add TankExplosion#destroyHook

SpecRunner.html

@@ -45,6 +45,7 @@
   <script type="text/javascript" src="spec/EnemyFactorySpec.js"></script>
   <script type="text/javascript" src="spec/AnimationSpec.js"></script>
   <script type="text/javascript" src="spec/TankExplosionFactorySpec.js"></script>
+  <script type="text/javascript" src="spec/TankExplosionSpec.js"></script>
 
   <!-- source files -->
   <script type="text/javascript" src="src/Utils.js"></script>

spec/TankExplosionFactorySpec.js

@@ -33,5 +33,6 @@ describe("TankExplosionFactory", function () {
     var explosion = factory.create(tank);
     expect(explosion instanceof TankExplosion).toBeTruthy();
     expect(explosion.getRect()).toEqual(new Rect(4, 5, EXPLOSION_SIZE, EXPLOSION_SIZE));
+    expect(explosion.getTank()).toBe(tank);
   });
 });

spec/TankExplosionSpec.js

@@ -0,0 +1,9 @@
+describe("TankExplosion", function () {
+  it("#destroyHook", function () {
+    var eventManager = new EventManager();
+    spyOn(eventManager, 'fireEvent');
+    var explosion = new TankExplosion(eventManager);
+    explosion.destroyHook();
+    expect(eventManager.fireEvent).toHaveBeenCalledWith({'name': TankExplosion.Event.DESTROYED, 'explosion': explosion});
+  });
+});

src/TankExplosion.js

@@ -1,10 +1,22 @@
-function TankExplosion(eventManager) {
+function TankExplosion(eventManager, tank) {
   Explosion.call(this, eventManager);
+  this._tank = tank;
   this._animation = new Animation([1,2,3,4,5,3], 3);
 }
 
 TankExplosion.subclass(Explosion);
 
+TankExplosion.Event = {};
+TankExplosion.Event.DESTROYED = 'TankExplosion.Event.DESTROYED';
+
 TankExplosion.prototype.getImage = function () {
   return 'tank_explosion_' + this._animation.getFrame();
 };
+
+TankExplosion.prototype.destroyHook = function () {
+  this._eventManager.fireEvent({'name': TankExplosion.Event.DESTROYED, 'explosion': this});
+};
+
+TankExplosion.prototype.getTank = function () {
+  return this._tank;
+};

src/TankExplosionFactory.js

@@ -19,7 +19,7 @@ TankExplosionFactory.prototype.notify = function (event) {
 };
 
 TankExplosionFactory.prototype.create = function (tank) {
-  var explosion = new TankExplosion(this._eventManager);
+  var explosion = new TankExplosion(this._eventManager, tank);
   var tankCenter = tank.getCenter();
   explosion.setRect(new Rect(
     tankCenter.getX() - this._explosionSize / 2,