Controlling Your Action Figure: Implementing Java Event Handlers and Using Lambda Expressions - Beginning Java 8 Games Development - page 299

Processing Your KeyEvent: Using the Switch-Case
Statement
KeyEvent object processing is a perfect application for implementing Java's highly ef-
ficient switch-case statement. We can add a case statement for each type of KeyCode
constant that is contained inside of any KeyEvent (named event ) that is passed into the
.handle() method. A KeyCode can be extracted from a KeyEvent object using a
.getCode() method. This method is called on the KeyEvent object named event, inside
of the switch() evaluation area. Inside of the switch{} body, the case statements com-
pare themselves against this extracted KeyCode constant, and if there is a match, the
statements after the colon are processed. The break; statement allows processing to exit
the switch-case evaluation, as an optimization.
This event handling switch-case structure should be implemented by using the fol-
lowing Java programming structure, which is also shown highlighted in Figure 9-10 :
scene .setOnKeyPressed (new EventHandler<KeyEvent>() {
@Override
public void handle(KeyEvent event ) {
switch ( event .getCode()) {
case UP: up = true; break;
case DOWN: down = true; break;
case LEFT: left = true; break;
case RIGHT: right = true; break;
}
}
});