[Graham]

Hi everyone. I've been planning out a concept for dealing with the vast majority of actions that will take place in the MUD server I'm writing and I'm interested in any feedback/suggestions people have, or if anybody has done something similar before in a MUD server.

Essentially, every object in the game can create events. When an event is published, it is sent to the subscribers of the object. The subscribers can then react accordingly.

For example, when a player object receives an event from one of its subscriptions, it will format it into a text message and send it to the client at the other end of the socket. Almost everything that happens in game will be an event, here is a little example from my 'proof of concept' implementation.

The following code snippet is the actual event class itself. Every event is derived from Event<T> where T is the type of subject (the subject is the object that creates the event). The use of generics is just to reduce casting everywhere.

As you can see there are two ways to get data out of the event: toMessage() which formats it for players. As well as that, events will also have get...() methods which could be used for NPCs or other objects which are capable of reacting to events.

This is the command which actually publishes chat commands. It's quite simple: it just creates a single string from the command parameters, creates a ChatEvent with the player that issued the command as the subject and publishes it.

The subscribers of a player object are the other objects in the room. So, if there is another player in the room, this method is called when the event is published:

Which will ultimately send the formatted message to the player (if they are online).

The possibilities are almost endless. You could create fairly complex behaviours for special objects/NPCs and not have to write code elsewhere.

For example, imagine that the players are sneaking around in a dark tunnel and nobody can see much (include some NPCs). If a hostile NPC which had poor vision received a ChatEvent, it could then sense that somebody is there and attack them. The corresponding AttackEvent would be received by other NPCs e.g. mice which might run away to other, adjancent rooms, scared due to the violence that is going on. All of this could be done without ever adding anything to the chatting code or attacking code itself.

Back onto the more technical aspect, has anyone got any feedback/ideas or can see any glaring problems with the concept?