Java event after two keyEvents

Question

I am programming a game and need to execute two keyEvents before fire();

For now I have done this to test:

if (key == KeyEvent.VK_SPACE) {
    fire();
}

What I need is:

if (key == KeyEvent.VK_DOWN) && (key == KeyEvent.VK_UP) {
    fire();
}

The problem is, they need to be pressed in this sequence: First down, then up and so fire, but I don't know how can I do it.

Answer 1

I think the best way to do it is to implement a KeyListener (an example is here) in order to recognize exactly which event has occurred. For example you could use a boolean variable (i.e. readyToFire) to store whether the

 `KeyEvent.VK_UP`

event produces or not a fire one. For instance a possible implementation may be:

    //boolean readyToFire = false;

    public void keyTyped(KeyEvent e) {
         if(e == KeyEvent.VK_UP && readyToFire){
              fire();
         }
    }

    public void keyPressed(KeyEvent e) {
         if(e == KeyEvent.VK_DOWN){
              readyToFire = true;
         }
         else if(e == KeyEvent.VK_UP && readyToFire){
              fire();
         }
    }

    public void keyReleased(KeyEvent e) {
         if(e == KeyEvent.VK_DOWN){
              readyToFire = false;
         }
    }

Answer 2

Keep track of time and key pressed for last 4 events in a FIFO, and see the history to decide