Set iterator doesn't work

[Warmonger]

So, the code is simple:

        for (Iterator<Monster> it = monsters.iterator(); it.hasNext(); )
        {
            Monster m = it.next();
            Vec2d v = new Vec2d(game.playerC.x, game.playerC.y);
            v.subVec(new Vec2d(m.x, m.y));
            v.unitVec();
            v.rescale(m.movement.mag());

            m.movement = v;
        }

However, does not work.

The set is declared as follows inside this class:

    Set<Character> characters = Collections.synchronizedSet(new TreeSet<Character>());

Nothing happens. However, when I use HashSet instead, it acts only for one element and ignores next ones.
I use trivial hash function for that, maybe it's the reason:

    public int compareTo(Object o)
    {
        return 0;
    }

Still, all I need is unordered collection with random access.
Your feedback would be appreciated.

[Zman3359]

Try using a while loop instead, because I'm fairly sure for loops don't work like that in Java. Here are Java's tutorials on For Loops:
The for Statement (The Java™ Tutorials > Learning the Java Language > Language Basics)
The For-Each Loop

Iterator<Monster> it = monsters.iterator();
while(it.hasNext())
{
    Monster m = it.next();
    Vec2d v = new Vec2d(game.playerC.x, game.playerC.y);
    v.subVec(new Vec2d(m.x, m.y));
    v.unitVec();
    v.rescale(m.movement.mag());

    m.movement = v;
 }

[JosAH]

I use trivial hash function for that, maybe it's the reason:

    public int compareTo(Object o)
    {
        return 0;
    }

So all objects are considered equal? While I sympathize with the idea, most certainly and a isn't a b and your set will only store one value.

kind regards,

Jos

[Warmonger]

Nope, that's not it.

I used default hashCode for Object class in comparison and it worked.

    public int compareTo(Object o)
    {
        if (hashCode() > o.hashCode())
            return 1;
        else
            return -1;
    }

[Tolls]

TreeSet uses compareTo to determine whether something is equal, so mucking up compareTo such that it does not give the same results as equals() for example...well, you get what you deserve. It's all there in the docs after all.

As for HashSet, have you mucked up the hashcode method as well?

[JosAH]

Nope, that's not it.

I used default hashCode for Object class in comparison and it worked.

    public int compareTo(Object o)
    {
        if (hashCode() > o.hashCode())
            return 1;
        else
            return -1;
    }

Yes, your previous implementation of the compareTo( ... ) method was faulty and your current implementation doesn't make sense if you haven't overridden the hashCode() method and even then it is faulty. Read the API documentation for the Comparable<T> interface.

kind regards,

Jos