I'm making a simple game, and have decided to try to implement a messaging system.
The system basically looks like this:
Entity generates message - message is posted to global message queue - messageManager notifies every object of the new message through onMessageReceived(Message msg) - if object wants, it acts on the message.
The way I'm making message objects is like this:
//base message class, never actually instantiated
abstract class Message{
Entity sender;
}
PlayerDiedMessage extends Message{
int livesLeft;
}
Now my SoundManagerEntity can do something like this in its onMessageReceived() method
public void messageReceived(Message msg){
if(msg instanceof PlayerDiedMessage){
PlayerDiedMessage diedMessage = (PlayerDiedMessage) msg;
if(diedMessage.livesLeft == 0)
playSound(SOUND_DEATH);
}
}
The pros to this approach:
Very simple and easy to implement
The message can contain as much as information as you want, because you can just create a new Message subclass that has whatever info necessary.
The cons:
I can't figure out how I can recycle Message objects to a object pool, unless I have a different pool for each subclass of Message. So I have lots and lots of object creation/memory allocation over time.
Can't send a message to a specific recipient, but I haven't needed that yet in my game so I don't mind it too much.
What am I missing here? There must be a better implementation or some idea that I'm missing.
