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.commons.collections4.iterators;
18
19 import java.util.Enumeration;
20 import java.util.Iterator;
21
22 /**
23 * Adapter to make an {@link Iterator Iterator} instance appear to be an
24 * {@link Enumeration Enumeration} instance.
25 *
26 * @param <E> the type of elements returned by this iterator.
27 * @since 1.0
28 */
29 public class IteratorEnumeration<E> implements Enumeration<E> {
30
31 /** The iterator being decorated. */
32 private Iterator<? extends E> iterator;
33
34 /**
35 * Constructs a new {@code IteratorEnumeration} that will not function
36 * until {@link #setIterator(Iterator) setIterator} is invoked.
37 */
38 public IteratorEnumeration() {
39 }
40
41 /**
42 * Constructs a new {@code IteratorEnumeration} that will use the given
43 * iterator.
44 *
45 * @param iterator the iterator to use
46 */
47 public IteratorEnumeration(final Iterator<? extends E> iterator) {
48 this.iterator = iterator;
49 }
50
51 /**
52 * Returns the underlying iterator.
53 *
54 * @return the underlying iterator
55 */
56 public Iterator<? extends E> getIterator() {
57 return iterator;
58 }
59
60 /**
61 * Returns true if the underlying iterator has more elements.
62 *
63 * @return true if the underlying iterator has more elements
64 */
65 @Override
66 public boolean hasMoreElements() {
67 return iterator.hasNext();
68 }
69
70 /**
71 * Returns the next element from the underlying iterator.
72 *
73 * @return the next element from the underlying iterator.
74 * @throws java.util.NoSuchElementException if the underlying iterator has
75 * no more elements
76 */
77 @Override
78 public E nextElement() {
79 return iterator.next();
80 }
81
82 /**
83 * Sets the underlying iterator.
84 *
85 * @param iterator the new underlying iterator
86 */
87 public void setIterator(final Iterator<? extends E> iterator) {
88 this.iterator = iterator;
89 }
90
91 }