private void writeObject(ObjectOutputStream stream) throws IOException {
        stream.defaultWriteObject();
        stream.writeInt(this.store.size());
        Set keys = this.store.keySet();
        Iterator iterator = keys.iterator();
        while (iterator.hasNext()) {
            Comparable key = (Comparable) iterator.next();
            stream.writeObject(key);
            Paint paint = getPaint(key);
            SerialUtilities.writePaint(paint, stream);