abstractlist.java

gcc的组建

     *
     * @param index the value to check
     * @throws IndexOutOfBoundsException if index < 0 || index >= size()
     */
    // This will get inlined, since it is private.
    private void checkBoundsExclusive(int index)
    {
      if (index < 0 || index >= size)
        throw new IndexOutOfBoundsException("Index: " + index + ", Size:"
                                            + size);
    }

    /**
     * Specified by AbstractList.subList to return the private field size.
     *
     * @return the sublist size
     * @throws ConcurrentModificationException if the backing list has been
     *         modified externally to this sublist
     */
    public int size()
    {
      checkMod();
      return size;
    }

    /**
     * Specified by AbstractList.subList to delegate to the backing list.
     *
     * @param index the location to modify
     * @param o the new value
     * @return the old value
     * @throws ConcurrentModificationException if the backing list has been
     *         modified externally to this sublist
     * @throws UnsupportedOperationException if the backing list does not
     *         support the set operation
     * @throws IndexOutOfBoundsException if index &lt; 0 || index &gt;= size()
     * @throws ClassCastException if o cannot be added to the backing list due
     *         to its type
     * @throws IllegalArgumentException if o cannot be added to the backing list
     *         for some other reason
     */
    public Object set(int index, Object o)
    {
      checkMod();
      checkBoundsExclusive(index);
      return backingList.set(index + offset, o);
    }

    /**
     * Specified by AbstractList.subList to delegate to the backing list.
     *
     * @param index the location to get from
     * @return the object at that location
     * @throws ConcurrentModificationException if the backing list has been
     *         modified externally to this sublist
     * @throws IndexOutOfBoundsException if index &lt; 0 || index &gt;= size()
     */
    public Object get(int index)
    {
      checkMod();
      checkBoundsExclusive(index);
      return backingList.get(index + offset);
    }

    /**
     * Specified by AbstractList.subList to delegate to the backing list.
     *
     * @param index the index to insert at
     * @param o the object to add
     * @throws ConcurrentModificationException if the backing list has been
     *         modified externally to this sublist
     * @throws IndexOutOfBoundsException if index &lt; 0 || index &gt; size()
     * @throws UnsupportedOperationException if the backing list does not
     *         support the add operation.
     * @throws ClassCastException if o cannot be added to the backing list due
     *         to its type.
     * @throws IllegalArgumentException if o cannot be added to the backing
     *         list for some other reason.
     */
    public void add(int index, Object o)
    {
      checkMod();
      checkBoundsInclusive(index);
      backingList.add(index + offset, o);
      size++;
      modCount = backingList.modCount;
    }

    /**
     * Specified by AbstractList.subList to delegate to the backing list.
     *
     * @param index the index to remove
     * @return the removed object
     * @throws ConcurrentModificationException if the backing list has been
     *         modified externally to this sublist
     * @throws IndexOutOfBoundsException if index &lt; 0 || index &gt;= size()
     * @throws UnsupportedOperationException if the backing list does not
     *         support the remove operation
     */
    public Object remove(int index)
    {
      checkMod();
      checkBoundsExclusive(index);
      Object o = backingList.remove(index + offset);
      size--;
      modCount = backingList.modCount;
      return o;
    }

    /**
     * Specified by AbstractList.subList to delegate to the backing list.
     * This does no bounds checking, as it assumes it will only be called
     * by trusted code like clear() which has already checked the bounds.
     *
     * @param fromIndex the lower bound, inclusive
     * @param toIndex the upper bound, exclusive
     * @throws ConcurrentModificationException if the backing list has been
     *         modified externally to this sublist
     * @throws UnsupportedOperationException if the backing list does
     *         not support removing elements.
     */
    protected void removeRange(int fromIndex, int toIndex)
    {
      checkMod();

      backingList.removeRange(offset + fromIndex, offset + toIndex);
      size -= toIndex - fromIndex;
      modCount = backingList.modCount;
    }

    /**
     * Specified by AbstractList.subList to delegate to the backing list.
     *
     * @param index the location to insert at
     * @param c the collection to insert
     * @return true if this list was modified, in other words, c is non-empty
     * @throws ConcurrentModificationException if the backing list has been
     *         modified externally to this sublist
     * @throws IndexOutOfBoundsException if index &lt; 0 || index &gt; size()
     * @throws UnsupportedOperationException if this list does not support the
     *         addAll operation
     * @throws ClassCastException if some element of c cannot be added to this
     *         list due to its type
     * @throws IllegalArgumentException if some element of c cannot be added
     *         to this list for some other reason
     * @throws NullPointerException if the specified collection is null
     */
    public boolean addAll(int index, Collection c)
    {
      checkMod();
      checkBoundsInclusive(index);
      int csize = c.size();
      boolean result = backingList.addAll(offset + index, c);
      size += csize;
      modCount = backingList.modCount;
      return result;
    }

    /**
     * Specified by AbstractList.subList to return addAll(size, c).
     *
     * @param c the collection to insert
     * @return true if this list was modified, in other words, c is non-empty
     * @throws ConcurrentModificationException if the backing list has been
     *         modified externally to this sublist
     * @throws UnsupportedOperationException if this list does not support the
     *         addAll operation
     * @throws ClassCastException if some element of c cannot be added to this
     *         list due to its type
     * @throws IllegalArgumentException if some element of c cannot be added
     *         to this list for some other reason
     * @throws NullPointerException if the specified collection is null
     */
    public boolean addAll(Collection c)
    {
      return addAll(size, c);
    }

    /**
     * Specified by AbstractList.subList to return listIterator().
     *
     * @return an iterator over the sublist
     */
    public Iterator iterator()
    {
      return listIterator();
    }

    /**
     * Specified by AbstractList.subList to return a wrapper around the
     * backing list's iterator.
     *
     * @param index the start location of the iterator
     * @return a list iterator over the sublist
     * @throws ConcurrentModificationException if the backing list has been
     *         modified externally to this sublist
     * @throws IndexOutOfBoundsException if the value is out of range
     */
    public ListIterator listIterator(final int index)
    {
      checkMod();
      checkBoundsInclusive(index);

      return new ListIterator()
      {
        private final ListIterator i = backingList.listIterator(index + offset);
        private int position = index;

        /**
         * Tests to see if there are any more objects to
         * return.
         *
         * @return True if the end of the list has not yet been
         *         reached.
         * @throws ConcurrentModificationException if the
         *         list has been modified elsewhere.
         */
        public boolean hasNext()
        {
          checkMod();
          return position < size;
        }

        /**
         * Tests to see if there are objects prior to the
         * current position in the list.
         *
         * @return True if objects exist prior to the current
         *         position of the iterator.
         * @throws ConcurrentModificationException if the
         *         list has been modified elsewhere.
         */
        public boolean hasPrevious()
        {
          checkMod();
          return position > 0;
        }

        /**
         * Retrieves the next object from the list.
         *
         * @return The next object.
         * @throws NoSuchElementException if there are no
         *         more objects to retrieve.
         * @throws ConcurrentModificationException if the
         *         list has been modified elsewhere.
         */
        public Object next()
        {
          if (position == size)
            throw new NoSuchElementException();
          position++;
          return i.next();
        }

        /**
         * Retrieves the previous object from the list.
         *
         * @return The next object.
         * @throws NoSuchElementException if there are no
         *         previous objects to retrieve.
         * @throws ConcurrentModificationException if the
         *         list has been modified elsewhere.
         */
        public Object previous()
        {
          if (position == 0)
            throw new NoSuchElementException();
          position--;
          return i.previous();
        }

        /**
         * Returns the index of the next element in the
         * list, which will be retrieved by <code>next()</code>
         *
         * @return The index of the next element.
         * @throws ConcurrentModificationException if the
         *         list has been modified elsewhere.
         */
        public int nextIndex()
        {
          return i.nextIndex() - offset;
        }

        /**
         * Returns the index of the previous element in the
         * list, which will be retrieved by <code>previous()</code>
         *
         * @return The index of the previous element.
         * @throws ConcurrentModificationException if the
         *         list has been modified elsewhere.
         */
        public int previousIndex()
        {
          return i.previousIndex() - offset;
        }

        /**
         * Removes the last object retrieved by <code>next()</code>
         * from the list, if the list supports object removal.
         *
         * @throws IllegalStateException if the iterator is positioned
         *         before the start of the list or the last object has already
         *         been removed.
         * @throws UnsupportedOperationException if the list does
         *         not support removing elements.
         */
        public void remove()
        {
          i.remove();
          size--;
          position = nextIndex();
          modCount = backingList.modCount;
        }


       /**
        * Replaces the last object retrieved by <code>next()</code>
        * or <code>previous</code> with o, if the list supports object
        * replacement and an add or remove operation has not already
        * been performed.
        *
        * @throws IllegalStateException if the iterator is positioned
        *         before the start of the list or the last object has already
        *         been removed.
        * @throws UnsupportedOperationException if the list doesn't support
        *         the addition or removal of elements.
        * @throws ClassCastException if the type of o is not a valid type
        *         for this list.
        * @throws IllegalArgumentException if something else related to o
        *         prevents its addition.
        * @throws ConcurrentModificationException if the list
        *         has been modified elsewhere.
        */
        public void set(Object o)
        {
          i.set(o);
        }

        /**
         * Adds the supplied object before the element that would be returned
         * by a call to <code>next()</code>, if the list supports addition.
         * 
         * @param o The object to add to the list.
         * @throws UnsupportedOperationException if the list doesn't support
         *         the addition of new elements.
         * @throws ClassCastException if the type of o is not a valid type
         *         for this list.
         * @throws IllegalArgumentException if something else related to o
         *         prevents its addition.
         * @throws ConcurrentModificationException if the list
         *         has been modified elsewhere.
         */
        public void add(Object o)
        {
          i.add(o);
          size++;
          position++;
          modCount = backingList.modCount;
        }

        // Here is the reason why the various modCount fields are mostly
        // ignored in this wrapper listIterator.
        // If the backing listIterator is failfast, then the following holds:
        //   Using any other method on this list will call a corresponding
        //   method on the backing list *after* the backing listIterator
        //   is created, which will in turn cause a ConcurrentModException
        //   when this listIterator comes to use the backing one. So it is
        //   implicitly failfast.
        // If the backing listIterator is NOT failfast, then the whole of
        //   this list isn't failfast, because the modCount field of the
        //   backing list is not valid. It would still be *possible* to
        //   make the iterator failfast wrt modifications of the sublist
        //   only, but somewhat pointless when the list can be changed under
        //   us.
        // Either way, no explicit handling of modCount is needed.
        // However modCount = backingList.modCount must be executed in add
        // and remove, and size must also be updated in these two methods,
        // since they do not go through the corresponding methods of the subList.
      };
    }
  } // class SubList

  /**
   * This class is a RandomAccess version of SubList, as required by
   * {@link AbstractList#subList(int, int)}.
   *
   * @author Eric Blake ([e-mail])
   */
  private static final class RandomAccessSubList extends SubList
    implements RandomAccess
  {
    /**
     * Construct the sublist.
     *
     * @param backing the list this comes from
     * @param fromIndex the lower bound, inclusive
     * @param toIndex the upper bound, exclusive
     */
    RandomAccessSubList(AbstractList backing, int fromIndex, int toIndex)
    {
      super(backing, fromIndex, toIndex);
    }
  } // class RandomAccessSubList

} // class AbstractList