| /* |
| * 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; |
| import org.apache.commons.collections.Transformer; |
| |
| /** |
| * Predicate implementation that returns the result of a transformer. |
| * |
| * @since Commons Collections 3.0 |
| * @version $Revision: 1.1 $ $Date: 2009/05/27 22:16:33 $ |
| * |
| * @author Stephen Colebourne |
| */ |
| public final class TransformerPredicate implements Predicate, Serializable { |
| |
| /** Serial version UID */ |
| private static final long serialVersionUID = -2407966402920578741L; |
| |
| /** The transformer to call */ |
| private final Transformer iTransformer; |
| |
| /** |
| * Factory to create the predicate. |
| * |
| * @param transformer the transformer to decorate |
| * @return the predicate |
| * @throws IllegalArgumentException if the transformer is null |
| */ |
| public static Predicate getInstance(Transformer transformer) { |
| if (transformer == null) { |
| throw new IllegalArgumentException("The transformer to call must not be null"); |
| } |
| return new TransformerPredicate(transformer); |
| } |
| |
| /** |
| * Constructor that performs no validation. |
| * Use <code>getInstance</code> if you want that. |
| * |
| * @param transformer the transformer to decorate |
| */ |
| public TransformerPredicate(Transformer transformer) { |
| super(); |
| iTransformer = transformer; |
| } |
| |
| /** |
| * Evaluates the predicate returning the result of the decorated transformer. |
| * |
| * @param object the input object |
| * @return true if decorated transformer returns Boolean.TRUE |
| * @throws FunctorException if the transformer returns an invalid type |
| */ |
| public boolean evaluate(Object object) { |
| Object result = iTransformer.transform(object); |
| if (result instanceof Boolean == false) { |
| throw new FunctorException( |
| "Transformer must return an instanceof Boolean, it was a " |
| + (result == null ? "null object" : result.getClass().getName())); |
| } |
| return ((Boolean) result).booleanValue(); |
| } |
| |
| /** |
| * Gets the transformer. |
| * |
| * @return the transformer |
| * @since Commons Collections 3.1 |
| */ |
| public Transformer getTransformer() { |
| return iTransformer; |
| } |
| |
| } |