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 * https://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.util;
21
22
23 import java.util.NoSuchElementException;
24
25 import javax.naming.NamingException;
26 import javax.naming.NamingEnumeration;
27
28
29 /**
30 * An empty NamingEnumeration without any values: meaning
31 * hasMore/hasMoreElements() always returns false, and next/nextElement() always
32 * throws a NoSuchElementException.
33 *
34 * @param <T> The element in the enumeration
35 *
36 * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
37 */
38 public class EmptyEnumeration<T> implements NamingEnumeration<T>
39 {
40 /**
41 * @see javax.naming.NamingEnumeration#close()
42 */
43 @Override
44 public void close()
45 {
46 }
47
48
49 /**
50 * Always returns false.
51 *
52 * @see javax.naming.NamingEnumeration#hasMore()
53 */
54 @Override
55 public boolean hasMore() throws NamingException
56 {
57 return false;
58 }
59
60
61 /**
62 * Always throws NoSuchElementException.
63 *
64 * @see javax.naming.NamingEnumeration#next()
65 */
66 @Override
67 public T next() throws NamingException
68 {
69 throw new NoSuchElementException();
70 }
71
72
73 /**
74 * Always return false.
75 *
76 * @see java.util.Enumeration#hasMoreElements()
77 */
78 @Override
79 public boolean hasMoreElements()
80 {
81 return false;
82 }
83
84
85 /**
86 * Always throws NoSuchElementException.
87 *
88 * @see java.util.Enumeration#nextElement()
89 */
90 @Override
91 public T nextElement()
92 {
93 throw new NoSuchElementException();
94 }
95
96 }