4,Simplified version of class Notification.
- By Andreas Backer
- November 15, 2000
JAVA PRIMER
JCommands: A Flexible Undo Framework for Java
Andreas Bäcker
Listing 4. Simplified version of class Notification.
public class Notification extends Command {
// The object that notifies its observers
private java.util.Observable observable;
// Messages being sent to observers
private Object applyArg, undoArg, redoArg;
public Notification(java.util.Observable o, int applyID, int undoID, Object ob) {
this.observable = o;
this.applyArg = new CmdArg1(applyID, ob);
this.undoArg = new CmdArg1(undoID, ob)
this.redoArg = this.applyArg;
}
public void apply() {
observable.notifyObservers(applyArg);
}
public void undo() {
observable.notifyObservers(undoArg);
}
}