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.partition.impl.btree;
021
022
023 import java.util.Iterator;
024
025 import org.apache.directory.server.xdbm.ForwardIndexEntry;
026 import org.apache.directory.server.xdbm.IndexCursor;
027 import org.apache.directory.server.xdbm.IndexEntry;
028 import org.apache.directory.server.xdbm.ReverseIndexEntry;
029 import org.apache.directory.server.xdbm.Tuple;
030 import org.apache.directory.server.xdbm.TupleCursor;
031 import org.apache.directory.shared.ldap.cursor.ClosureMonitor;
032 import org.apache.directory.shared.ldap.cursor.Cursor;
033 import org.apache.directory.shared.ldap.cursor.CursorIterator;
034
035
036 /**
037 * A Cursor which adapts an underlying Tuple based Cursor to one which returns
038 * IndexEntry objects rather than tuples.
039 *
040 * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
041 * @version $Rev$
042 */
043 public class IndexCursorAdaptor<K, O, ID> implements IndexCursor<K, O, ID>
044 {
045 @SuppressWarnings("unchecked")
046 final Cursor<Tuple> wrappedCursor;
047 final ForwardIndexEntry<K, O, ID> forwardEntry;
048 final ReverseIndexEntry<K, O, ID> reverseEntry;
049
050
051 /**
052 * Creates an IndexCursorAdaptor which wraps and adapts a Cursor from a table to
053 * one which returns an IndexEntry.
054 *
055 * @param wrappedCursor the Cursor being adapted
056 * @param forwardIndex true for a cursor over a forward index, false for
057 * one over a reverse index
058 */
059 @SuppressWarnings("unchecked")
060 public IndexCursorAdaptor( Cursor<Tuple> wrappedCursor, boolean forwardIndex )
061 {
062 this.wrappedCursor = wrappedCursor;
063 if ( forwardIndex )
064 {
065 forwardEntry = new ForwardIndexEntry<K, O, ID>();
066 reverseEntry = null;
067 }
068 else
069 {
070 forwardEntry = null;
071 reverseEntry = new ReverseIndexEntry<K, O, ID>();
072 }
073 }
074
075
076 public boolean available()
077 {
078 return wrappedCursor.available();
079 }
080
081
082 @SuppressWarnings("unchecked")
083 public void beforeValue( ID id, K key ) throws Exception
084 {
085 if ( wrappedCursor instanceof TupleCursor )
086 {
087 ( ( TupleCursor ) wrappedCursor ).beforeValue( key, id );
088 }
089 }
090
091
092 @SuppressWarnings("unchecked")
093 public void afterValue( ID id, K key ) throws Exception
094 {
095 if ( wrappedCursor instanceof TupleCursor )
096 {
097 ( ( TupleCursor ) wrappedCursor ).afterValue( key, id );
098 }
099 }
100
101
102 public void before( IndexEntry<K, O, ID> element ) throws Exception
103 {
104 wrappedCursor.before( element.getTuple() );
105 }
106
107
108 public void after( IndexEntry<K, O, ID> element ) throws Exception
109 {
110 wrappedCursor.after( element.getTuple() );
111 }
112
113
114 public void beforeFirst() throws Exception
115 {
116 wrappedCursor.beforeFirst();
117 }
118
119
120 public void afterLast() throws Exception
121 {
122 wrappedCursor.afterLast();
123 }
124
125
126 public boolean first() throws Exception
127 {
128 return wrappedCursor.first();
129 }
130
131
132 public boolean last() throws Exception
133 {
134 return wrappedCursor.last();
135 }
136
137
138 public boolean isClosed() throws Exception
139 {
140 return wrappedCursor.isClosed();
141 }
142
143
144 public boolean previous() throws Exception
145 {
146 return wrappedCursor.previous();
147 }
148
149
150 public boolean next() throws Exception
151 {
152 return wrappedCursor.next();
153 }
154
155
156 @SuppressWarnings("unchecked")
157 public IndexEntry<K, O, ID> get() throws Exception
158 {
159 if ( forwardEntry != null )
160 {
161 Tuple<K, ID> tuple = wrappedCursor.get();
162 forwardEntry.setTuple( tuple, null );
163 return forwardEntry;
164 }
165 else
166 {
167 Tuple<ID, K> tuple = wrappedCursor.get();
168 reverseEntry.setTuple( tuple, null );
169 return reverseEntry;
170 }
171 }
172
173
174 public boolean isElementReused()
175 {
176 return true;
177 }
178
179
180 public final void setClosureMonitor( ClosureMonitor monitor )
181 {
182 wrappedCursor.setClosureMonitor( monitor );
183 }
184
185
186 public void close() throws Exception
187 {
188 wrappedCursor.close();
189 }
190
191
192 public void close( Exception reason ) throws Exception
193 {
194 wrappedCursor.close( reason );
195 }
196
197
198 public Iterator<IndexEntry<K, O, ID>> iterator()
199 {
200 return new CursorIterator<IndexEntry<K, O, ID>>( this );
201 }
202 }