AS3 - Accessing subclass of subclass - actionscript-3

Question

Im making this game, and I really want to access a "subclass of subclass". So I have something like this: MainClass > MonsterLibrary > SampleMonster.
I want to add this Sample Monster from MainClass, but I have to use it through MonsterLibrary, so I dont have to add monster by monster at my MainClass. Every monster respawn would be written in MonsterLibrary class.
I guess it should be something like this.
public class MainGame extends MovieClip {
public function MainGame() {
var mylibrary:MonsterLibrary = new MonsterLibrary();
mylibrary.MonsterLibrary();
Main class.
public class MonsterLibrary extends MovieClip {
#all var here.#
public function MonsterLibrary(){
var monster:SampleMonster = new SampleMonster(330,250);
addChild(monster);
}
MonsterLibrary class.
public class SampleMonster extends MonsterLibrary{
public function SampleMonster(startX:Number, startY:Number) {
//SETTING STARTING LOCATION
x = startX;
y = startY;
SampleMonster class.
I know Im doing it wrong, but I have no idea how to make this work. I keep getting this error ->
1061: Call to a possibly undefined method MonsterLibrary through a reference with static type MonsterLibrary.

Answer 1

You get that error because you're trying to directly call the constructor of MonsterLibrary:
public function MainGame()
{
var mylibrary:MonsterLibrary = new MonsterLibrary();
mylibrary.MonsterLibrary(); // <- wrong
...
}
The MonsterLibrary() function is the constructor of the MonsterLibrary class and it's called automatically when you use the new operator to create a new instance of the class.
If you want your MonsterLibrary class to act as a monster factory (a class that creates monster objects), create a new function that returns a monster:
...
public function CreateMonster ( sType:String ):SampleMonster
{
var oMonster:MovieClip = null; // you can use BaseMonster instead of MovieClip
if ( sType == "SampleMonster" )
{
oMonster = new SampleMonster ( ... );
... // initialize the monster here
}
...
return ( oMonster );
}
...
// get a monster and add it to the stage
var oMonster:MovieClip = oMonsterLibrary.CreateMonster ( "SampleMonster" );
oStage.addChild ( oMonster );
Note that MonsterLibrary doesn't need to extend MovieClip - it really doesn't need to extend any type (other than Object) since (I assume) it's not a visual object. Its purpose is to be a factory, not to be on the screen. oStage in the code above is your top-level display object - it could be the actual stage or a DisplayObject that acts as your stage.
The SampleMonster type shouldn't extend MonsterLibrary - a particular monster is not a library. Your monsters should derive either directly from MovieClip or (better) from a common base monster class; something like:
public class BaseMonster extends MovieClip
{
...
}
Then your SampleMonster can derive from this base monster:
public class SampleMonster extends BaseMonster
{
...
}

Answer 2

I'm confused at what you are trying to accomplish.
Are you looking to have the MonsterLibrary return a monster every time you call a method ?
ie you could have a method in MonsterLibrary class like this :
public function getMonster():SampleMonster
{
var monster:SampleMonster = new SampleMonster(330,250);
return monster;
}
Then your MainGame might look like this :
public class MainGame extends MovieClip {
public function MainGame() {
var mylibrary:MonsterLibrary = new MonsterLibrary();
var newMonster:SampleMonster = mylibrary.getMonster();
addChild(newMonster);
Going further you could have a parameter for the getMonster method to specify a monster type.
for example :
public function getMonster(monsterType:int):Monster
{
// create the appropriate monster and return it
}
Keep in mind that in your code adding the monster to the Display List of the MonsterLibrary, means it will never be seen UNLESS you add MonsterLibrary to the Display List of MainGame
Also you have SampleMonster extending MonsterLibrary, which is not going to work.
SampleMonster should probably extend MovieClip or Sprite or if you intend on having multiple monsters you'd want to have a base Monster Class that any specific monster might extend.