hello list! im trying  to create an array of objects . i want to create a new object each 6 seconds and add it to my array, looking for information about doing this i discovered that java has 2 mutable structures for storing object: arraylist and vector,
so i decide to use vector.
the idea is really simple. my class creates an animated dot.
so i would like that each 6 seconds a new animated dot (object) appears on my screen and add it(object) to the array.

heres the code, can anybody explain me why it doesnt work?



Vector a= new Vector();

int lastRun;

void setup()
{
 size(200, 200);
 stroke(255);
 framerate(30);
  lastRun=0;
  a.add(new punto(200,200));


}
void draw()
{
background(51);

a.display();



int m=millis();
 if(m>=(lastRun+6000))
 {
    lastRun=m;
    a.add(new punto(200,200));
 
}


}
class punto
 {
   int x;
   int y;
punto( int xa, int ya){

   float xf=random(xa);
float yf=random(ya);
 x= int(xf);
 y= int(yf);
print(x);

   }
 
 void display(){
    x = x - 1;
 if (x < 0) {
   x = height;
 }
   point(x,y);
   }  

}

One of the problems with Vector is that it neither knows nor cares what kind of Object you put in it, so to do anything with an object stored in a vector, you have to cast it to a certain type before you can do anything with it.

For example, if you do
Code:

a.add(new punto(200,200)); 

the Vector doesn't know that it's got a "punto" just an object, so to use the contained punto you'll have to do something like:
Code:

a.add(new punto(200,200));
...
for(int i=0;i<a.size();i++)
{
  punto tmp=(punto)a.get(i);
  tmp.display();
} 

I think this is the syntax in Java.

Unfortunately, or possibly fortunately, it doesn't work like in C++ where a Vector is created to handle a number of a single type of object. You can put in any number of different types of object, and the Vector won't care. You'll have to do some voodoo to find out what type the one you've just retrieved is though.