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 1999-2000 (C) Intalio, Inc. All Rights Reserved.
32 *
33 */
34
35 package org.exolab.castor.xml.schema;
36
37 /**
38 * Defines an object resolver but does not specify any implementation.
39 * <p>
40 * A lazy resolver would resolve an object given its identifier. The reference to the object will be
41 * created with a {@link ResolvableReference} object using the resolved and the identifier. When the
42 * object is requested, the {@link #resolve} method will be called to obtain it.
43 * <p>
44 * Some implementation will add and remove resolvable objects, e.g. a collection of objects that
45 * also acts as a resolver. These methods should implement {@link #addResolvable} and
46 * {@link #removeResolvable}. Resolvers that do not implement these methods are still considered
47 * valid resolvers. For example, a database based resolver will operate consistently without
48 * implementing add/remove not through the database interface.
49 *
50 * @author <a href="arkin@intalio.com">Assaf Arkin</a>
51 * @see ResolvableReference
52 **/
53 public interface Resolver {
54
55
56 /**
57 * Called to resolve a reference give the reference's identifier. If the reference is known, this
58 * method should return the referenced object. If the reference is unknown, this method should
59 * return null.
60 *
61 * @param id The identifier to resolve
62 * @return The resolved object
63 **/
64 public Referable resolve(String id);
65
66
67 /**
68 * Adds a resolvable object to this resolver identified by <tt>id</tt>. Subsequent calls to
69 * {@link #resolve} with the same <tt>id</tt> will return <tt>referent</tt>.
70 *
71 * @param id The referent's identifier
72 * @param referent The referent object
73 */
74 public void addResolvable(String id, Referable referent);
75
76
77 /**
78 * Removes a resolvable object from this resolver. Subsequent calls to {@link #resolve} with the
79 * same <tt>id</tt> will return null.
80 *
81 * @param id The referent's identifier
82 */
83 public void removeResolvable(String id);
84
85
86 }
87