01: /* Copyright 2004, 2005, 2006 Acegi Technology Pty Limited
02: *
03: * Licensed under the Apache License, Version 2.0 (the "License");
04: * you may not use this file except in compliance with the License.
05: * You may obtain a copy of the License at
06: *
07: * http://www.apache.org/licenses/LICENSE-2.0
08: *
09: * Unless required by applicable law or agreed to in writing, software
10: * distributed under the License is distributed on an "AS IS" BASIS,
11: * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12: * See the License for the specific language governing permissions and
13: * limitations under the License.
14: */
15:
16: package org.acegisecurity.acl.basic;
17:
18: import java.io.Serializable;
19:
20: /**
21: * Interface representing the identity of an individual domain object instance.
22: *
23: * <P>
24: * It should be noted that <code>AclObjectIdentity</code> instances are created
25: * in various locations throughout the package. As
26: * <code>AclObjectIdentity</code>s are used as the key for caching, it is
27: * essential that implementations provide methods so that object-equality
28: * rather than reference-equality can be relied upon by caches. In other
29: * words, a cache can consider two <code>AclObjectIdentity</code>s equal if
30: * <code>identity1.equals(identity2)</code>, rather than reference-equality of
31: * <code>identity1==identity2</code>.
32: * </p>
33: *
34: * <P>
35: * In practical terms this means you must implement the standard
36: * <code>java.lang.Object</code> methods shown below. Depending on your
37: * cache's internal structure, you may also need to implement special
38: * interfaces such as <code>java.util.Comparator</code> or
39: * <code>java.lang.Comparable</code>.
40: * </p>
41: *
42: * @author Ben Alex
43: * @version $Id: AclObjectIdentity.java 1784 2007-02-24 21:00:24Z luke_t $
44: */
45: public interface AclObjectIdentity extends Serializable {
46: //~ Methods ========================================================================================================
47:
48: /**
49: * Refer to the <code>java.lang.Object</code> documentation for the interface contract.
50: *
51: * @param obj to be compared
52: *
53: * @return <code>true</code> if the objects are equal, <code>false</code> otherwise
54: */
55: boolean equals(Object obj);
56:
57: /**
58: * Refer to the <code>java.lang.Object</code> documentation for the interface contract.
59: *
60: * @return a hash code representation of this object
61: */
62: int hashCode();
63: }
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