primes iterator and iterable

PrimesTest.java

import java.util.*;

/*
you can use it like this
  PrimesIterator primes=new PrimesIterator(10000);
  while(primes.hasNext()){
    System.out.println(primes.next());
  }
*/
class PrimesIterator implements Iterator<Integer> {
    protected boolean is_done=false, pending_value=false;
    protected int i=2,j,n, value=0;
    HashSet<Integer> compo;
    PrimesIterator(int bound) {
      n=bound;
      compo=new HashSet(n);
    }
    
    public void clear() {
        i=2;
        is_done=false;
        pending_value=false;
        compo.clear();
    }
    
    protected void do_iteration() {
        if (i>=n) {is_done=true; return;}
        if (!compo.contains(i)) {
          pending_value=true;
          value=i;
          for(j=i*2;j<n;j+=i) compo.add(j);
        }
        ++i;
    }
    
    public boolean hasNext() {
        while(!is_done && !pending_value) do_iteration();
        return !is_done;
    }

    public Integer next() {
        while(!is_done && !pending_value) do_iteration();
        if (pending_value) {
           pending_value=false;
           return value;
        } else throw new NoSuchElementException("Out of bound, you should call hasNext");
    }
    
    public void remove() {
        if (value>0) pending_value=true;
        else throw new IllegalStateException();
    }

}

/*
you can use it like this
  for(int p : new PrimesIterable(10000)){ System.out.println(p); }
*/
class PrimesIterable implements Iterable<Integer> {
    protected int n;
    PrimesIterable(int bound) { n=bound; }
    public Iterator<Integer> iterator() {
        return new PrimesIterator(n);
    }
    List<Integer> toArrayList() {
        List<Integer> list = new ArrayList<Integer>(n);
        Iterator<Integer> iter=new PrimesIterator(n);
        while (iter.hasNext()) list.add(iter.next());
        return list;
    }
}

class PrimesTest {
    public static void main(String[] args) {
        int c;
        long t0=System.currentTimeMillis();
        for(c=0;c<500;++c) {
           List<Integer> a=new PrimesIterable(10000).toArrayList();
           //for(int p : new PrimesIterable(10000)){ }
        }
        System.out.println(System.currentTimeMillis()-t0);
    }
}