/*
    * 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 Map<K, Collection<V>> asMap() {
          return UnmodifiableMap.unmodifiableMap(decorated().asMap());
      }
  
      @Override
      public void clear() {
          throw new UnsupportedOperationException();
      }
  
      @Override
      public Collection<Entry<K, V>> entries() {
          return UnmodifiableCollection.unmodifiableCollection(decorated().entries());
      }
  
      @Override
      public Collection<V> get(final K key) {
          return UnmodifiableCollection.unmodifiableCollection(decorated().get(key));
     }
 
     @Override
     public MultiSet<K> keys() {
         return UnmodifiableMultiSet.unmodifiableMultiSet(decorated().keys());
     }
 
     @Override
     public Set<K> keySet() {
         return UnmodifiableSet.unmodifiableSet(decorated().keySet());
     }
 
     @Override
     public MapIterator<K, V> mapIterator() {
         return UnmodifiableMapIterator.unmodifiableMapIterator(decorated().mapIterator());
     }
 
     @Override
     public boolean put(final K key, final V value) {
         throw new UnsupportedOperationException();
     }
 
     @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();
     }
 
     @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 Collection<V> values() {
         return UnmodifiableCollection.unmodifiableCollection(decorated().values());
     }
 
 }