1 /** 2 * Redistribution and use of this software and associated documentation ("Software"), with or 3 * without modification, are permitted provided that the following conditions are met: 4 * 5 * 1. Redistributions of source code must retain copyright statements and notices. Redistributions 6 * must also contain a copy of this document. 7 * 8 * 2. Redistributions in binary form must reproduce the above copyright notice, this list of 9 * conditions and the following disclaimer in the documentation and/or other materials provided with 10 * the distribution. 11 * 12 * 3. The name "Exolab" must not be used to endorse or promote products derived from this Software 13 * without prior written permission of Intalio, Inc. For written permission, please contact 14 * info@exolab.org. 15 * 16 * 4. Products derived from this Software may not be called "Exolab" nor may "Exolab" appear in 17 * their names without prior written permission of Intalio, Inc. Exolab is a registered trademark of 18 * Intalio, Inc. 19 * 20 * 5. Due credit should be given to the Exolab Project (http://www.exolab.org/). 21 * 22 * THIS SOFTWARE IS PROVIDED BY INTALIO, INC. AND CONTRIBUTORS ``AS IS'' AND ANY EXPRESSED OR 23 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND 24 * FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL INTALIO, INC. OR ITS 25 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 27 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 28 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY 29 * WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 30 * 31 * Copyright 2002 (C) Intalio, Inc. All Rights Reserved. 32 * 33 * $Id$ 34 */ 35 36 37 package org.exolab.castor.mapping.handlers; 38 39 import org.exolab.castor.mapping.MapHandler; 40 import java.util.Enumeration; 41 import java.util.HashMap; 42 import java.util.Map; 43 import java.util.Iterator; 44 45 /** 46 * A Map handler for adding and retreiving key-value pairs from A map. A map handler is instantiated 47 * only once, must be thread safe and not use any synchronization. 48 * 49 * @author <a href="mailto:kvisco@intalio.com">Keith Visco</a> 50 * @version $Revision$ $Date: 2003-03-03 00:05:44 -0700 (Mon, 03 Mar 2003) $ 51 */ 52 public final class J2MapHandler implements MapHandler { 53 54 /** 55 * Creates a new Instance of the map represented by this MapHandler. 56 * 57 * @return the new map. 58 */ 59 public Object create() { 60 return new HashMap(); 61 } // -- create 62 63 /** 64 * Adds the given key-value pair to the map. Keys must be unique. Adding a key-value pair to the 65 * map, when an existing association for that key already exists will cause the existing 66 * association to be overwritten. 67 * 68 * The map is provided as a parameter and is returned as the return value if the returned map is a 69 * different object. That way the handler can create a new map if necessary. 70 * 71 * @param map the map, null if no map has been created yet. 72 * @param key the key for the object. 73 * @param object the object to add to the map. 74 * @return The map with the new object if a different instance than the <tt>map</tt> parameter, 75 * null otherwise 76 * @throws ClassCastException The MapHandler does not support maps of the given type. 77 */ 78 public Object put(Object map, Object key, Object object) throws ClassCastException { 79 Object returnVal = null; 80 if (map == null) { 81 map = create(); 82 returnVal = map; 83 } 84 ((Map) map).put(key, object); 85 return returnVal; 86 } // -- put 87 88 89 /** 90 * Returns an enumeration of all the objects in the Map. 91 * 92 * @param map The map instance for which to return the enumeration of elements for. 93 * @return An enumeration of all the elements in the Map. 94 * @throws ClassCastException The MapHandler does not support collections of this type 95 */ 96 public Enumeration elements(Object map) throws ClassCastException { 97 if (map == null) 98 map = create(); 99 return new IteratorEnumerator(((Map) map).values().iterator()); 100 } // -- elements 101 102 /** 103 * Returns an enumeration of all the keys in the Map. 104 * 105 * @param map The map instance for which to return the enumeration of keys. 106 * @return An enumeration of all the keys in the Map. 107 * @throws ClassCastException The MapHandler does not support collections of this type 108 */ 109 public Enumeration keys(Object map) throws ClassCastException { 110 if (map == null) 111 map = create(); 112 return new IteratorEnumerator(((Map) map).keySet().iterator()); 113 } // -- keys 114 115 116 /** 117 * Returns the number of elements (key-value) in the map. 118 * 119 * @param map the map. 120 * @return Number of key-value associations in the Map 121 * @throws ClassCastException The MapHandler does not support collections of the given type. 122 */ 123 public int size(Object map) throws ClassCastException { 124 if (map == null) 125 return 0; 126 return ((Map) map).size(); 127 } // -- size 128 129 130 /** 131 * Clears the map of all key-value pairs. 132 * 133 * @param map the map to clear. 134 * @throws ClassCastException The MapHandler does not support collections of the given type. 135 */ 136 public void clear(Object map) throws ClassCastException { 137 if (map == null) 138 return; 139 ((Map) map).clear(); 140 } // -- clear 141 142 /** 143 * Returns the object associated with the given key. 144 * 145 * @param map the map to return the object from. 146 * @param key the key for the object. 147 * @return the object associated with the given key, or null if no association was found in the 148 * given map. 149 * @throws ClassCastException The MapHandler does not support maps of the given type. 150 */ 151 public Object get(Object map, Object key) throws ClassCastException { 152 if (map == null) 153 return null; 154 return ((Map) map).get(key); 155 } // -- get 156 157 /** 158 * Enumerator for an iterator. 159 */ 160 static final class IteratorEnumerator implements Enumeration { 161 162 private final Iterator _iterator; 163 164 IteratorEnumerator(Iterator iterator) { 165 _iterator = iterator; 166 } 167 168 public boolean hasMoreElements() { 169 return _iterator.hasNext(); 170 } 171 172 public Object nextElement() { 173 return _iterator.next(); 174 } 175 176 } 177 178 } // -- J2MapHandler 179 180