protected boolean doAddAll(int index, IList<? extends E> list) {
		int listSize = list.size();
		doEnsureCapacity(size() + listSize);

		if (listSize == 0) {
			return false;
		}

		boolean changed = false;
		int prevSize = size();
		for (int i=0; i<listSize; i++) {
			E elem = list.get(i);
			if (doAdd(index, elem)) {
				changed = true;
				if (index != -1) {
					if (prevSize != size()) {
						prevSize = size();
						index++;
					}
				}
			}
		}
		return changed;
	}
Helper method for adding multiple elements to the list.
This default implementation calls doAdd() for adding each element.

@param index index where element should be added
             (-1 is valid for adding at the end)
@return      true if elements have been added, false otherwise
jphp-runtime/src/php/runtime/memory/support/IList.java