/*
    * 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
    *
    *      https://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.map;
  
  import java.io.IOException;
  import java.io.ObjectInputStream;
  import java.io.ObjectOutputStream;
  import java.io.Serializable;
  import java.util.Collection;
  import java.util.Comparator;
  import java.util.Map;
  import java.util.Set;
  import java.util.SortedMap;
  
  import org.apache.commons.collections4.Unmodifiable;
  import org.apache.commons.collections4.collection.UnmodifiableCollection;
  import org.apache.commons.collections4.set.UnmodifiableSet;
  
  /**
   * Decorates another {@code SortedMap} to ensure it can't be altered.
   * <p>
   * This class is Serializable from Commons Collections 3.1.
   * </p>
   * <p>
   * Attempts to modify it will result in an UnsupportedOperationException.
   * </p>
   *
   * @param <K> The type of the keys in this map
   * @param <V> The type of the values in this map
   * @since 3.0
   */
  public final class UnmodifiableSortedMap<K, V>
          extends AbstractSortedMapDecorator<K, V>
          implements Unmodifiable, Serializable {
  
      /** Serialization version */
      private static final long serialVersionUID = 5805344239827376360L;
  
      /**
       * Factory method to create an unmodifiable sorted map.
       *
       * @param <K>  the key type
       * @param <V>  the value type
       * @param map  The map to decorate, must not be null
       * @return A new unmodifiable sorted map
       * @throws NullPointerException if map is null
       * @since 4.0
       */
      public static <K, V> SortedMap<K, V> unmodifiableSortedMap(final SortedMap<K, ? extends V> map) {
          if (map instanceof Unmodifiable) {
              @SuppressWarnings("unchecked") // safe to upcast
              final SortedMap<K, V> tmpMap = (SortedMap<K, V>) map;
              return tmpMap;
          }
          return new UnmodifiableSortedMap<>(map);
      }
  
      /**
       * Constructor that wraps (not copies).
       *
       * @param map  The map to decorate, must not be null
       * @throws NullPointerException if map is null
       */
      @SuppressWarnings("unchecked") // safe to upcast
      private UnmodifiableSortedMap(final SortedMap<K, ? extends V> map) {
          super((SortedMap<K, V>) map);
      }
  
      /**
       * Always throws {@link UnsupportedOperationException}.
       *
       * @throws UnsupportedOperationException Always thrown.
       */
      @Override
      public void clear() {
          throw new UnsupportedOperationException();
      }
  
      @Override
      public Comparator<? super K> comparator() {
          return decorated().comparator();
      }
  
      @Override
      public Set<Map.Entry<K, V>> entrySet() {
         return UnmodifiableEntrySet.unmodifiableEntrySet(super.entrySet());
     }
 
     @Override
     public K firstKey() {
         return decorated().firstKey();
     }
 
     @Override
     public SortedMap<K, V> headMap(final K toKey) {
         return new UnmodifiableSortedMap<>(decorated().headMap(toKey));
     }
 
     @Override
     public Set<K> keySet() {
         return UnmodifiableSet.unmodifiableSet(super.keySet());
     }
 
     @Override
     public K lastKey() {
         return decorated().lastKey();
     }
 
     /**
      * Always throws {@link UnsupportedOperationException}.
      *
      * @param key Ignored.
      * @param value Ignored.
      * @throws UnsupportedOperationException Always thrown.
      */
     @Override
     public V put(final K key, final V value) {
         throw new UnsupportedOperationException();
     }
 
     /**
      * Always throws {@link UnsupportedOperationException}.
      *
      * @param mapToCopy Ignored.
      * @throws UnsupportedOperationException Always thrown.
      */
     @Override
     public void putAll(final Map<? extends K, ? extends V> mapToCopy) {
         throw new UnsupportedOperationException();
     }
 
     /**
      * Deserializes the map in using a custom routine.
      *
      * @param in  The input stream
      * @throws IOException Thrown if an error occurs while reading from the stream
      * @throws ClassNotFoundException if an object read from the stream cannot be loaded
      * @since 3.1
      */
     @SuppressWarnings("unchecked")
     private void readObject(final ObjectInputStream in) throws IOException, ClassNotFoundException {
         in.defaultReadObject();
         map = (Map<K, V>) in.readObject();
     }
 
     /**
      * Always throws {@link UnsupportedOperationException}.
      *
      * @param key Ignored.
      * @throws UnsupportedOperationException Always thrown.
      */
     @Override
     public V remove(final Object key) {
         throw new UnsupportedOperationException();
     }
 
     @Override
     public SortedMap<K, V> subMap(final K fromKey, final K toKey) {
         return new UnmodifiableSortedMap<>(decorated().subMap(fromKey, toKey));
     }
 
     @Override
     public SortedMap<K, V> tailMap(final K fromKey) {
         return new UnmodifiableSortedMap<>(decorated().tailMap(fromKey));
     }
 
     @Override
     public Collection<V> values() {
         return UnmodifiableCollection.unmodifiableCollection(super.values());
     }
 
     /**
      * Serializes this object to an ObjectOutputStream.
      *
      * @param out The target ObjectOutputStream.
      * @throws IOException thrown when an I/O errors occur writing to the target stream.
      * @since 3.1
      */
     private void writeObject(final ObjectOutputStream out) throws IOException {
         out.defaultWriteObject();
         out.writeObject(map);
     }
 
 }