source: galactic-heroes/Level.java

import java.util.Collection;
import java.awt.Graphics;
import java.util.ArrayList;

public class Level extends ArrayList {
    public void draw(final Graphics g) {
        for (int x = 0; x < this.size(); ++x) {
            if (((Ship)this.get(x)).getHitpoints() <= 0 && ((Ship)this.get(x)).getShots().size() == 0) {
                this.remove(this.get(x));
            } else {
                ((Ship)this.get(x)).draw(g);
            }
        }
    }
    
    public void copy(final Level permLevel) {
        this.clear();
        this.addAll(permLevel);
    }
    
    public void reset() {
        for (int x = 0; x < this.size(); ++x) {
            ((Ship)this.get(x)).reset();
        }
    }
}