Object Orientation (OO) in GUIs

Tue, 08 Jan 2008 21:44:00 GMT

I was taught (hopefully rightly) that a class contains data relevant to it and methods which act on that data. For example, a class representing a Monkey might have attributes like date of birth, male/female, number of children, and a reference to the zoo where it lives. Methods might be getYearsOld() to work out how many days old it is, haveSex(List<Monkey> partners) [aren't chimps well known for group sex?], addChild(Monkey kid), setZoo(Zoo newHome).

Equally a complex graphical user interface component like a tree or a table might contain a matrix or hierarchy of cells and methods for setting the cells attributes (data, size, borders, rendering information, etc). It would typically have renderers for painting the cells as well as perhaps editors for editing the data in the cells. In fact, Swing has a rather nice implementation of Tables, Trees and even Tree-Tables. Eclipse JFace is fast catching up.

So if you do find yourself building something like this, say in Java Script, look at the nearest thing you can find that already exists, analyse how object oriented it is, then implement something similar (even sub-class it).

What you want to avoid is creating a load of helper methods which just build the GUI in a totally pre-object-oriented manner - Builder Classes as I call them.

I have seen this done several times by programmers that learned to program in the object oriented age. It might be expected from an older programmer who learned to program pre-object orientation, or one that has never used an object oriented language. But its odd when its done by programmers selling themselves as knowing object orientation. Very odd indeed.

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The Kitchen in the Zoo - oo tag

Object Orientation (OO) in GUIs