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 org.apache.directory.shared.ldap.NotImplementedException;
024 import org.apache.directory.server.xdbm.ForwardIndexEntry;
025 import org.apache.directory.server.xdbm.IndexEntry;
026 import org.apache.directory.server.xdbm.Tuple;
027
028 import java.util.NoSuchElementException;
029 import java.util.regex.Pattern;
030
031 import javax.naming.NamingEnumeration;
032 import javax.naming.NamingException;
033
034
035 /**
036 * A NamingEnumeration over an Index which returns IndexRecords.
037 *
038 * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
039 * @version $Rev: 640657 $
040 */
041 public class IndexEnumeration<T> implements NamingEnumeration<IndexEntry>
042 {
043 /** */
044 private final Pattern re;
045 /** */
046 private final ForwardIndexEntry tmp = new ForwardIndexEntry();
047 /** */
048 private final ForwardIndexEntry returned = new ForwardIndexEntry();
049 /** */
050 private final ForwardIndexEntry prefetched = new ForwardIndexEntry();
051 /** */
052 private final boolean swapKeyVal;
053 /** */
054 private final NamingEnumeration<Tuple> underlying;
055
056 /** */
057 private boolean hasMore = true;
058
059
060 // ------------------------------------------------------------------------
061 // C O N S T R U C T O R S
062 // ------------------------------------------------------------------------
063
064
065 public IndexEnumeration( NamingEnumeration<Tuple> list ) throws NamingException
066 {
067 this( list, false, null );
068 }
069
070
071 public IndexEnumeration( NamingEnumeration<Tuple> list, boolean swapKeyVal ) throws NamingException
072 {
073 this( list, swapKeyVal, null );
074 }
075
076
077 public IndexEnumeration( NamingEnumeration<Tuple> list, boolean swapKeyVal, Pattern regex )
078 throws NamingException
079 {
080 re = regex;
081 underlying = list;
082 this.swapKeyVal = swapKeyVal;
083
084 if ( !underlying.hasMore() )
085 {
086 hasMore = false;
087 return;
088 }
089
090 prefetch();
091 }
092
093
094 // ------------------------------------------------------------------------
095 // NamingEnumeration Interface Methods
096 // ------------------------------------------------------------------------
097
098 /**
099 * @see javax.naming.NamingEnumeration#next()
100 */
101 public IndexEntry next() throws NamingException
102 {
103 returned.copy( prefetched );
104 prefetch();
105 return returned;
106 }
107
108
109 /**
110 * @see java.util.Enumeration#nextElement()
111 */
112 public IndexEntry nextElement()
113 {
114 try
115 {
116 return next();
117 }
118 catch ( NamingException ne )
119 {
120 throw new NoSuchElementException();
121 }
122 }
123
124
125 /**
126 * @see javax.naming.NamingEnumeration#hasMore()
127 */
128 public boolean hasMore()
129 {
130 return hasMore;
131 }
132
133
134 /**
135 * @see javax.naming.NamingEnumeration#hasMoreElements()
136 */
137 public boolean hasMoreElements()
138 {
139 return hasMore;
140 }
141
142
143 /**
144 * @see javax.naming.NamingEnumeration#close()
145 */
146 public void close() throws NamingException
147 {
148 hasMore = false;
149 underlying.close();
150 }
151
152
153 // ------------------------------------------------------------------------
154 // Private Methods
155 // ------------------------------------------------------------------------
156
157
158 private void prefetch() throws NamingException
159 {
160 while ( underlying.hasMore() )
161 {
162 Tuple tuple = underlying.next();
163
164 if ( swapKeyVal )
165 {
166 throw new NotImplementedException();
167 // tmp.setSwapped( tuple, null );
168 }
169 else
170 {
171 tmp.setTuple( tuple, null );
172 }
173
174 // If regex is null just transfer into prefetched from tmp record
175 // but if it is not then use it to match. Successful match shorts
176 // while loop.
177 if ( null == re || re.matcher( ( String ) tmp.getValue() ).matches() )
178 {
179 prefetched.copy( tmp );
180 return;
181 }
182 }
183
184 // If we got down here then cursor has been consumed without a match!
185 hasMore = false;
186 }
187 }