Bukkit

CharsUpdater - that is class who manage your chars, and changing it.

CharsUpdater updater = new CharsUpdater(int, org.bukkit.Location, org.bukkit.block.BlockFace);

1. Seconds with updater change chars
   
2. Location where he change chars
   
3. Face - rotation with where he will building chars

Adding chars to updater:

int ID = updater.addCharsString(builder, String format);

Chars will be builded with settings (font, spacing and etc.), like have your builder when you add chars.
This function return Integer - ID of added chars.

Removing chars:

updater.removeCharsString(ID);

Changing seconds of updating:

updater.setSeconds(int);

Changing location of updating:

updater.setLocation(Location);

Changing face chars:

updater.setFacing(BlockFace);

Checking about updater is working:

updater.isRunning();

And finaly:

Staring updater:

updater.start();

Stoping updater:

updater.cancel();

I prefere everytime when you adding / changing something in updater stopping him, and after changes starting.