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 package org.apache.myfaces.shared.util;
20
21 import java.util.Iterator;
22 import java.util.NoSuchElementException;
23
24 /**
25 * Iterator without elements
26 *
27 * @author Anton Koinov (latest modification by $Author: bommel $)
28 * @version $Revision: 1187700 $ $Date: 2011-10-22 07:19:37 -0500 (Sat, 22 Oct 2011) $
29 */
30 public final class NullIterator<T> implements Iterator<T>
31 {
32 //~ Static fields/initializers -----------------------------------------------------------------
33
34 private static final NullIterator<?> INSTANCE = new NullIterator<Object>();
35
36 //~ Methods ------------------------------------------------------------------------------------
37
38 @SuppressWarnings("unchecked")
39 public static final <T> Iterator<T> instance()
40 {
41 return (Iterator<T>) INSTANCE;
42 }
43
44 public boolean hasNext()
45 {
46 return false;
47 }
48
49 public T next()
50 {
51 throw new NoSuchElementException();
52 }
53
54 public void remove()
55 {
56 throw new UnsupportedOperationException(this.getClass().getName() + " UnsupportedOperationException");
57 }
58 }