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