I have a project that involves one array of thousands of circular objects.  To apply some change to all of them, I use the usual for() loop to cycle through each one, and call a method, etc.

But now I want the ability to apply a change to only a *subset* of the objects, and I want to be able to order them.  For example, I want to identify only the objects at a certain z depth value, and then sort them by largest to smallest.  The end goal is to then feed this list of objects, in sorted order, to a method that will do something with them (e.g. cluster or arrange them by size, left to right).

I thought this would be possible by creating a second array of objects, and then "copying" or "referencing" the subset of objects in that new array.  For example, here is a portion of my code:

Code:

  //Create a new object array to store all objects to be clustered
  Object[] objectsToCluster = new Object[1];
  objectsToCluster[0] = new Object(0, 0);

  //Grab all objects with a z depth of zero and throw them in the array
  for (int i = 0; i < objects.length; i++) {
    if (objects[i].z == 0) {
	objectsToCluster = (Object[]) append(objectsToCluster, objects[i]); 
    }
  }
 

The intent is for the for() loop to cycle through all objects, find the ones where z == 0, and then append them to the objectsToCluster array.

So I guess I have a few questions -- responses to any would be helpful.

1)  Does this approach make sense?

2)  Once I have copied the subset of objects over into the new array, how can I sort them by size?  (Are ArrayLists or HashMaps the answer?  I don't understand either.)

3)  I get an error when trying to pass this new array of objects to a method.  What does "object1.radius cannot be resolved or is not a field" mean?

Thanks, PhiLho! I will give this a shot this afternoon.

And sorry for the confusion — in the real sketch, my object class is not called "Object."  I rewrote it here in an attempt to minimize confusion.