Java™ Application Development on Linux - Dator

394Chapter 17Other Ways: Alternatives to SwingExample 17.2 The upton Button event listener class reference declarationprivate SelectionListener upAction = new SelectionAdapter(){public void widgetSelected(SelectionEvent e){// this is the action for UP arrow icon;Account next;next = current.getParent();if (next != null) {current = next;setStatus();}}} ;17.3.4 Completing the Conversion of the BudgetPro ClassTo keep this book to a reasonable size, we are always trying to avoid coveringthe same ground more than once. We won’t walk you through the details ofconverting the createList() and createButtons() methods as we did withthe createStatus() method, but we will talk about the details of convertingto SWT of some of the classes used in those methods.17.3.4.1 The Table, TableColumn, and TableItem ClassesWithout a doubt, the biggest change the BudgetPro class requires in order toconvert from Swing to SWT lies in the table pane of the UI. The Table classis the root of tables in SWT. The TableColumn class defines the names andheaders of the columns. TableColumn constructors must have a Table as theirfirst argument, followed, as usual, by a numeric style specification. TheTableItem class defines a row in the Table. As with TableColumn, theTableItem constructor must have a Table as its first argument, followed bya numeric style.If you think about it, this is an extension of the same design philosophythat requires that all constructors name their parent Composite. While Swing’sabstract table model permits a nice separation between the data and the presentation,implementing a similar system in SWT would violate its strict containersemantics.You will need to follow the basic rewrite process outlined above and youwill have to squish the Swing abstract table model into the simpler SWT table