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.mavibot.btree;
21
22
23 import java.io.IOException;
24
25 import org.apache.directory.mavibot.btree.exception.EndOfFileExceededException;
26 import org.apache.directory.mavibot.btree.exception.KeyNotFoundException;
27 import org.apache.directory.mavibot.btree.BTree;
28
29
30 /**
31 * A class that encapsulate the values into an sub-btree
32 *
33 * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
34 */
35 /* No qualifier */class ValueBTreeCursor<V> implements ValueCursor<V>
36 {
37 /** Store the current position in the array or in the BTree */
38 private KeyCursor<V> cursor;
39
40 /** The Value sub-btree */
41 private BTree<V, V> valueBtree;
42
43
44 /**
45 * Create an instance
46 */
47 public ValueBTreeCursor( BTree<V, V> valueBtree )
48 {
49 this.valueBtree = valueBtree;
50
51 // Start at -1 to be positioned before the first element
52 try
53 {
54 if ( valueBtree != null )
55 {
56 cursor = valueBtree.browseKeys();
57 }
58 }
59 catch ( IOException e )
60 {
61 // TODO Auto-generated catch block
62 e.printStackTrace();
63 }
64 catch ( KeyNotFoundException knfe )
65 {
66 // TODO Auto-generated catch block
67 knfe.printStackTrace();
68 }
69 }
70
71
72 /**
73 * {@inheritDoc}}
74 */
75 @Override
76 public boolean hasNext()
77 {
78 if ( cursor == null )
79 {
80 return false;
81 }
82 else
83 {
84 try
85 {
86 return cursor.hasNext();
87 }
88 catch ( EndOfFileExceededException e )
89 {
90 e.printStackTrace();
91 return false;
92 }
93 catch ( IOException e )
94 {
95 e.printStackTrace();
96 return false;
97 }
98 }
99 }
100
101
102 /**
103 * {@inheritDoc}}
104 */
105 public V next()
106 {
107 try
108 {
109 return cursor.next();
110 }
111 catch ( EndOfFileExceededException e )
112 {
113 e.printStackTrace();
114 return null;
115 }
116 catch ( IOException e )
117 {
118 e.printStackTrace();
119 return null;
120 }
121 }
122
123
124 /**
125 * {@inheritDoc}}
126 */
127 @Override
128 public boolean hasPrev() throws EndOfFileExceededException, IOException
129 {
130 if ( cursor == null )
131 {
132 return false;
133 }
134 else
135 {
136 try
137 {
138 return cursor.hasPrev();
139 }
140 catch ( EndOfFileExceededException e )
141 {
142 e.printStackTrace();
143 return false;
144 }
145 catch ( IOException e )
146 {
147 e.printStackTrace();
148 return false;
149 }
150 }
151 }
152
153
154 /**
155 * {@inheritDoc}}
156 */
157 @Override
158 public void close()
159 {
160 if ( cursor != null )
161 {
162 cursor.close();
163 }
164 }
165
166
167 /**
168 * {@inheritDoc}}
169 */
170 @Override
171 public void beforeFirst() throws IOException
172 {
173 if ( cursor != null )
174 {
175 cursor.beforeFirst();
176 }
177 }
178
179
180 /**
181 * {@inheritDoc}}
182 */
183 @Override
184 public void afterLast() throws IOException
185 {
186 if ( cursor != null )
187 {
188 cursor.afterLast();
189 }
190 }
191
192
193 /**
194 * {@inheritDoc}}
195 */
196 @Override
197 public V prev() throws EndOfFileExceededException, IOException
198 {
199 try
200 {
201 return cursor.prev();
202 }
203 catch ( EndOfFileExceededException e )
204 {
205 e.printStackTrace();
206 return null;
207 }
208 catch ( IOException e )
209 {
210 e.printStackTrace();
211 return null;
212 }
213 }
214
215
216 /**
217 * {@inheritDoc}
218 */
219 @Override
220 public int size()
221 {
222 return ( int ) valueBtree.getNbElems();
223 }
224
225
226 /**
227 * @see Object#toString()
228 */
229 public String toString()
230 {
231 return "BTreeCursor";
232 }
233 }