org.apache.commons.collections.functors.TransformedPredicate Maven / Gradle / Ivy
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* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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.Predicate;
import org.apache.commons.collections.Transformer;
/**
* Predicate implementation that transforms the given object before invoking
* another Predicate.
*
* @since Commons Collections 3.1
* @version $Revision: 646777 $ $Date: 2008-04-10 13:33:15 +0100 (Thu, 10 Apr 2008) $
* @author Alban Peignier
* @author Stephen Colebourne
*/
public final class TransformedPredicate implements Predicate, PredicateDecorator, Serializable {
/** Serial version UID */
private static final long serialVersionUID = -5596090919668315834L;
/** The transformer to call */
private final Transformer iTransformer;
/** The predicate to call */
private final Predicate iPredicate;
/**
* Factory to create the predicate.
*
* @param transformer the transformer to call
* @param predicate the predicate to call with the result of the transform
* @return the predicate
* @throws IllegalArgumentException if the transformer or the predicate is null
*/
public static Predicate getInstance(Transformer transformer, Predicate predicate) {
if (transformer == null) {
throw new IllegalArgumentException("The transformer to call must not be null");
}
if (predicate == null) {
throw new IllegalArgumentException("The predicate to call must not be null");
}
return new TransformedPredicate(transformer, predicate);
}
/**
* Constructor that performs no validation.
* Use getInstance if you want that.
*
* @param transformer the transformer to use
* @param predicate the predicate to decorate
*/
public TransformedPredicate(Transformer transformer, Predicate predicate) {
iTransformer = transformer;
iPredicate = predicate;
}
/**
* Evaluates the predicate returning the result of the decorated predicate
* once the input has been transformed
*
* @param object the input object which will be transformed
* @return true if decorated predicate returns true
*/
public boolean evaluate(Object object) {
Object result = iTransformer.transform(object);
return iPredicate.evaluate(result);
}
/**
* 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};
}
/**
* Gets the transformer in use.
*
* @return the transformer
*/
public Transformer getTransformer() {
return iTransformer;
}
}