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.map;
18
19 import java.util.Iterator;
20 import java.util.Map;
21 import java.util.Set;
22
23 import org.apache.commons.collections4.MapIterator;
24 import org.apache.commons.collections4.ResettableIterator;
25
26 /**
27 * Adapts a Map entrySet to the MapIterator interface.
28 *
29 * @param <K> the type of the keys in the map
30 * @param <V> the type of the values in the map
31 *
32 * @since 4.0
33 */
34 public class EntrySetToMapIteratorAdapter<K, V> implements MapIterator<K, V>, ResettableIterator<K> {
35
36 /** The adapted Map entry Set. */
37 final Set<Map.Entry<K, V>> entrySet;
38
39 /** The resettable iterator in use. */
40 transient Iterator<Map.Entry<K, V>> iterator;
41
42 /** The currently positioned Map entry. */
43 transient Map.Entry<K, V> entry;
44
45 /**
46 * Create a new EntrySetToMapIteratorAdapter.
47 * @param entrySet the entrySet to adapt
48 */
49 public EntrySetToMapIteratorAdapter(final Set<Map.Entry<K, V>> entrySet) {
50 this.entrySet = entrySet;
51 reset();
52 }
53
54 /**
55 * Gets the currently active entry.
56 * @return Map.Entry<K, V>
57 */
58 protected synchronized Map.Entry<K, V> current() {
59 if (entry == null) {
60 throw new IllegalStateException();
61 }
62 return entry;
63 }
64
65 /**
66 * {@inheritDoc}
67 */
68 @Override
69 public K getKey() {
70 return current().getKey();
71 }
72
73 /**
74 * {@inheritDoc}
75 */
76 @Override
77 public V getValue() {
78 return current().getValue();
79 }
80
81 /**
82 * {@inheritDoc}
83 */
84 @Override
85 public boolean hasNext() {
86 return iterator.hasNext();
87 }
88
89 /**
90 * {@inheritDoc}
91 */
92 @Override
93 public K next() {
94 entry = iterator.next();
95 return getKey();
96 }
97
98 /**
99 * {@inheritDoc}
100 */
101 @Override
102 public void remove() {
103 iterator.remove();
104 entry = null;
105 }
106
107 /**
108 * {@inheritDoc}
109 */
110 @Override
111 public synchronized void reset() {
112 iterator = entrySet.iterator();
113 }
114
115 /**
116 * {@inheritDoc}
117 */
118 @Override
119 public V setValue(final V value) {
120 return current().setValue(value);
121 }
122 }