Understanding Abstract Classes and Interfaces - Java Programming: Comprehensive Concepts and Techniques - page 662

To Implement the Activator Interface

1. Start TextPad and open the file, LogonFrame.java, from the Chapter10
folder on the Data Disk. Replace lines 1 through 16 as shown in
Figure 10-49 on page 657. In the comments, insert your own name as
programmer and enter the current date.
TextPad displays code for the initial comments, class header, instance
variables, and constructor header for the LogonFrame class (Figure 10-50).
The LogonFrame class implements both the ActionListener and the Activator
interfaces.

LogonFrame.java

LogonFrame.java

replaced lines

implements multiple
interfaces

instance
variables

FIGURE 10-50

2. Replace lines 160 through 174 as shown in Figure 10-49.

TextPad displays code for the method, doStockActivity(), and the callback
method, activate() (Figure 10-51). The keyword, this, is used to indicate
that a reference to the current object is passed to a new StockFrame object.

this reference passed to
new StockFrame object

hides LogonFrame window

displays StockFrame
window

replaced lines

callback method, activate()
makes LogonFrame visible

FIGURE 10-51