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 package org.apache.directory.server.core.partition.impl.btree;
020
021
022 import org.apache.directory.server.xdbm.Tuple;
023 import org.apache.directory.shared.ldap.NotImplementedException;
024 import org.apache.directory.shared.ldap.cursor.AbstractCursor;
025 import org.apache.directory.shared.ldap.cursor.InvalidCursorPositionException;
026
027 import java.util.Arrays;
028 import java.util.List;
029
030
031 /**
032 * A Cursor which returns the values of a single key as Tuples.
033 *
034 * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
035 * @version $Rev$, $Date$
036 */
037 public class ValueArrayCursor<K,V> extends AbstractCursor<Tuple>
038 {
039 private static final int BEFORE_FIRST = -1;
040
041 private final K key;
042 private final List<V> values;
043 private final Tuple<K,V> tuple = new Tuple<K,V>();
044
045 private int pos = BEFORE_FIRST;
046
047
048 public ValueArrayCursor( final K key, final V[] values )
049 {
050 this.key = key;
051 this.tuple.setKey( key );
052 this.values = Arrays.asList( values );
053 }
054
055
056 public ValueArrayCursor( final K key, final List<V> values )
057 {
058 this.key = key;
059 this.tuple.setKey( key );
060 this.values = values;
061 }
062
063
064 public boolean available()
065 {
066 return inRangeOnValue();
067 }
068
069
070 public void before( Tuple element ) throws Exception
071 {
072 throw new NotImplementedException();
073 }
074
075
076 public void after( Tuple element ) throws Exception
077 {
078 throw new NotImplementedException();
079 }
080
081
082 public void beforeFirst() throws Exception
083 {
084 checkNotClosed( "beforeFirst()" );
085 pos = BEFORE_FIRST;
086 }
087
088
089 public void afterLast() throws Exception
090 {
091 checkNotClosed( "afterLast()" );
092 pos = values.size();
093 }
094
095
096 public boolean absolute( int absolutePosition ) throws Exception
097 {
098 checkNotClosed( "absolute()" );
099 if ( absolutePosition >= values.size() )
100 {
101 pos = values.size();
102 return false;
103 }
104
105 if ( absolutePosition < 0 )
106 {
107 pos = BEFORE_FIRST;
108 return false;
109 }
110
111 pos = absolutePosition;
112 return true;
113 }
114
115
116 public boolean first() throws Exception
117 {
118 checkNotClosed( "first()" );
119 pos = 0;
120 return true;
121 }
122
123
124 public boolean last() throws Exception
125 {
126 checkNotClosed( "last()" );
127 pos = values.size() - 1;
128 return true;
129 }
130
131
132 public boolean isFirst() throws Exception
133 {
134 checkNotClosed( "isFirst()" );
135 return pos == 0;
136 }
137
138
139 public boolean isLast() throws Exception
140 {
141 checkNotClosed( "isLast()" );
142 return pos == values.size() - 1;
143 }
144
145
146 public boolean isAfterLast() throws Exception
147 {
148 checkNotClosed( "isAfterLast()" );
149 return pos == values.size();
150 }
151
152
153 public boolean isBeforeFirst() throws Exception
154 {
155 checkNotClosed( "isBeforeFirst()" );
156 return pos == BEFORE_FIRST;
157 }
158
159
160 public boolean previous() throws Exception
161 {
162 checkNotClosed( "previous()" );
163 if ( pos <= BEFORE_FIRST )
164 {
165 return false;
166 }
167
168 pos--;
169 return inRangeOnValue();
170 }
171
172
173 private boolean inRangeOnValue()
174 {
175 return pos > BEFORE_FIRST && pos < values.size();
176 }
177
178
179 public boolean next() throws Exception
180 {
181 checkNotClosed( "next()" );
182 if ( pos >= values.size() )
183 {
184 return false;
185 }
186
187 pos++;
188 return inRangeOnValue();
189 }
190
191
192 public Tuple get() throws Exception
193 {
194 checkNotClosed( "get()" );
195 if ( inRangeOnValue() )
196 {
197 return tuple.setBoth( key, values.get( pos ) );
198 }
199
200 throw new InvalidCursorPositionException( "Cursor pos (" + pos
201 + ") not in value range [0-" + ( values.size() - 1 )+ "]" );
202 }
203
204
205 public boolean isElementReused()
206 {
207 return true;
208 }
209 }