/*

 * Licensed to the Apache Software Foundation (ASF) under one or more

 * contributor license agreements.  See the NOTICE file distributed with

 * this work for additional information regarding copyright ownership.

 * The ASF licenses this file to You under the Apache License, Version 2.0

 * (the "License"); you may not use this file except in compliance with

 * the License.  You may obtain a copy of the License at

 *

 *      http://www.apache.org/licenses/LICENSE-2.0

 *

 * Unless required by applicable law or agreed to in writing, software

 * distributed under the License is distributed on an "AS IS" BASIS,

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 * See the License for the specific language governing permissions and

 * limitations under the License.

 */

package org.apache.commons.collections4.multimap;

import java.util.Collection;

import java.util.Map;

import java.util.Map.Entry;

import java.util.Set;

import org.apache.commons.collections4.MapIterator;

import org.apache.commons.collections4.MultiSet;

import org.apache.commons.collections4.MultiValuedMap;

import org.apache.commons.collections4.Unmodifiable;

import org.apache.commons.collections4.collection.UnmodifiableCollection;

import org.apache.commons.collections4.iterators.UnmodifiableMapIterator;

import org.apache.commons.collections4.map.UnmodifiableMap;

import org.apache.commons.collections4.multiset.UnmodifiableMultiSet;

import org.apache.commons.collections4.set.UnmodifiableSet;

/**

 * Decorates another {@link MultiValuedMap} to ensure it can't be altered.

 * <p>

 * Attempts to modify it will result in an UnsupportedOperationException.

 * </p>

 *

 * @param <K> the type of key elements

 * @param <V> the type of value elements

 *

 * @since 4.1

 */

public final class UnmodifiableMultiValuedMap<K, V>

        extends AbstractMultiValuedMapDecorator<K, V> implements Unmodifiable {

    /** Serialization version */

    private static final long serialVersionUID = 20150612L;

    /**

     * Factory method to create an unmodifiable MultiValuedMap.

     * <p>

     * If the map passed in is already unmodifiable, it is returned.

     *

     * @param <K> the type of key elements

     * @param <V> the type of value elements

     * @param map  the map to decorate, may not be null

     * @return an unmodifiable MultiValuedMap

     * @throws NullPointerException if map is null

     */

    @SuppressWarnings("unchecked")

    public static <K, V> UnmodifiableMultiValuedMap<K, V> unmodifiableMultiValuedMap(

            final MultiValuedMap<? extends K, ? extends V> map) {

        if (map instanceof Unmodifiable) {

            return (UnmodifiableMultiValuedMap<K, V>) map;

        }

        return new UnmodifiableMultiValuedMap<>(map);

    }

    /**

     * Constructor that wraps (not copies).

     *

     * @param map  the MultiValuedMap to decorate, may not be null

     * @throws NullPointerException if the map is null

     */

    @SuppressWarnings("unchecked")

    private UnmodifiableMultiValuedMap(final MultiValuedMap<? extends K, ? extends V> map) {

        super((MultiValuedMap<K, V>) map);

    }

    @Override

    public Collection<V> remove(final Object key) {

        throw new UnsupportedOperationException();

    }

    @Override

    public boolean removeMapping(final Object key, final Object item) {

        throw new UnsupportedOperationException();

    }

    @Override

    public void clear() {

        throw new UnsupportedOperationException();

    }

    @Override

    public Collection<V> get(final K key) {

        return UnmodifiableCollection.unmodifiableCollection(decorated().get(key));

    }

    @Override

    public boolean put(final K key, final V value) {

        throw new UnsupportedOperationException();

    }

    @Override

    public Set<K> keySet() {

        return UnmodifiableSet.unmodifiableSet(decorated().keySet());

    }

    @Override

    public Collection<Entry<K, V>> entries() {

        return UnmodifiableCollection.unmodifiableCollection(decorated().entries());

    }

    @Override

    public MultiSet<K> keys() {

        return UnmodifiableMultiSet.unmodifiableMultiSet(decorated().keys());

    }

    @Override

    public Collection<V> values() {

        return UnmodifiableCollection.unmodifiableCollection(decorated().values());

    }

    @Override

    public Map<K, Collection<V>> asMap() {

        return UnmodifiableMap.unmodifiableMap(decorated().asMap());

    }

    @Override

    public MapIterator<K, V> mapIterator() {

        return UnmodifiableMapIterator.unmodifiableMapIterator(decorated().mapIterator());

    }

    @Override

    public boolean putAll(final K key, final Iterable<? extends V> values) {

        throw new UnsupportedOperationException();

    }

    @Override

    public boolean putAll(final Map<? extends K, ? extends V> map) {

        throw new UnsupportedOperationException();

    }

    @Override

    public boolean putAll(final MultiValuedMap<? extends K, ? extends V> map) {

        throw new UnsupportedOperationException();

    }

}