/*
    * Copyright (C) 2007 The Guava Authors
    *
    * Licensed 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 com.google.common.collect;
  
  import com.google.common.annotations.Beta;
  import com.google.common.annotations.GwtCompatible;
  
  import java.util.Collection;
  import java.util.Iterator;
  import java.util.List;
  import java.util.ListIterator;
  
  import javax.annotation.Nullable;
  
  /**
   * A list which forwards all its method calls to another list. Subclasses should
   * override one or more methods to modify the behavior of the backing list as
   * desired per the <a
   * href="http://en.wikipedia.org/wiki/Decorator_pattern">decorator pattern</a>.
   *
   * <p>This class does not implement {@link java.util.RandomAccess}. If the
   * delegate supports random access, the {@code ForwardingList} subclass should
   * implement the {@code RandomAccess} interface.
   *
   * <p><b>Warning:</b> The methods of {@code ForwardingList} forward
   * <b>indiscriminately</b> to the methods of the delegate. For example,
   * overriding {@link #add} alone <b>will not</b> change the behavior of {@link
   * #addAll}, which can lead to unexpected behavior. In this case, you should
   * override {@code addAll} as well, either providing your own implementation, or
   * delegating to the provided {@code standardAddAll} method.
   *
   * <p>The {@code standard} methods and any collection views they return are not
   * guaranteed to be thread-safe, even when all of the methods that they depend
   * on are thread-safe.
   *
   * @author Mike Bostock
   * @author Louis Wasserman
   * @since 2.0 (imported from Google Collections Library)
   */
  @GwtCompatible
  public abstract class ForwardingList<E> extends ForwardingCollection<E>
      implements List<E> {
    // TODO(user): identify places where thread safety is actually lost
  
    /** Constructor for use by subclasses. */
    protected ForwardingList() {}
  
    @Override protected abstract List<E> delegate();
  
    @Override
    public void add(int index, E element) {
      delegate().add(index, element);
    }
  
    @Override
    public boolean addAll(int index, Collection<? extends E> elements) {
      return delegate().addAll(index, elements);
    }
  
    @Override
    public E get(int index) {
      return delegate().get(index);
    }
  
    @Override
    public int indexOf(Object element) {
      return delegate().indexOf(element);
    }
  
    @Override
    public int lastIndexOf(Object element) {
      return delegate().lastIndexOf(element);
    }
  
    @Override
    public ListIterator<E> listIterator() {
      return delegate().listIterator();
    }
  
    @Override
    public ListIterator<E> listIterator(int index) {
      return delegate().listIterator(index);
    }
  
    @Override
   public E remove(int index) {
     return delegate().remove(index);
   }
 
   @Override
   public E set(int index, E element) {
     return delegate().set(index, element);
   }
 
   @Override
   public List<E> subList(int fromIndex, int toIndex) {
     return delegate().subList(fromIndex, toIndex);
   }
 
   @Override public boolean equals(@Nullable Object object) {
     return object == this || delegate().equals(object);
   }
 
   @Override public int hashCode() {
     return delegate().hashCode();
   }
 
   /**
    * A sensible default implementation of {@link #add(Object)}, in terms of
    * {@link #add(int, Object)}. If you override {@link #add(int, Object)}, you
    * may wish to override {@link #add(Object)} to forward to this
    * implementation.
    *
    * @since 7.0
    */
   protected boolean standardAdd(E element) {
     add(size(), element);
     return true;
   }
 
   /**
    * A sensible default implementation of {@link #addAll(int, Collection)}, in
    * terms of the {@code add} method of {@link #listIterator(int)}. If you
    * override {@link #listIterator(int)}, you may wish to override {@link
    * #addAll(int, Collection)} to forward to this implementation.
    *
    * @since 7.0
    */
   protected boolean standardAddAll(
       int index, Iterable<? extends E> elements) {
     return Lists.addAllImpl(this, index, elements);
   }
 
   /**
    * A sensible default implementation of {@link #indexOf}, in terms of {@link
    * #listIterator()}. If you override {@link #listIterator()}, you may wish to
    * override {@link #indexOf} to forward to this implementation.
    *
    * @since 7.0
    */
   protected int standardIndexOf(@Nullable Object element) {
     return Lists.indexOfImpl(this, element);
   }
 
   /**
    * A sensible default implementation of {@link #lastIndexOf}, in terms of
    * {@link #listIterator(int)}. If you override {@link #listIterator(int)}, you
    * may wish to override {@link #lastIndexOf} to forward to this
    * implementation.
    *
    * @since 7.0
    */
   protected int standardLastIndexOf(@Nullable Object element) {
     return Lists.lastIndexOfImpl(this, element);
   }
 
   /**
    * A sensible default implementation of {@link #iterator}, in terms of
    * {@link #listIterator()}. If you override {@link #listIterator()}, you may
    * wish to override {@link #iterator} to forward to this implementation.
    *
    * @since 7.0
    */
   protected Iterator<E> standardIterator() {
     return listIterator();
   }
 
   /**
    * A sensible default implementation of {@link #listIterator()}, in terms of
    * {@link #listIterator(int)}. If you override {@link #listIterator(int)}, you
    * may wish to override {@link #listIterator()} to forward to this
    * implementation.
    *
    * @since 7.0
    */
   protected ListIterator<E> standardListIterator() {
     return listIterator(0);
   }
 
   /**
    * A sensible default implementation of {@link #listIterator(int)}, in terms
    * of {@link #size}, {@link #get(int)}, {@link #set(int, Object)}, {@link
    * #add(int, Object)}, and {@link #remove(int)}. If you override any of these
    * methods, you may wish to override {@link #listIterator(int)} to forward to
    * this implementation.
    *
    * @since 7.0
    */
   @Beta protected ListIterator<E> standardListIterator(int start) {
     return Lists.listIteratorImpl(this, start);
   }
 
   /**
    * A sensible default implementation of {@link #subList(int, int)}. If you
    * override any other methods, you may wish to override {@link #subList(int,
    * int)} to forward to this implementation.
    *
    * @since 7.0
    */
   @Beta protected List<E> standardSubList(int fromIndex, int toIndex) {
     return Lists.subListImpl(this, fromIndex, toIndex);
   }
 
   /**
    * A sensible definition of {@link #equals(Object)} in terms of {@link #size}
    * and {@link #iterator}. If you override either of those methods, you may
    * wish to override {@link #equals(Object)} to forward to this implementation.
    *
    * @since 7.0
    */
   @Beta protected boolean standardEquals(@Nullable Object object) {
     return Lists.equalsImpl(this, object);
   }
 
   /**
    * A sensible definition of {@link #hashCode} in terms of {@link #iterator}.
    * If you override {@link #iterator}, you may wish to override {@link
    * #hashCode} to forward to this implementation.
    *
    * @since 7.0
    */
   @Beta protected int standardHashCode() {
     return Lists.hashCodeImpl(this);
   }
 }