001 /*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements. See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License. You may obtain a copy of the License at
008 *
009 * http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017 package org.apache.commons.collections.functors;
018
019 import java.io.Serializable;
020
021 import org.apache.commons.collections.Closure;
022 import org.apache.commons.collections.Transformer;
023
024 /**
025 * Closure implementation that calls a Transformer using the input object
026 * and ignore the result.
027 *
028 * @since Commons Collections 3.0
029 * @version $Revision: 646777 $ $Date: 2008-04-10 13:33:15 +0100 (Thu, 10 Apr 2008) $
030 *
031 * @author Stephen Colebourne
032 */
033 public class TransformerClosure implements Closure, Serializable {
034
035 /** Serial version UID */
036 private static final long serialVersionUID = -5194992589193388969L;
037
038 /** The transformer to wrap */
039 private final Transformer iTransformer;
040
041 /**
042 * Factory method that performs validation.
043 * <p>
044 * A null transformer will return the <code>NOPClosure</code>.
045 *
046 * @param transformer the transformer to call, null means nop
047 * @return the <code>transformer</code> closure
048 */
049 public static Closure getInstance(Transformer transformer) {
050 if (transformer == null) {
051 return NOPClosure.INSTANCE;
052 }
053 return new TransformerClosure(transformer);
054 }
055
056 /**
057 * Constructor that performs no validation.
058 * Use <code>getInstance</code> if you want that.
059 *
060 * @param transformer the transformer to call, not null
061 */
062 public TransformerClosure(Transformer transformer) {
063 super();
064 iTransformer = transformer;
065 }
066
067 /**
068 * Executes the closure by calling the decorated transformer.
069 *
070 * @param input the input object
071 */
072 public void execute(Object input) {
073 iTransformer.transform(input);
074 }
075
076 /**
077 * Gets the transformer.
078 *
079 * @return the transformer
080 * @since Commons Collections 3.1
081 */
082 public Transformer getTransformer() {
083 return iTransformer;
084 }
085
086 }