    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.Comparator;
    025import java.util.Map;
    026import java.util.Set;
    027import java.util.SortedMap;
    028
    029import org.apache.commons.collections4.Unmodifiable;
    030import org.apache.commons.collections4.collection.UnmodifiableCollection;
    031import org.apache.commons.collections4.set.UnmodifiableSet;
    032
    033/**
    034 * Decorates another {@code SortedMap} to ensure it can't be altered.
    035 * <p>
    036 * This class is Serializable from Commons Collections 3.1.
    037 * </p>
    038 * <p>
    039 * Attempts to modify it will result in an UnsupportedOperationException.
    040 * </p>
    041 *
    042 * @param <K> the type of the keys in this map
    043 * @param <V> the type of the values in this map
    044 * @since 3.0
    045 */
    046public final class UnmodifiableSortedMap<K, V>
    047        extends AbstractSortedMapDecorator<K, V>
    048        implements Unmodifiable, Serializable {
    049
    050    /** Serialization version */
    051    private static final long serialVersionUID = 5805344239827376360L;
    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 unmodifiable sorted map
    060     * @throws NullPointerException if map is null
    061     * @since 4.0
    062     */
    063    public static <K, V> SortedMap<K, V> unmodifiableSortedMap(final SortedMap<K, ? extends V> map) {
    064        if (map instanceof Unmodifiable) {
    065            @SuppressWarnings("unchecked") // safe to upcast
    066            final SortedMap<K, V> tmpMap = (SortedMap<K, V>) map;
    067            return tmpMap;
    068        }
    069        return new UnmodifiableSortedMap<>(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 UnmodifiableSortedMap(final SortedMap<K, ? extends V> map) {
    080        super((SortedMap<K, V>) map);
    081    }
    082
    083    @Override
    084    public void clear() {
    085        throw new UnsupportedOperationException();
    086    }
    087
    088    @Override
    089    public Comparator<? super K> comparator() {
    090        return decorated().comparator();
    091    }
    092
    093    @Override
    094    public Set<Map.Entry<K, V>> entrySet() {
    095        return UnmodifiableEntrySet.unmodifiableEntrySet(super.entrySet());
    096    }
    097
    098    @Override
    099    public K firstKey() {
    100        return decorated().firstKey();
    101    }
    102
    103    @Override
    104    public SortedMap<K, V> headMap(final K toKey) {
    105        return new UnmodifiableSortedMap<>(decorated().headMap(toKey));
    106    }
    107
    108    @Override
    109    public Set<K> keySet() {
    110        return UnmodifiableSet.unmodifiableSet(super.keySet());
    111    }
    112
    113    @Override
    114    public K lastKey() {
    115        return decorated().lastKey();
    116    }
    117
    118    @Override
    119    public V put(final K key, final V value) {
    120        throw new UnsupportedOperationException();
    121    }
    122
    123    @Override
    124    public void putAll(final Map<? extends K, ? extends V> mapToCopy) {
    125        throw new UnsupportedOperationException();
    126    }
    127
    128    /**
    129     * Read the map in using a custom routine.
    130     *
    131     * @param in  the input stream
    132     * @throws IOException if an error occurs while reading from the stream
    133     * @throws ClassNotFoundException if an object read from the stream can not be loaded
    134     * @since 3.1
    135     */
    136    @SuppressWarnings("unchecked")
    137    private void readObject(final ObjectInputStream in) throws IOException, ClassNotFoundException {
    138        in.defaultReadObject();
    139        map = (Map<K, V>) in.readObject();
    140    }
    141
    142    @Override
    143    public V remove(final Object key) {
    144        throw new UnsupportedOperationException();
    145    }
    146
    147    @Override
    148    public SortedMap<K, V> subMap(final K fromKey, final K toKey) {
    149        return new UnmodifiableSortedMap<>(decorated().subMap(fromKey, toKey));
    150    }
    151
    152    @Override
    153    public SortedMap<K, V> tailMap(final K fromKey) {
    154        return new UnmodifiableSortedMap<>(decorated().tailMap(fromKey));
    155    }
    156
    157    @Override
    158    public Collection<V> values() {
    159        return UnmodifiableCollection.unmodifiableCollection(super.values());
    160    }
    161
    162    /**
    163     * Write the map out using a custom routine.
    164     *
    165     * @param out  the output stream
    166     * @throws IOException if an error occurs while writing to the stream
    167     * @since 3.1
    168     */
    169    private void writeObject(final ObjectOutputStream out) throws IOException {
    170        out.defaultWriteObject();
    171        out.writeObject(map);
    172    }
    173
    174}