Sams Teach Yourself Java™ in 24 Hours, Sixth Edition

Baking a Pie Graph

To draw this hour to a close, you create PiePanel, a GUI component that displays a pie graph. This component is a subclass of JPanel, a simple Swing container that’s useful as a place to draw something.

One way to begin creating a class is to define the way objects of the class are created. Programs that use the PiePanel class must undertake the following steps:

• Create a PiePanel object by using the constructor method PiePanel(int). The integer specified as an argument is the number of slices the pie graph contains.

• Call the object’s addSlice(Color, float) method to give a slice the designated color and value.

The value of each slice in PiePanel is the quantity represented by that slice.

For example, Table 23.1 displays ...