001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017package org.apache.commons.collections4.map;
018
019import java.util.Iterator;
020import java.util.Map;
021import java.util.Set;
022
023import org.apache.commons.collections4.MapIterator;
024import org.apache.commons.collections4.ResettableIterator;
025
026/**
027 * Adapts a Map entrySet to the MapIterator interface.
028 *
029 * @since 4.0
030 * @version $Id: EntrySetToMapIteratorAdapter.html 972421 2015-11-14 20:00:04Z tn $
031 */
032public class EntrySetToMapIteratorAdapter<K, V> implements MapIterator<K, V>, ResettableIterator<K> {
033
034    /** The adapted Map entry Set. */
035    Set<Map.Entry<K, V>> entrySet;
036
037    /** The resettable iterator in use. */
038    transient Iterator<Map.Entry<K, V>> iterator;
039
040    /** The currently positioned Map entry. */
041    transient Map.Entry<K, V> entry;
042
043    /**
044     * Create a new EntrySetToMapIteratorAdapter.
045     * @param entrySet  the entrySet to adapt
046     */
047    public EntrySetToMapIteratorAdapter(final Set<Map.Entry<K, V>> entrySet) {
048        this.entrySet = entrySet;
049        reset();
050    }
051
052    /**
053     * {@inheritDoc}
054     */
055    public K getKey() {
056        return current().getKey();
057    }
058
059    /**
060     * {@inheritDoc}
061     */
062    public V getValue() {
063        return current().getValue();
064    }
065
066    /**
067     * {@inheritDoc}
068     */
069    public V setValue(final V value) {
070        return current().setValue(value);
071    }
072
073    /**
074     * {@inheritDoc}
075     */
076    public boolean hasNext() {
077        return iterator.hasNext();
078    }
079
080    /**
081     * {@inheritDoc}
082     */
083    public K next() {
084        entry = iterator.next();
085        return getKey();
086    }
087
088    /**
089     * {@inheritDoc}
090     */
091    public synchronized void reset() {
092        iterator = entrySet.iterator();
093    }
094
095    /**
096     * {@inheritDoc}
097     */
098    public void remove() {
099        iterator.remove();
100        entry = null;
101    }
102
103    /**
104     * Get the currently active entry.
105     * @return Map.Entry<K, V>
106     */
107    protected synchronized Map.Entry<K, V> current() {
108        if (entry == null) {
109            throw new IllegalStateException();
110        }
111        return entry;
112    }
113}