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.bag; 018 019 import java.util.Set; 020 021 import org.apache.commons.collections.Bag; 022 import org.apache.commons.collections.Transformer; 023 import org.apache.commons.collections.collection.TransformedCollection; 024 import org.apache.commons.collections.set.TransformedSet; 025 026 /** 027 * Decorates another <code>Bag</code> to transform objects that are added. 028 * <p> 029 * The add methods are affected by this class. 030 * Thus objects must be removed or searched for using their transformed form. 031 * For example, if the transformation converts Strings to Integers, you must 032 * use the Integer form to remove objects. 033 * <p> 034 * This class is Serializable from Commons Collections 3.1. 035 * 036 * @since Commons Collections 3.0 037 * @version $Revision: 646777 $ $Date: 2008-04-10 13:33:15 +0100 (Thu, 10 Apr 2008) $ 038 * 039 * @author Stephen Colebourne 040 */ 041 public class TransformedBag 042 extends TransformedCollection implements Bag { 043 044 /** Serialization version */ 045 private static final long serialVersionUID = 5421170911299074185L; 046 047 /** 048 * Factory method to create a transforming bag. 049 * <p> 050 * If there are any elements already in the bag being decorated, they 051 * are NOT transformed. 052 * 053 * @param bag the bag to decorate, must not be null 054 * @param transformer the transformer to use for conversion, must not be null 055 * @return a new transformed Bag 056 * @throws IllegalArgumentException if bag or transformer is null 057 */ 058 public static Bag decorate(Bag bag, Transformer transformer) { 059 return new TransformedBag(bag, transformer); 060 } 061 062 //----------------------------------------------------------------------- 063 /** 064 * Constructor that wraps (not copies). 065 * <p> 066 * If there are any elements already in the bag being decorated, they 067 * are NOT transformed. 068 * 069 * @param bag the bag to decorate, must not be null 070 * @param transformer the transformer to use for conversion, must not be null 071 * @throws IllegalArgumentException if bag or transformer is null 072 */ 073 protected TransformedBag(Bag bag, Transformer transformer) { 074 super(bag, transformer); 075 } 076 077 /** 078 * Gets the decorated bag. 079 * 080 * @return the decorated bag 081 */ 082 protected Bag getBag() { 083 return (Bag) collection; 084 } 085 086 //----------------------------------------------------------------------- 087 public int getCount(Object object) { 088 return getBag().getCount(object); 089 } 090 091 public boolean remove(Object object, int nCopies) { 092 return getBag().remove(object, nCopies); 093 } 094 095 //----------------------------------------------------------------------- 096 public boolean add(Object object, int nCopies) { 097 object = transform(object); 098 return getBag().add(object, nCopies); 099 } 100 101 public Set uniqueSet() { 102 Set set = getBag().uniqueSet(); 103 return TransformedSet.decorate(set, transformer); 104 } 105 106 }