Concept

More on the System Browser

Class Categories and Classes

The top left pane is for the Class Categories. This categories have nothing to do with inheritance. If you want to look at the classes from purely an inheritance perspective then use the class hierarchy browser. Which looks/works just like the system browser does only the it only has three top panes instead of four (i.e. no categories).

Classes are entered into class categories. Therefore, by default the large text entry pane at the bottom of the Browser is filled wit h a generic object declaration template whenever you select a category. Middle mousing in the Class Category pane will allow you to preform operation on Class Categories. (e.g. file-out every in a class category, remove a class category, add a new category, etc.)

Next to the Class Cataloger pane is the Class pane. All the classes in that category will appear here. Selecting a Class will cause the class definition to appear in the large text pane at the bottom of the browser. Middle mousing will allow you to preform a variety of operations on Classes.

Immediately below the Class pane is the instance/class button pair. This affects the two right panes of the Browser window. By pressing the instance button you can preform operations on the instance methods of the selected class. By pressing the class button you can preform operations on the class methods. Instance methods operate on instantiations of the class. Class methods operate on the object that represents the class.

Method Categories and Methods

The right two panes of the Browser window have to do with methods. Like class categories, method categories are very useful for organizing your methods into groups. All the methods in a given category preform a generic behavior that is similar to one another.

[HINT: create a sheet of paper that lists the method categories, for class and instance, and keep this with you when you are written Smalltalk code and designing. In the latter situation is it useful since it helps you ask questions about the completeness of your OOD. For instance, for every object you create you should ask yourself have I handled/specified/dealt with the initialize-release and/or instance-creation services? see page 17-18 of Coad & Nicola. These categories have evolved over the history of Smalltalk so they probably have strong OO foundations, n'est pas?]

Methods are entered into categories. Therefore, by default the large text entry pane at the bottom of the Browser is filled with a generic method declaration template whenever you select a category. Middle mousing in the Method Category pane will allow you to preform operations on method categories.

The far right pane is for methods. Selecting a method in this pane will present the method's definition. Middle mousing in this pane will allow you to preform operations on methods.... as you might have guessed by now.

References to this concept: