    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.io.IOException;
    020import java.io.ObjectInputStream;
    021import java.io.ObjectOutputStream;
    022import java.io.Serializable;
    023import java.util.Collection;
    024import java.util.Map;
    025import java.util.Set;
    026
    027import org.apache.commons.collections4.OrderedMap;
    028import org.apache.commons.collections4.OrderedMapIterator;
    029import org.apache.commons.collections4.Unmodifiable;
    030import org.apache.commons.collections4.collection.UnmodifiableCollection;
    031import org.apache.commons.collections4.iterators.UnmodifiableOrderedMapIterator;
    032import org.apache.commons.collections4.set.UnmodifiableSet;
    033
    034/**
    035 * Decorates another {@code OrderedMap} to ensure it can't be altered.
    036 * <p>
    037 * This class is Serializable from Commons Collections 3.1.
    038 * </p>
    039 * <p>
    040 * Attempts to modify it will result in an UnsupportedOperationException.
    041 * </p>
    042 *
    043 * @param <K> the type of the keys in this map
    044 * @param <V> the type of the values in this map
    045 * @since 3.0
    046 */
    047public final class UnmodifiableOrderedMap<K, V> extends AbstractOrderedMapDecorator<K, V> implements
    048        Unmodifiable, Serializable {
    049
    050    /** Serialization version */
    051    private static final long serialVersionUID = 8136428161720526266L;
    052
    053    /**
    054     * Factory method to create an unmodifiable sorted map.
    055     *
    056     * @param <K>  the key type
    057     * @param <V>  the value type
    058     * @param map  the map to decorate, must not be null
    059     * @return a new ordered map
    060     * @throws NullPointerException if map is null
    061     * @since 4.0
    062     */
    063    public static <K, V> OrderedMap<K, V> unmodifiableOrderedMap(final OrderedMap<? extends K, ? extends V> map) {
    064        if (map instanceof Unmodifiable) {
    065            @SuppressWarnings("unchecked") // safe to upcast
    066            final OrderedMap<K, V> tmpMap = (OrderedMap<K, V>) map;
    067            return tmpMap;
    068        }
    069        return new UnmodifiableOrderedMap<>(map);
    070    }
    071
    072    /**
    073     * Constructor that wraps (not copies).
    074     *
    075     * @param map  the map to decorate, must not be null
    076     * @throws NullPointerException if map is null
    077     */
    078    @SuppressWarnings("unchecked") // safe to upcast
    079    private UnmodifiableOrderedMap(final OrderedMap<? extends K, ? extends V> map) {
    080        super((OrderedMap<K, V>) map);
    081    }
    082
    083    @Override
    084    public void clear() {
    085        throw new UnsupportedOperationException();
    086    }
    087
    088    @Override
    089    public Set<Map.Entry<K, V>> entrySet() {
    090        final Set<Map.Entry<K, V>> set = super.entrySet();
    091        return UnmodifiableEntrySet.unmodifiableEntrySet(set);
    092    }
    093
    094    @Override
    095    public Set<K> keySet() {
    096        final Set<K> set = super.keySet();
    097        return UnmodifiableSet.unmodifiableSet(set);
    098    }
    099
    100    @Override
    101    public OrderedMapIterator<K, V> mapIterator() {
    102        final OrderedMapIterator<K, V> it = decorated().mapIterator();
    103        return UnmodifiableOrderedMapIterator.unmodifiableOrderedMapIterator(it);
    104    }
    105
    106    @Override
    107    public V put(final K key, final V value) {
    108        throw new UnsupportedOperationException();
    109    }
    110
    111    @Override
    112    public void putAll(final Map<? extends K, ? extends V> mapToCopy) {
    113        throw new UnsupportedOperationException();
    114    }
    115
    116    /**
    117     * Read the map in using a custom routine.
    118     *
    119     * @param in  the input stream
    120     * @throws IOException if an error occurs while reading from the stream
    121     * @throws ClassNotFoundException if an object read from the stream can not be loaded
    122     * @since 3.1
    123     */
    124    @SuppressWarnings("unchecked") // (1) should only fail if input stream is incorrect
    125    private void readObject(final ObjectInputStream in) throws IOException, ClassNotFoundException {
    126        in.defaultReadObject();
    127        map = (Map<K, V>) in.readObject(); // (1)
    128    }
    129
    130    @Override
    131    public V remove(final Object key) {
    132        throw new UnsupportedOperationException();
    133    }
    134
    135    @Override
    136    public Collection<V> values() {
    137        final Collection<V> coll = super.values();
    138        return UnmodifiableCollection.unmodifiableCollection(coll);
    139    }
    140
    141    /**
    142     * Write the map out using a custom routine.
    143     *
    144     * @param out  the output stream
    145     * @throws IOException if an error occurs while writing to the stream
    146     * @since 3.1
    147     */
    148    private void writeObject(final ObjectOutputStream out) throws IOException {
    149        out.defaultWriteObject();
    150        out.writeObject(map);
    151    }
    152
    153}