/*
    * 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.trie;
  
  import java.io.Serializable;
  import java.util.Collection;
  import java.util.Collections;
  import java.util.Comparator;
  import java.util.Map;
  import java.util.Objects;
  import java.util.Set;
  import java.util.SortedMap;
  
  import org.apache.commons.collections4.OrderedMapIterator;
  import org.apache.commons.collections4.Trie;
  import org.apache.commons.collections4.Unmodifiable;
  import org.apache.commons.collections4.iterators.UnmodifiableOrderedMapIterator;
  
  /**
   * An unmodifiable {@link Trie}.
   *
   * @param <K> the type of the keys in this map
   * @param <V> the type of the values in this map
   * @since 4.0
   */
  public class UnmodifiableTrie<K, V> implements Trie<K, V>, Serializable, Unmodifiable {
  
      /** Serialization version */
      private static final long serialVersionUID = -7156426030315945159L;
  
      /**
       * Factory method to create an unmodifiable trie.
       *
       * @param <K>  the key type
       * @param <V>  the value type
       * @param trie  the trie to decorate, must not be null
       * @return a new unmodifiable trie
       * @throws NullPointerException if trie is null
       */
      public static <K, V> Trie<K, V> unmodifiableTrie(final Trie<K, ? extends V> trie) {
          if (trie instanceof Unmodifiable) {
              @SuppressWarnings("unchecked") // safe to upcast
              final Trie<K, V> tmpTrie = (Trie<K, V>) trie;
              return tmpTrie;
          }
          return new UnmodifiableTrie<>(trie);
      }
  
      private final Trie<K, V> delegate;
  
      /**
       * Constructor that wraps (not copies).
       *
       * @param trie  the trie to decorate, must not be null
       * @throws NullPointerException if trie is null
       */
      public UnmodifiableTrie(final Trie<K, ? extends V> trie) {
          @SuppressWarnings("unchecked") // safe to upcast
          final Trie<K, V> tmpTrie = (Trie<K, V>) Objects.requireNonNull(trie, "trie");
          this.delegate = tmpTrie;
      }
  
      @Override
      public void clear() {
          throw new UnsupportedOperationException();
      }
  
      @Override
      public Comparator<? super K> comparator() {
          return delegate.comparator();
      }
  
      @Override
      public boolean containsKey(final Object key) {
          return delegate.containsKey(key);
      }
  
      @Override
      public boolean containsValue(final Object value) {
          return delegate.containsValue(value);
      }
  
      @Override
      public Set<Entry<K, V>> entrySet() {
          return Collections.unmodifiableSet(delegate.entrySet());
     }
 
     @Override
     public boolean equals(final Object obj) {
         return delegate.equals(obj);
     }
 
     @Override
     public K firstKey() {
         return delegate.firstKey();
     }
 
     @Override
     public V get(final Object key) {
         return delegate.get(key);
     }
 
     @Override
     public int hashCode() {
         return delegate.hashCode();
     }
 
     @Override
     public SortedMap<K, V> headMap(final K toKey) {
         return Collections.unmodifiableSortedMap(delegate.headMap(toKey));
     }
 
     @Override
     public boolean isEmpty() {
         return delegate.isEmpty();
     }
 
     @Override
     public Set<K> keySet() {
         return Collections.unmodifiableSet(delegate.keySet());
     }
 
     @Override
     public K lastKey() {
         return delegate.lastKey();
     }
 
     @Override
     public OrderedMapIterator<K, V> mapIterator() {
         final OrderedMapIterator<K, V> it = delegate.mapIterator();
         return UnmodifiableOrderedMapIterator.unmodifiableOrderedMapIterator(it);
     }
 
     @Override
     public K nextKey(final K key) {
         return delegate.nextKey(key);
     }
 
     @Override
     public SortedMap<K, V> prefixMap(final K key) {
         return Collections.unmodifiableSortedMap(delegate.prefixMap(key));
     }
 
     @Override
     public K previousKey(final K key) {
         return delegate.previousKey(key);
     }
 
     @Override
     public V put(final K key, final V value) {
         throw new UnsupportedOperationException();
     }
 
     @Override
     public void putAll(final Map<? extends K, ? extends V> m) {
         throw new UnsupportedOperationException();
     }
 
     @Override
     public V remove(final Object key) {
         throw new UnsupportedOperationException();
     }
 
     @Override
     public int size() {
         return delegate.size();
     }
 
     @Override
     public SortedMap<K, V> subMap(final K fromKey, final K toKey) {
         return Collections.unmodifiableSortedMap(delegate.subMap(fromKey, toKey));
     }
 
     @Override
     public SortedMap<K, V> tailMap(final K fromKey) {
         return Collections.unmodifiableSortedMap(delegate.tailMap(fromKey));
     }
 
     @Override
     public String toString() {
         return delegate.toString();
     }
 
     @Override
     public Collection<V> values() {
         return Collections.unmodifiableCollection(delegate.values());
     }
 
 }