public void undo() {
switch (level) {
case Speaker.HIGH:
speaker.high();
break;
case Speaker.ON:
speaker.on();
break;
case Speaker.OFF:
speaker.off();
break;
case Speaker.LOW:
speaker.low();
break;
default:
speaker.off();
break;
}
}
public void execute() {
level = speaker.getlevel();
speaker.high();
}
