get, set, add, and
* remove) atop the list iterator, opposite of AbstractList's
* approach of implementing the iterator atop random access.
*
*
* To implement a list, you need an implementation for size()
* and listIterator. With just hasNext,
* next, hasPrevious, previous,
* nextIndex, and previousIndex, you have an
* unmodifiable list. For a modifiable one, add set, and for
* a variable-size list, add add and remove.
*
*
* The programmer should provide a no-argument constructor, and one that
* accepts another Collection, as recommended by the Collection interface.
* Unfortunately, there is no way to enforce this in Java.
*
* @author Original author unknown
* @author Bryce McKinlay
* @author Eric Blake
*
* This implementation grabs listIterator(index), then proceeds to use add
* for each element returned by c's iterator. Sun's online specs are wrong,
* claiming that this also calls next(): listIterator.add() correctly
* skips the added element.
*
* @param index the location to insert the collection
* @param c the collection to insert
* @return true if the list was modified by this action, that is, if c is
* non-empty
* @throws UnsupportedOperationException if this list does not support the
* addAll operation
* @throws IndexOutOfBoundsException if index < 0 || index > size()
* @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
* @see #add(int, Object)
*/
public boolean addAll(int index, Collection c)
{
Iterator ci = c.iterator();
int size = c.size();
ListIterator i = listIterator(index);
for (int pos = size; pos > 0; pos--)
i.add(ci.next());
return size > 0;
}
/**
* Get the element at a given index in this list. This implementation
* returns listIterator(index).next().
*
* @param index the index of the element to be returned
* @return the element at index index in this list
* @throws IndexOutOfBoundsException if index < 0 || index >= size()
*/
public Object get(int index)
{
// This is a legal listIterator position, but an illegal get.
if (index == size())
throw new IndexOutOfBoundsException("Index: " + index + ", Size:"
+ size());
return listIterator(index).next();
}
/**
* Obtain an Iterator over this list, whose sequence is the list order. This
* implementation returns listIterator().
*
* @return an Iterator over the elements of this list, in order
*/
public Iterator iterator()
{
return listIterator();
}
/**
* Remove the element at a given position in this list (optional operation).
* Shifts all remaining elements to the left to fill the gap. This
* implementation uses listIterator(index) and ListIterator.remove().
*
* @param index the position within the list of the object to remove
* @return the object that was removed
* @throws UnsupportedOperationException if this list does not support the
* remove operation
* @throws IndexOutOfBoundsException if index < 0 || index >= size()
*/
public Object remove(int index)
{
// This is a legal listIterator position, but an illegal remove.
if (index == size())
throw new IndexOutOfBoundsException("Index: " + index + ", Size:"
+ size());
ListIterator i = listIterator(index);
Object removed = i.next();
i.remove();
return removed;
}
/**
* Replace an element of this list with another object (optional operation).
* This implementation uses listIterator(index) and ListIterator.set(o).
*
* @param index the position within this list of the element to be replaced
* @param o the object to replace it with
* @return the object that was replaced
* @throws UnsupportedOperationException if this list does not support the
* set operation
* @throws IndexOutOfBoundsException if index < 0 || index >= size()
* @throws ClassCastException if o cannot be added to this list due to its
* type
* @throws IllegalArgumentException if o cannot be added to this list for
* some other reason
*/
public Object set(int index, Object o)
{
// This is a legal listIterator position, but an illegal set.
if (index == size())
throw new IndexOutOfBoundsException("Index: " + index + ", Size:"
+ size());
ListIterator i = listIterator(index);
Object old = i.next();
i.set(o);
return old;
}
}