Question

For example I can have something like so,

A
B
 ba
 bb
C
 Ca
D

Right Now I have a 2D array,but this isn’t very general, because I would need another dimension if I wanted to extend the maximum sublevel from 2 to 3. Any suggestions?

Answer 1

The Composite Pattern would be an appropriate application here:

(From wikipedia:) http://en.wikipedia.org/wiki/Composite_pattern

In your case:

• Create a base class called “Menu” (This corresponds to the Component part in the above diagram)
• Create a derived class called “MenuItem” (This corresponds to the Leaf part in the above diagram)
• Create a derived class called “SubMenu” (This corresponds to the Composite part in the above diagram) SubMenu can contain more Menu’s – which can be more MenuItem’s or SubMenu’s.

You can achieve desired ordering of menu elements based on their insertion order into a Composite “SubMenu” by implementing a counter with each SubMenu object: each time you call aSubMenu.add(newMenuItemOrSubMenu), aSubMenu should increment its own counter and tag the new item with the ordering number. (Exact detail of the implementation is up to you, you don’t have to use separate counter at all and just use a list or an array)