1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one or more
3 * contributor license agreements. See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The ASF licenses this file to You under the Apache license, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License. You may obtain a copy of the License at
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the license for the specific language governing permissions and
15 * limitations under the license.
16 */
17 package org.apache.log4j.helpers;
18
19 import java.util.Enumeration;
20 import java.util.NoSuchElementException;
21
22 /**
23 * An always-empty Enumerator.
24 *
25 * @since version 1.0
26 */
27 @SuppressWarnings("rawtypes")
28 public final class NullEnumeration implements Enumeration {
29 private static final NullEnumeration INSTANCE = new NullEnumeration();
30
31 private NullEnumeration() {
32 }
33
34 public static NullEnumeration getInstance() {
35 return INSTANCE;
36 }
37
38 @Override
39 public boolean hasMoreElements() {
40 return false;
41 }
42
43 @Override
44 public Object nextElement() {
45 throw new NoSuchElementException();
46 }
47 }