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 1999 (C) Intalio, Inc. All Rights Reserved.
32 *
33 * $Id$
34 */
35
36 package org.exolab.castor.mapping;
37
38 import java.util.Enumeration;
39
40 /**
41 * Collection handler for adding/listing elements of a collection. A collection field will use this
42 * handler to add elements when it's value is set, and to enumerate then when it's value is
43 * retrieved. A collection handler is instantiated only once, must be thread safe and not use any
44 * synchronization.
45 *
46 * @author <a href="arkin@intalio.com">Assaf Arkin</a>
47 * @version $Revision$ $Date: 2003-03-03 00:05:44 -0700 (Mon, 03 Mar 2003) $
48 */
49 public interface CollectionHandler<T> {
50
51 /**
52 * Add an object to the collection. A collection may not allow the same object to be added more
53 * than once. The collection is provided as a parameter and is returned as the return value if the
54 * returned collection is a different object. That way the handler can create a new collection or
55 * change the collection as necessary (e.g. when resizing an array).
56 *
57 * @param collection The collection, null if no collection has been created yet
58 * @param object The object to add to the collection
59 * @return The collection with the new object if a different instance than the <tt>collection</tt>
60 * parameter, null otherwise
61 * @throws ClassCastException The collection handler does not support collections of this type
62 */
63 public Object add(Object collection, T object) throws ClassCastException;
64
65 /**
66 * Returns an enumeration of all the elements in the collection.
67 *
68 * @param collection The collection
69 * @return An enumeration of all the elements in the collection
70 * @throws ClassCastException The collection handler does not support collections of this type
71 */
72 public Enumeration<T> elements(Object collection) throws ClassCastException;
73
74 /**
75 * Returns the number of elements in the collection.
76 *
77 * @param collection The collection
78 * @return Number of elements in the collection
79 * @throws ClassCastException The collection handler does not support collections of this type
80 */
81 public int size(Object collection) throws ClassCastException;
82
83 /**
84 * Clears the collection of any objects. The collection is provided as a parameter and is returned
85 * as the return value if the returned collection is a different object. That way the handler can
86 * create a new collection or change the collection as necessary (e.g. when resizing an array).
87 *
88 * @param collection The collection, null if no collection has been created yet
89 * @return The empty collection if a different instance than the <tt>collection</tt> parameter,
90 * null otherwise
91 * @throws ClassCastException The collection handler does not support collections of this type
92 */
93 public Object clear(Object collection) throws ClassCastException;
94
95 }