1 /**
2 * Redistribution and use of this software and associated documentation
3 * ("Software"), with or without modification, are permitted provided
4 * that the following conditions are met:
5 *
6 * 1. Redistributions of source code must retain copyright
7 * statements and notices. Redistributions must also contain a
8 * copy of this document.
9 *
10 * 2. Redistributions in binary form must reproduce the
11 * above copyright notice, this list of conditions and the
12 * following disclaimer in the documentation and/or other
13 * materials provided with the distribution.
14 *
15 * 3. The name "Exolab" must not be used to endorse or promote
16 * products derived from this Software without prior written
17 * permission of Intalio, Inc. For written permission,
18 * please contact info@exolab.org.
19 *
20 * 4. Products derived from this Software may not be called "Exolab"
21 * nor may "Exolab" appear in their names without prior written
22 * permission of Intalio, Inc. Exolab is a registered
23 * trademark of Intalio, Inc.
24 *
25 * 5. Due credit should be given to the Exolab Project
26 * (http://www.exolab.org/).
27 *
28 * THIS SOFTWARE IS PROVIDED BY INTALIO, INC. AND CONTRIBUTORS
29 * ``AS IS'' AND ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT
30 * NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
31 * FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
32 * INTALIO, INC. OR ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
33 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
34 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
35 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
36 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
37 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
38 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
39 * OF THE POSSIBILITY OF SUCH DAMAGE.
40 *
41 * Copyright 2002 (C) Intalio, Inc. All Rights Reserved.
42 *
43 * $Id$
44 */
45
46
47 package org.exolab.castor.mapping.handlers;
48
49 import org.exolab.castor.mapping.MapHandler;
50 import java.util.Enumeration;
51 import java.util.Hashtable;
52
53 /**
54 * A Map handler for adding and retreiving key-value pairs from
55 * A map. A map handler is instantiated only once, must be thread
56 * safe and not use any synchronization.
57 *
58 * @author <a href="mailto:kvisco@intalio.com">Keith Visco</a>
59 * @version $Revision$ $Date: 2003-03-03 00:05:44 -0700 (Mon, 03 Mar 2003) $
60 */
61 public final class J1MapHandler
62 implements MapHandler
63 {
64
65 /**
66 * Creates a new Instance of the map represented by this MapHandler.
67 *
68 * @return the new map.
69 */
70 public Object create() {
71 return new Hashtable();
72 } //-- create
73
74 /**
75 * Adds the given key-value pair to the map. Keys must be unique.
76 * Adding a key-value pair to the map, when an existing association
77 * for that key already exists will cause the existing association
78 * to be overwritten.
79 *
80 * The map is provided as a parameter and is returned as the return
81 * value if the returned map is a different object. That way the handler
82 * can create a new map if necessary.
83 *
84 * @param map the map, null if no map has been created yet.
85 * @param key the key for the object.
86 * @param object the object to add to the map.
87 * @return The map with the new object if a different
88 * instance than the <tt>map</tt> parameter, null otherwise
89 * @throws ClassCastException The MapHandler does not
90 * support maps of the given type.
91 */
92 public Object put( Object map, Object key, Object object )
93 throws ClassCastException
94 {
95 Object returnVal = null;
96 if (map == null) {
97 map = new Hashtable();
98 returnVal = map;
99 }
100 ((Hashtable)map).put(key, object);
101 return returnVal;
102 } //-- put
103
104
105 /**
106 * Returns an enumeration of all the objects in the Map.
107 *
108 * @param map The map instance for which to return the enumeration
109 * of elements for.
110 * @return An enumeration of all the elements in the Map.
111 * @throws ClassCastException The MapHandler does not
112 * support collections of this type
113 */
114 public Enumeration elements( Object map )
115 throws ClassCastException
116 {
117 if (map == null) map = new Hashtable();
118 return ((Hashtable)map).elements();
119 } //-- elements
120
121 /**
122 * Returns an enumeration of all the keys in the Map.
123 *
124 * @param map The map instance for which to return the enumeration
125 * of keys.
126 * @return An enumeration of all the keys in the Map.
127 * @throws ClassCastException The MapHandler does not
128 * support collections of this type
129 */
130 public Enumeration keys( Object map )
131 throws ClassCastException
132 {
133 if (map == null) map = new Hashtable();
134 return ((Hashtable)map).keys();
135 } //-- keys
136
137
138 /**
139 * Returns the number of elements (key-value) in the map.
140 *
141 * @param map the map.
142 * @return Number of key-value associations in the Map
143 * @throws ClassCastException The MapHandler does not
144 * support collections of the given type.
145 */
146 public int size( Object map )
147 throws ClassCastException
148 {
149 if (map == null) return 0;
150 return ((Hashtable)map).size();
151 } //-- size
152
153
154 /**
155 * Clears the map of all key-value pairs.
156 *
157 * @param map the map to clear.
158 * @throws ClassCastException The MapHandler does not
159 * support collections of the given type.
160 */
161 public void clear( Object map)
162 throws ClassCastException
163 {
164 if (map == null) return;
165 ((Hashtable)map).clear();
166 } //-- clear
167
168 /**
169 * Returns the object associated with the given key.
170 *
171 * @param map the map to return the object from.
172 * @param key the key for the object.
173 * @return the object associated with the given key, or null
174 * if no association was found in the given map.
175 * @throws ClassCastException The MapHandler does not
176 * support maps of the given type.
177 */
178 public Object get( Object map, Object key)
179 throws ClassCastException
180 {
181 if (map == null) return null;
182 return ((Hashtable)map).get(key);
183 } //-- get
184
185 } //-- J1MapHandler
186
187
188