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.api.ldap.model.cursor;
21
22
23 import java.util.Iterator;
24
25 import org.apache.directory.api.i18n.I18n;
26
27
28 /**
29 * An Iterator over a Cursor so Cursors can be Iterable for using in foreach
30 * constructs.
31 *
32 * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
33 * @param <E> The type of element on which this cursor will iterate
34 */
35 public class CursorIterator<E> implements Iterator<E>
36 {
37 /** The inner cursor we will iterate */
38 private final Cursor<E> cursor;
39
40 /** A flag used to store the cursor state */
41 private boolean available;
42
43
44 /**
45 * Creates a new instance of CursorIterator.
46 *
47 * @param cursor The inner cursor
48 */
49 public CursorIterator( Cursor<E> cursor )
50 {
51 this.cursor = cursor;
52
53 try
54 {
55 this.available = cursor.next();
56 }
57 catch ( Exception e )
58 {
59 this.available = false;
60 }
61 }
62
63
64 /**
65 * {@inheritDoc}
66 */
67 public boolean hasNext()
68 {
69 return available;
70 }
71
72
73 /**
74 * {@inheritDoc}
75 */
76 public E next()
77 {
78 try
79 {
80 E element = cursor.get();
81 available = cursor.next();
82 return element;
83 }
84 catch ( Exception e )
85 {
86 throw new RuntimeException( I18n.err( I18n.ERR_02002_FAILURE_ON_UNDERLYING_CURSOR ), e );
87 }
88 }
89
90
91 /**
92 * {@inheritDoc}
93 */
94 public void remove()
95 {
96 throw new UnsupportedOperationException( I18n.err( I18n.ERR_02003_REMOVAL_NOT_SUPPORTED ) );
97 }
98 }