001 /*
002 * Licensed to the Apache Software Foundation (ASF) under one
003 * or more contributor license agreements. See the NOTICE file
004 * distributed with this work for additional information
005 * regarding copyright ownership. The ASF licenses this file
006 * to you under the Apache License, Version 2.0 (the
007 * "License"); you may not use this file except in compliance
008 * with the License. You may obtain a copy of the License at
009 *
010 * http://www.apache.org/licenses/LICENSE-2.0
011 *
012 * Unless required by applicable law or agreed to in writing,
013 * software distributed under the License is distributed on an
014 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
015 * KIND, either express or implied. See the License for the
016 * specific language governing permissions and limitations
017 * under the License.
018 *
019 */
020 package org.apache.directory.server.core.changelog;
021
022
023 import org.apache.directory.shared.ldap.cursor.Cursor;
024
025
026 /**
027 * An optional search interface supported by TaggableChangeLogStores. This
028 * interface enables the:
029 *
030 * <ul>
031 * <li>lookup of tags by revision</li>
032 * <li>finding all tags</li>
033 * <li>finding tags before or after a revision</li>
034 * <li>finding tags in some revision range</li>
035 * </ul>
036 *
037 * While investigating these interface methods keep in mind that only one
038 * tag can exist on a revision. Unlike subversion which allows multiple
039 * tags on a revision we only allow at most one: more than one is pointless.
040 *
041 * Date wise searches for tags are not present within this interface since
042 * they should be used in conjunction with the ChangeLogSearchEngine which
043 * is by default supported by TaggableSearchableChangeLogStores. The
044 * ChangeLogSearchEngine can find revisions based on time descriptors and
045 * returned revisions can be checked for the presence of tags using this
046 * interface. The whole point to enabling both search engines in a single
047 * interfaces is because if you can search for tags you should be able to
048 * search for revisions: however the converse may not be the case.
049 *
050 * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
051 * @version $Rev$, $Date$
052 */
053 public interface TagSearchEngine
054 {
055 /**
056 * Gets the tag for a specific snapshot if that snapshot exists.
057 *
058 * @param revision the revision number to use to check for a snapshot
059 * @return the snapshot at the revision if one exists, otherwise null
060 * @throws Exception if there is a problem accessing the store
061 */
062 Tag lookup( long revision ) throws Exception;
063
064 /**
065 * Checks to see if a snapshot exists for a specific revision.
066 *
067 * @param revision the revision number to use to check for a snapshot
068 * @return true if a snapshot exists at the revision, false otherwise
069 * @throws Exception if there is a problem accessing the store
070 */
071 boolean has( long revision ) throws Exception;
072
073
074 // -----------------------------------------------------------------------
075 // Tag Search Operations
076 // -----------------------------------------------------------------------
077
078
079 /**
080 * Finds all the snapshot tags taken since revision 0 until the current
081 * revision.
082 *
083 * @param order the revision order in which to return snapshot tags
084 * @return a cursor containing the tags of all snapshots taken since revision 1
085 * @throws Exception if there is a problem accessing the store
086 */
087 Cursor<Tag> find( RevisionOrder order ) throws Exception;
088
089 /**
090 * Finds all the snapshot tags taken before a specific revision. If a tag
091 * exists at the revision parameter it will be returned as well.
092 *
093 * @param revision the revision number to get snapshots before
094 * @param order the revision order in which to return snapshot tags
095 * @return an enumeration over the tags of all snapshots taken before a revision inclusive
096 * @throws Exception if there is a problem accessing the store
097 * @throws IllegalArgumentException if the revision is greater than the current revision
098 * or less than 0.
099 */
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 }