Json layout grails respond - json

Question

Currently i'm using a custom marshaller to render json:
JSON.registerObjectMarshaller( PlannedEvent) { PlannedEvent pe ->
return [
id : pe.id,
event : [
eventId : pe.baseEvent.id,
subject : pe.baseEvent.subject
],
//rooms: pe.rooms
rooms: [
id : pe.rooms
]
]
}
This gives the following output:
{"id":1,"event":{"eventId":626,"subject":"Baggeren hc (Kv2)"},"rooms":{"id":[8]}}
I would like to know how to set up my map so the value for rooms is a list with each index representing a separate room. Instead of keys, like "id", being set up as a list. The solution in comment gives to much information about the room, so I can't use that.
Wanted result :
"rooms":[{"id":8},{"id":9}]}

Answer 1

If i am correct for your domain modelling you have a hasMany relationship between PlannedEvent & Room .So if you want to get only the list of ROOMS as IDs from the PlannedEvent domian you need to register custom marshallar for Rooms also like :
JSON.registerObjectMarshaller( Room) { Room room ->
// Map of IDs is returned from here
def returnMap = [:]
returnMap["id"] = room.id
return returnMap
}
And in PlannedEvent:
JSON.registerObjectMarshaller( PlannedEvent) { PlannedEvent pe ->
// This is also a map but the value of key rooms will contain the list of IDs of each room
def roomList = [:]
roomList["rooms"] = pe.rooms
return roomList
}
And for next time please clarify your domians & also what do you want clearly.