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.Factory; 022 import org.apache.commons.collections.Transformer; 023 024 /** 025 * Transformer implementation that calls a Factory and returns the result. 026 * 027 * @since Commons Collections 3.0 028 * @version $Revision: 646777 $ $Date: 2008-04-10 13:33:15 +0100 (Thu, 10 Apr 2008) $ 029 * 030 * @author Stephen Colebourne 031 */ 032 public class FactoryTransformer implements Transformer, Serializable { 033 034 /** Serial version UID */ 035 private static final long serialVersionUID = -6817674502475353160L; 036 037 /** The factory to wrap */ 038 private final Factory iFactory; 039 040 /** 041 * Factory method that performs validation. 042 * 043 * @param factory the factory to call, not null 044 * @return the <code>factory</code> transformer 045 * @throws IllegalArgumentException if the factory is null 046 */ 047 public static Transformer getInstance(Factory factory) { 048 if (factory == null) { 049 throw new IllegalArgumentException("Factory must not be null"); 050 } 051 return new FactoryTransformer(factory); 052 } 053 054 /** 055 * Constructor that performs no validation. 056 * Use <code>getInstance</code> if you want that. 057 * 058 * @param factory the factory to call, not null 059 */ 060 public FactoryTransformer(Factory factory) { 061 super(); 062 iFactory = factory; 063 } 064 065 /** 066 * Transforms the input by ignoring the input and returning the result of 067 * calling the decorated factory. 068 * 069 * @param input the input object to transform 070 * @return the transformed result 071 */ 072 public Object transform(Object input) { 073 return iFactory.create(); 074 } 075 076 /** 077 * Gets the factory. 078 * 079 * @return the factory 080 * @since Commons Collections 3.1 081 */ 082 public Factory getFactory() { 083 return iFactory; 084 } 085 086 }