Get all Objects in an applet

[Nark]

Hi there,

is there a way I can get the names of all objects my applet is using and store them in an array?

When that is done I want to filter them so that I'm only left with some objects with special methods and atributs.  

I want to program a physics engine and thing this is a way of letting my physics class handle all my objects that should be handled in one go. It can then check all these objects o collisions, gravity, speed, friction and so on.

Is my attempt possible?

[NewbTon]

Don't understand your question.

[Nark]

My problem is that my program has to handle an unknown amount of objects that are supposed to interact with each other. So first I need to find out how many objects my program uses. Then I need to find out which of these objects realy are objects that are supposed to interact with each other (so to speak my "world-objects") and which are used for other stuff such as keyboard handling. The "world-objects" have all inherited surtain methods and attributes from a basic class, so these methods and attribues are in common to all of these objects.

So now I need to find a way of parsing these objects one by one through my physics engine.

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[NewbTon]

My problem is that my program has to handle an unknown amount of objects that are supposed to interact with each other. So first I need to find out how many objects my program uses. Then I need to find out which of these objects realy are objects that are supposed to interact with each other (so to speak my "world-objects") and which are used for other stuff such as keyboard handling. The "world-objects" have all inherited surtain methods and attributes from a basic class, so these methods and attribues are in common to all of these objects.

So now I need to find a way of parsing these objects one by one through my physics engine.

Theres no way you can retrieve all the objects that your applet is using. Those objects could be anything from buttons to strings to your own classes. If you have an
arrays of OBjects, for instance, you can do something like this :
Object [] objects;
for(int i=0;i<objects.length;i++) {
  if(objects instanceof MyClass) {
       // do something
 }

}
You use the instanceof operator to determine the class of the object.  You question sounds a litte strange to me, since in what situation would you NOT know what kind of objects your application/applet uses ?  
OK lets say you do find out that some applet uses 100 Strings, 20 buttons and 25 Int arrays. What would you use that for, how could you possible fit that into a physics engine ? I'm sure you know what your doing, but I think you must be more specific so other people can understand your problem.

[Danskeren]

I would recoomend you to use som sort of List (Like ArrayList) instead of an array. This way you wont have to worry about resizing the array.

Lets say you have different lists for different things and one of your things is just called Thing. Then I would do this:

1   2   3   4   5   6   7   8   9   10   11

Arraylist<Thing> things = new ArrayList<Thing> Arraylist<OtherThing> otherThings = new ArrayList<OtherThing> things.add(new Thing()); things.add(new Thing()); things.add(new Thing()); otherThings.add(new OtherThing()); otherThings.add(new OtherThing()); otherThings.add(new OtherThing()); otherThings.add(new OtherThing()); otherThings.add(new OtherThing());

and when you update your things (Like check collisions or just painting to the screen you just run through the Lists with loops)