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 public final class NullIterator<T> implements Iterator<T>
28 {
29 //~ Static fields/initializers -----------------------------------------------------------------
30
31 private static final NullIterator<?> INSTANCE = new NullIterator<Object>();
32
33 //~ Methods ------------------------------------------------------------------------------------
34
35 @SuppressWarnings("unchecked")
36 public static final <T> Iterator<T> instance()
37 {
38 return (Iterator<T>) INSTANCE;
39 }
40
41 public boolean hasNext()
42 {
43 return false;
44 }
45
46 public T next()
47 {
48 throw new NoSuchElementException();
49 }
50
51 public void remove()
52 {
53 throw new UnsupportedOperationException(this.getClass().getName() + " UnsupportedOperationException");
54 }
55 }