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 1999-2000 (C) Intalio, Inc. All Rights Reserved.
42 *
43 */
44
45 package org.exolab.castor.xml.schema;
46
47 /**
48 * Defines an object resolver but does not specify any implementation.
49 * <p>
50 * A lazy resolver would resolve an object given its identifier.
51 * The reference to the object will be created with a {@link
52 * ResolvableReference} object using the resolved and the identifier.
53 * When the object is requested, the {@link #resolve} method will be
54 * called to obtain it.
55 * <p>
56 * Some implementation will add and remove resolvable objects, e.g.
57 * a collection of objects that also acts as a resolver. These methods
58 * should implement {@link #addResolvable} and {@link #removeResolvable}.
59 * Resolvers that do not implement these methods are still considered
60 * valid resolvers. For example, a database based resolver will operate
61 * consistently without implementing add/remove not through the database
62 * interface.
63 *
64 * @author <a href="arkin@intalio.com">Assaf Arkin</a>
65 * @see ResolvableReference
66 **/
67 public interface Resolver
68 {
69
70
71 /**
72 * Called to resolve a reference give the reference's identifier.
73 * If the reference is known, this method should return the referenced
74 * object. If the reference is unknown, this method should return
75 * null.
76 *
77 * @param id The identifier to resolve
78 * @return The resolved object
79 **/
80 public Referable resolve( String id );
81
82
83 /**
84 * Adds a resolvable object to this resolver identified by <tt>id</tt>.
85 * Subsequent calls to {@link #resolve} with the same <tt>id</tt>
86 * will return <tt>referent</tt>.
87 *
88 * @param id The referent's identifier
89 * @param referent The referent object
90 */
91 public void addResolvable( String id, Referable referent );
92
93
94 /**
95 * Removes a resolvable object from this resolver. Subsequent calls
96 * to {@link #resolve} with the same <tt>id</tt> will return null.
97 *
98 * @param id The referent's identifier
99 */
100 public void removeResolvable( String id );
101
102
103 }
104