(Predicate predicate) {
if (predicate == null) {
throw new IllegalArgumentException("Predicate must not be null");
}
return new NullIsExceptionPredicate(predicate);
}
/**
* Constructor that performs no validation.
* Use <code>getInstance</code> if you want that.
*
* @param predicate the predicate to call after the null check
*/
public NullIsExceptionPredicate(Predicate predicate) {
super();
iPredicate = predicate;
}
/**
* Evaluates the predicate returning the result of the decorated predicate
* once a null check is performed.
*
* @param object the input object
* @return true if decorated predicate returns true
* @throws FunctorException if input is null
*/
public boolean evaluate(Object object) {
if (object == null) {
throw new FunctorException("Input Object must not be null");
}
return iPredicate.evaluate(object);
}
/**
* Gets the predicate being decorated.
*
* @return the predicate as the only element in an array
* @since Commons Collections 3.1
*/
public Predicate[] getPredicates() {
return new Predicate[] {iPredicate};
}
}