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.iterators;
018
019import org.apache.commons.collections4.OrderedMapIterator;
020import org.apache.commons.collections4.Unmodifiable;
021
022/**
023 * Decorates an ordered map iterator such that it cannot be modified.
024 * <p>
025 * Attempts to modify it will result in an UnsupportedOperationException.
026 *
027 * @since 3.0
028 * @version $Id: UnmodifiableOrderedMapIterator.html 972421 2015-11-14 20:00:04Z tn $
029 */
030public final class UnmodifiableOrderedMapIterator<K, V> implements OrderedMapIterator<K, V>,
031        Unmodifiable {
032
033    /** The iterator being decorated */
034    private final OrderedMapIterator<? extends K, ? extends V> iterator;
035
036    //-----------------------------------------------------------------------
037    /**
038     * Decorates the specified iterator such that it cannot be modified.
039     *
040     * @param <K>  the key type
041     * @param <V>  the value type
042     * @param iterator  the iterator to decorate
043     * @return a new unmodifiable ordered map iterator
044     * @throws IllegalArgumentException if the iterator is null
045     */
046    public static <K, V> OrderedMapIterator<K, V> unmodifiableOrderedMapIterator(
047            final OrderedMapIterator<K, ? extends V> iterator) {
048
049        if (iterator == null) {
050            throw new IllegalArgumentException("OrderedMapIterator must not be null");
051        }
052        if (iterator instanceof Unmodifiable) {
053            @SuppressWarnings("unchecked") // safe to upcast
054            final OrderedMapIterator<K, V> tmpIterator = (OrderedMapIterator<K, V>) iterator;
055            return tmpIterator;
056        }
057        return new UnmodifiableOrderedMapIterator<K, V>(iterator);
058    }
059
060    //-----------------------------------------------------------------------
061    /**
062     * Constructor.
063     *
064     * @param iterator  the iterator to decorate
065     */
066    private UnmodifiableOrderedMapIterator(final OrderedMapIterator<K, ? extends V> iterator) {
067        super();
068        this.iterator = iterator;
069    }
070
071    //-----------------------------------------------------------------------
072    public boolean hasNext() {
073        return iterator.hasNext();
074    }
075
076    public K next() {
077        return iterator.next();
078    }
079
080    public boolean hasPrevious() {
081        return iterator.hasPrevious();
082    }
083
084    public K previous() {
085        return iterator.previous();
086    }
087
088    public K getKey() {
089        return iterator.getKey();
090    }
091
092    public V getValue() {
093        return iterator.getValue();
094    }
095
096    public V setValue(final V value) {
097        throw new UnsupportedOperationException("setValue() is not supported");
098    }
099
100    public void remove() {
101        throw new UnsupportedOperationException("remove() is not supported");
102    }
103
104}