1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one
3 * or more contributor license agreements. See the NOTICE file
4 * distributed with this work for additional information
5 * regarding copyright ownership. The ASF licenses this file
6 * to you under the Apache License, Version 2.0 (the
7 * "License"); you may not use this file except in compliance
8 * with the License. You may obtain a copy of the License at
9 *
10 * http://www.apache.org/licenses/LICENSE-2.0
11 *
12 * Unless required by applicable law or agreed to in writing,
13 * software distributed under the License is distributed on an
14 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
15 * KIND, either express or implied. See the License for the
16 * specific language governing permissions and limitations
17 * under the License.
18 *
19 */
20 package org.apache.directory.server.core.changelog;
21
22
23 import org.apache.directory.server.core.cursor.Cursor;
24
25
26 /**
27 * An optional search interface supported by TaggableChangeLogStores. This
28 * interface enables the:
29 *
30 * <ul>
31 * <li>lookup of tags by revision</li>
32 * <li>finding all tags</li>
33 * <li>finding tags before or after a revision</li>
34 * <li>finding tags in some revision range</li>
35 * </ul>
36 *
37 * While investigating these interface methods keep in mind that only one
38 * tag can exist on a revision. Unlike subversion which allows multiple
39 * tags on a revision we only allow at most one: more than one is pointless.
40 *
41 * Date wise searches for tags are not present within this interface since
42 * they should be used in conjunction with the ChangeLogSearchEngine which
43 * is by default supported by TaggableSearchableChangeLogStores. The
44 * ChangeLogSearchEngine can find revisions based on time descriptors and
45 * returned revisions can be checked for the presence of tags using this
46 * interface. The whole point to enabling both search engines in a single
47 * interfaces is because if you can search for tags you should be able to
48 * search for revisions: however the converse may not be the case.
49 *
50 * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
51 * @version $Rev$, $Date$
52 */
53 public interface TagSearchEngine
54 {
55 /**
56 * Gets the tag for a specific snapshot if that snapshot exists.
57 *
58 * @param revision the revision number to use to check for a snapshot
59 * @return the snapshot at the revision if one exists, otherwise null
60 * @throws Exception if there is a problem accessing the store
61 */
62 Tag lookup( long revision ) throws Exception;
63
64 /**
65 * Checks to see if a snapshot exists for a specific revision.
66 *
67 * @param revision the revision number to use to check for a snapshot
68 * @return true if a snapshot exists at the revision, false otherwise
69 * @throws Exception if there is a problem accessing the store
70 */
71 boolean has( long revision ) throws Exception;
72
73
74 // -----------------------------------------------------------------------
75 // Tag Search Operations
76 // -----------------------------------------------------------------------
77
78
79 /**
80 * Finds all the snapshot tags taken since revision 0 until the current
81 * revision.
82 *
83 * @param order the revision order in which to return snapshot tags
84 * @return a cursor containing the tags of all snapshots taken since revision 1
85 * @throws Exception if there is a problem accessing the store
86 */
87 Cursor<Tag> find( RevisionOrder order ) throws Exception;
88
89 /**
90 * Finds all the snapshot tags taken before a specific revision. If a tag
91 * exists at the revision parameter it will be returned as well.
92 *
93 * @param revision the revision number to get snapshots before
94 * @param order the revision order in which to return snapshot tags
95 * @return an enumeration over the tags of all snapshots taken before a revision inclusive
96 * @throws Exception if there is a problem accessing the store
97 * @throws IllegalArgumentException if the revision is greater than the current revision
98 * or less than 0.
99 */
100 Cursor<Tag> findBefore( long revision, RevisionOrder order ) throws Exception;
101
102 /**
103 * Finds all the snapshot tags taken after a specific revision. If a tag
104 * exists at the revision parameter it will be returned as well.
105 *
106 * @param revision the revision number to get snapshots after
107 * @param order the revision order in which to return snapshot tags
108 * @return an enumeration over the tags of all snapshots taken after a revision inclusive
109 * @throws Exception if there is a problem accessing the store
110 * @throws IllegalArgumentException if the revision is greater than the current revision
111 * or less than 0.
112 */
113 Cursor<Tag> findAfter( long revision, RevisionOrder order ) throws Exception;
114
115 /**
116 * Enumerates over the tags of all snapshots taken between a specific revision
117 * range inclusive. The first revision parameter should be less than or equal
118 * to the second revision parameter.
119 *
120 * @param startRevision the revision to start on inclusive
121 * @param endRevision the revision to end on inclusive
122 * @param order the revision order in which to return snapshot tags
123 * @return enumeration over all the snapshots taken in a revision range inclusive
124 * @throws Exception if there is a problem accessing the store
125 * @throws IllegalArgumentException if the revision range is not constructed properly
126 * or if either revision number is greater than the current revision or less than 0.
127 */
128 Cursor<Tag> find( long startRevision, long endRevision, RevisionOrder order )
129 throws Exception;
130 }