哪位高手帮分析一下如下代码，研究了半天没搞明白，感谢

  public void add(int location, E object) {
        int size = lastIndex - firstIndex;
        if (0 < location && location < size) {
            if (firstIndex == 0 && lastIndex == array.length) {
                growForInsert(location, 1);
            } else if ((location < size / 2 && firstIndex > 0)
                    || lastIndex == array.length) {
                System.arraycopy(array, firstIndex, array, --firstIndex,
                        location);
            } else {
                int index = location + firstIndex;
                System.arraycopy(array, index, array, index + 1, size
                        - location);
                lastIndex++;
            }
            array[location + firstIndex] = object;
        } else if (location == 0) {
            if (firstIndex == 0) {
                growAtFront(1);
            }
            array[--firstIndex] = object;
        } else if (location == size) {
            if (lastIndex == array.length) {
                growAtEnd(1);
            }
            array[lastIndex++] = object;
        } else {
            throw new IndexOutOfBoundsException(Messages.getString("luni.0A",
                    location, lastIndex - firstIndex));
        }

        modCount++;
    }
--------------------编程问答-------------------- 能不能使用java代码格式输出呢?

补充：Java ,  Java EE