bigBang method.
*/
public World(){ }
/////////////////////////////////////////////////////////////////////////
// Methods for interacting with the World //
/////////////////////////////////////////////////////////////////////////
/**
* Start the world by creating a canvas of the given size, creating
* and adding the key and mouse adapters, and starting the timer at the
* given speed.
*
* @param w the width of the {@link Canvas Canvas}
* @param h the height of the {@link Canvas Canvas}
* @param speed the speed at which the clock runs
*/
public void bigBang(int w, int h, double speed){
// throw runtime exceptions if w, h <= 0
this.theCanvas = new Canvas(w, h);
this.worldExists = true;
// add the key listener to the frame for our canvas
this.ka = new MyKeyAdapter(this);
this.theCanvas.f.addKeyListener(ka);
// make sure the canvas responds to events
this.theCanvas.f.setFocusable(true);
// add the timer -- start it if speed is greater than 0
mytime = new MyTimer(this, speed);
if (speed > 0.0)
mytime.timer.start();
// finally, show the canvas and draw the inital world
this.theCanvas.show();
this.drawWorld();
}
/**
* Stop the timer, disable event processing - leave the canvas open,
* write the end of time message onto the canvas
*/
public void endOfTime(String s){
// remove listeners and set worldExists to false
mytime.timer.stop();
this.worldExists = false;
this.theCanvas.f.removeKeyListener(this.ka);
System.out.println("The world stopped: " + s);
// draw the final scene of the world with the end of time message
this.theCanvas.clear();
this.draw();
this.theCanvas.drawString(new Posn(10, 20),s);
}
/**
* End the world interactions - leave the canvas open,
* write the end of world message onto the canvas
*/
public void endOfWorld(String s){
// remove listeners and set worldExists to false
mytime.timer.stop();
this.worldExists = false;
this.theCanvas.f.removeKeyListener(this.ka);
System.out.println("The end of the world: " + s);
// draw the final scene of the world with the end of world message
this.theCanvas.clear();
this.draw();
this.theCanvas.drawString(new Posn(10, 20),s);
}
/**
* The method invoked by the timer on each tick.
* Delegates to the user to define a new state of the world,
* then resets the canvas and event handlers for the new world
* to those currently used.
*
* @return {@link World World} after the tick event
*/
protected void processTick(){
try{
if (worldExists){
this.onTick();
this.drawWorld();
}
}
catch(RuntimeException re){
re.printStackTrace();
endOfTime(re.getMessage());
//throw re;
Runtime.getRuntime().halt(1);
}
}
/**
* User defined method to be invoked by the timer on each tick.
* Update the {@link World World}.
Override this method in the game world class
*/ abstract public void onTick(); /** * The method invoked by the key adapter on selected key events. * Delegates to the user to define a new state of the world, * then resets the canvas and event handlers for the new world * to those currently used. * * @return{@link World World} after the key event
*/
protected void processKeyEvent(String ke){
try{
if (worldExists){
this.onKeyEvent(ke);
this.drawWorld();
}
}
catch(RuntimeException re){
re.printStackTrace();
endOfTime(re.getMessage());
//throw re;
Runtime.getRuntime().halt(1);
}
}
/**
* User defined method to be invoked by the key adapter
* on selected key events.
* Update the {@link World World}.
Override this method in the game world class
*/ abstract public void onKeyEvent(String s); /** * Invoke the user defineddraw method, if this
* {@link World World} has been initialized
* via bigBang and did not stop or end
* via endOfTime
* or endOfWorld
*
* @return true
*/
protected void drawWorld(){
if (this.worldExists){
this.theCanvas.clear();
this.draw();
}
}
/**
* User defined method to draw the {@link World World}.
Override this method in the game world class
*/ abstract public void draw(); } /** * The action listener for the timer events. * * @author Viera K. Proulx * @since August 2, 2007 */ class MyTimer{ /** the current{@link World World}
* that handles the timer events */
protected World currentWorld;
/** the Timer that generates the time events */
protected Timer timer;
public boolean running = true;
/** the timer speed */
protected int speed;
/**
* Create the initial timer for the given
* {@link World World} at the given speed.
*
* @param currentWorld the given {@link World World}
* @param speed the given speed
*/
protected MyTimer(World currentWorld, double speed){
this.currentWorld = currentWorld;
this.timer = new Timer((new Double(speed * 1000)).intValue(),
this.timerTasks);
this.speed = (new Double(speed * 1000)).intValue();
}
/**
* The callback for the timer events
*/
protected ActionListener timerTasks = new ActionListener() {
public void actionPerformed(ActionEvent evt) {
if (running)
currentWorld.processTick();
}
};
/**
* A helper method to convert the speed given as
* a delay time into milliseconds
*/
protected void setSpeed(){
this.timer.setDelay(this.speed);
}
}
/**
* The implementation of callbacks for the key events.
*Report all regular key presses and the four arrow keys
*Ignore other key pressed events, key released events, * special keys, etc.
* * @author Viera K. Proulx * @since August 2, 2007 */ class MyKeyAdapter extends KeyAdapter { /** the current{@link World World}
* that handles the key events */
protected World currentWorld;
/** the KeyAdapter that handles the key events */
protected MyKeyAdapter(World currentWorld){
this.currentWorld = currentWorld;
}
/**
* The callback for the key events
*/
protected void keyEventCallback(String keyString){
currentWorld.processKeyEvent(keyString);
}
// --------------------------------------------------------------------//
// the key event handlers //
// --------------------------------------------------------------------//-
/**
* Handle the key typed event from the canvas.
*This is where we get the letter keys.
* * @param e theKeyEvent that caused the callback
*/
public void keyTyped(KeyEvent e) {
displayInfo(e, "KEY TYPED: ");
}
/**
* Handle the key pressed event from the canvas.
*This is where we get the arrow keys.
* * @param e theKeyEvent that caused the callback
*/
public void keyPressed(KeyEvent e) {
displayInfo(e, "KEY PRESSED: ");
}
/**
* The key event major processor. The code is adopted from the code * provided by the Java documentation for key event processing.
* *We have to jump through some hoops to avoid * trying to print non-printing characters * such as Shift. (Not only do they not print, * but if you put them in a String, the characters * afterward won't show up in the text area.)
* *There may be unneeded code here. An earlier comment stated:
* needs to add conversion table from code to
* String. The code for converting a single character
* to String is included here.