grounds

An extensible MUSH / MUD server written in Java.

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Events

Commands are what makes things happen in a Grounds universe, and many commands generate events describing what happens. Events on their own are invisible to players, but listener attributes on extensions can react to events by running plugins, which may in turn run more commands. This helps to make a universe feel more alive, beyond the players in it.

Event Types

Every event has a type which describes what happened to trigger it. These are usually tied to the command that caused the event to be posted in the first place, but some events are not tied to a command.

Type	Command	Cause
ArrivalEvent	n/a	A player arrived (logged in)
DepartureEvent	n/a	A player departed (logged out)
DroppedThingEvent	DROP	A thing was dropped by a player
SayMessageEvent	SAY	A message was said
TakenThingEvent	TAKE	A thing was taken by a player
TeleportArrivalEvent	TELEPORT	A thing arrived at a location
TeleportDepartureEvent	TELEPORT	A thing departed from a location
YoinkArrivalEvent	YOINK	A yoinked thing arrived at a location
YoinkDepartureEvent	YOINK	A yoinked thing departed from a location

Note: In Grounds, the MOVE command causes a TELEPORT, so ordinary player movement also triggers Teleport* events.

Event Payload

Every event has a JSON object called a payload with context about the event, beyond the type. Each event type may have its own payload structure. The following fields are standard, but they are not necessarily present in every event.

Field name	Definition
location	name of location where event occurred
locationId	ID of location where event occurred
player	name of player who caused event
playerId	ID of player who caused event

Here are the payload fields provided by the different event types.

Type	Player	Location	Other
ArrivalEvent	arriving player	n/a	n/a
DepartureEvent	departing player	n/a	n/a
DroppedThingEvent	dropping player	dropping location	thingId = ID of dropped thing thingName = name of dropped thing
SayMessageEvent	saying player	saying location	message = said message
TakenThingEvent	taking player	taking location	thingId = ID of taken thing thingName = name of taken thing
TeleportArrivalEvent	arriving player	location of arrival	none
TeleportDepartureEvent	departing player	location of departure	none
YoinkArrivalEvent	not present	location of arrival	yoinkedThingId = ID of arriving thing yoinkedThingName = name of arriving thing yoinkedThingType = type (as simple class name) of arriving thing
YoinkDepartureEvent	not present	location of departure	yoinkedThingId = ID of departing thing yoinkedThingName = name of departing thing yoinkedThingType = type (as simple class name) of departing thing