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.map; 018 019 import java.io.IOException; 020 import java.io.ObjectInputStream; 021 import java.io.ObjectOutputStream; 022 import java.io.Serializable; 023 import java.util.Iterator; 024 import java.util.Map; 025 026 import org.apache.commons.collections.Predicate; 027 028 /** 029 * Decorates another <code>Map</code> to validate that additions 030 * match a specified predicate. 031 * <p> 032 * This map exists to provide validation for the decorated map. 033 * It is normally created to decorate an empty map. 034 * If an object cannot be added to the map, an IllegalArgumentException is thrown. 035 * <p> 036 * One usage would be to ensure that no null keys are added to the map. 037 * <pre>Map map = PredicatedSet.decorate(new HashMap(), NotNullPredicate.INSTANCE, null);</pre> 038 * <p> 039 * <strong>Note that PredicatedMap is not synchronized and is not thread-safe.</strong> 040 * If you wish to use this map from multiple threads concurrently, you must use 041 * appropriate synchronization. The simplest approach is to wrap this map 042 * using {@link java.util.Collections#synchronizedMap(Map)}. This class may throw 043 * exceptions when accessed by concurrent threads without synchronization. 044 * <p> 045 * This class is Serializable from Commons Collections 3.1. 046 * 047 * @since Commons Collections 3.0 048 * @version $Revision: 646777 $ $Date: 2008-04-10 13:33:15 +0100 (Thu, 10 Apr 2008) $ 049 * 050 * @author Stephen Colebourne 051 * @author Paul Jack 052 */ 053 public class PredicatedMap 054 extends AbstractInputCheckedMapDecorator 055 implements Serializable { 056 057 /** Serialization version */ 058 private static final long serialVersionUID = 7412622456128415156L; 059 060 /** The key predicate to use */ 061 protected final Predicate keyPredicate; 062 /** The value predicate to use */ 063 protected final Predicate valuePredicate; 064 065 /** 066 * Factory method to create a predicated (validating) map. 067 * <p> 068 * If there are any elements already in the list being decorated, they 069 * are validated. 070 * 071 * @param map the map to decorate, must not be null 072 * @param keyPredicate the predicate to validate the keys, null means no check 073 * @param valuePredicate the predicate to validate to values, null means no check 074 * @throws IllegalArgumentException if the map is null 075 */ 076 public static Map decorate(Map map, Predicate keyPredicate, Predicate valuePredicate) { 077 return new PredicatedMap(map, keyPredicate, valuePredicate); 078 } 079 080 //----------------------------------------------------------------------- 081 /** 082 * Constructor that wraps (not copies). 083 * 084 * @param map the map to decorate, must not be null 085 * @param keyPredicate the predicate to validate the keys, null means no check 086 * @param valuePredicate the predicate to validate to values, null means no check 087 * @throws IllegalArgumentException if the map is null 088 */ 089 protected PredicatedMap(Map map, Predicate keyPredicate, Predicate valuePredicate) { 090 super(map); 091 this.keyPredicate = keyPredicate; 092 this.valuePredicate = valuePredicate; 093 094 Iterator it = map.entrySet().iterator(); 095 while (it.hasNext()) { 096 Map.Entry entry = (Map.Entry) it.next(); 097 Object key = entry.getKey(); 098 Object value = entry.getValue(); 099 validate(key, value); 100 } 101 } 102 103 //----------------------------------------------------------------------- 104 /** 105 * Write the map out using a custom routine. 106 * 107 * @param out the output stream 108 * @throws IOException 109 * @since Commons Collections 3.1 110 */ 111 private void writeObject(ObjectOutputStream out) throws IOException { 112 out.defaultWriteObject(); 113 out.writeObject(map); 114 } 115 116 /** 117 * Read the map in using a custom routine. 118 * 119 * @param in the input stream 120 * @throws IOException 121 * @throws ClassNotFoundException 122 * @since Commons Collections 3.1 123 */ 124 private void readObject(ObjectInputStream in) throws IOException, ClassNotFoundException { 125 in.defaultReadObject(); 126 map = (Map) in.readObject(); 127 } 128 129 //----------------------------------------------------------------------- 130 /** 131 * Validates a key value pair. 132 * 133 * @param key the key to validate 134 * @param value the value to validate 135 * @throws IllegalArgumentException if invalid 136 */ 137 protected void validate(Object key, Object value) { 138 if (keyPredicate != null && keyPredicate.evaluate(key) == false) { 139 throw new IllegalArgumentException("Cannot add key - Predicate rejected it"); 140 } 141 if (valuePredicate != null && valuePredicate.evaluate(value) == false) { 142 throw new IllegalArgumentException("Cannot add value - Predicate rejected it"); 143 } 144 } 145 146 /** 147 * Override to validate an object set into the map via <code>setValue</code>. 148 * 149 * @param value the value to validate 150 * @throws IllegalArgumentException if invalid 151 * @since Commons Collections 3.1 152 */ 153 protected Object checkSetValue(Object value) { 154 if (valuePredicate.evaluate(value) == false) { 155 throw new IllegalArgumentException("Cannot set value - Predicate rejected it"); 156 } 157 return value; 158 } 159 160 /** 161 * Override to only return true when there is a value transformer. 162 * 163 * @return true if a value predicate is in use 164 * @since Commons Collections 3.1 165 */ 166 protected boolean isSetValueChecking() { 167 return (valuePredicate != null); 168 } 169 170 //----------------------------------------------------------------------- 171 public Object put(Object key, Object value) { 172 validate(key, value); 173 return map.put(key, value); 174 } 175 176 public void putAll(Map mapToCopy) { 177 Iterator it = mapToCopy.entrySet().iterator(); 178 while (it.hasNext()) { 179 Map.Entry entry = (Map.Entry) it.next(); 180 Object key = entry.getKey(); 181 Object value = entry.getValue(); 182 validate(key, value); 183 } 184 map.putAll(mapToCopy); 185 } 186 187 }