/*
    * 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.collections.list;
  
  import java.util.Collection;
  import java.util.Iterator;
  import java.util.List;
  import java.util.ListIterator;
  
  import org.apache.commons.collections.Unmodifiable;
  import org.apache.commons.collections.iterators.UnmodifiableIterator;
  import org.apache.commons.collections.iterators.UnmodifiableListIterator;
  
  /**
   * Decorates another <code>List</code> to ensure it can't be altered.
   * <p>
   * This class is Serializable from Commons Collections 3.1.
   * <p>
   * Attempts to modify it will result in an UnsupportedOperationException. 
   *
   * @since 3.0
   * @version $Id: UnmodifiableList.java 1429905 2013-01-07 17:15:14Z ggregory $
   */
  public final class UnmodifiableList<E>
          extends AbstractSerializableListDecorator<E>
          implements Unmodifiable {
  
      /** Serialization version */
      private static final long serialVersionUID = 6595182819922443652L;
  
      /**
       * Factory method to create an unmodifiable list.
       * 
       * @param <E> the type of the elements in the list
       * @param list  the list to decorate, must not be null
       * @return a new unmodifiable list
       * @throws IllegalArgumentException if list is null
       */
      public static <E> List<E> unmodifiableList(final List<E> list) {
          if (list instanceof Unmodifiable) {
              return list;
          }
          return new UnmodifiableList<E>(list);
      }
  
      //-----------------------------------------------------------------------
      /**
       * Constructor that wraps (not copies).
       * 
       * @param list  the list to decorate, must not be null
       * @throws IllegalArgumentException if list is null
       * @since Commons Collection 5
       */
      public UnmodifiableList(final List<E> list) {
          super(list);
      }
  
      //-----------------------------------------------------------------------
      @Override
      public Iterator<E> iterator() {
          return UnmodifiableIterator.unmodifiableIterator(decorated().iterator());
      }
  
      @Override
      public boolean add(final Object object) {
          throw new UnsupportedOperationException();
      }
  
      @Override
      public boolean addAll(final Collection<? extends E> coll) {
          throw new UnsupportedOperationException();
      }
  
      @Override
      public void clear() {
          throw new UnsupportedOperationException();
      }
  
      @Override
      public boolean remove(final Object object) {
          throw new UnsupportedOperationException();
      }
  
      @Override
      public boolean removeAll(final Collection<?> coll) {
         throw new UnsupportedOperationException();
     }
 
     @Override
     public boolean retainAll(final Collection<?> coll) {
         throw new UnsupportedOperationException();
     }
 
     //-----------------------------------------------------------------------
     @Override
     public ListIterator<E> listIterator() {
         return UnmodifiableListIterator.umodifiableListIterator(decorated().listIterator());
     }
 
     @Override
     public ListIterator<E> listIterator(final int index) {
         return UnmodifiableListIterator.umodifiableListIterator(decorated().listIterator(index));
     }
 
     @Override
     public void add(final int index, final E object) {
         throw new UnsupportedOperationException();
     }
 
     @Override
     public boolean addAll(final int index, final Collection<? extends E> coll) {
         throw new UnsupportedOperationException();
     }
 
     @Override
     public E remove(final int index) {
         throw new UnsupportedOperationException();
     }
 
     @Override
     public E set(final int index, final E object) {
         throw new UnsupportedOperationException();
     }
 
     @Override
     public List<E> subList(final int fromIndex, final int toIndex) {
         final List<E> sub = decorated().subList(fromIndex, toIndex);
         return new UnmodifiableList<E>(sub);
     }
 
 }