notifyListeners: Notifies listeners that a new message is available.

In ralmond/Proc4: Four Process Assessment Database and Dispatcher

Notifies listeners that a new message is available.

Description

This is a generic function for objects that send P4Message objects. When this function is called, the message is sent to the listeners; that is, the receiveMessage function is called on the listener objects. Often, this protocol is implemented by having the sender include a ListenerSet object.

Usage

notifyListeners(sender, message)

Arguments

sender	An object which sends messages.
message	A P4Message to be sent.

Value

Function is invoked for its side effect, so return value may be anything.

Author(s)

Russell Almond

See Also

P4Message, Listener, ListenerSet

Examples

## Not run: ## Requires Mongo database set up.
MyListener <- setClass("MyListener",slots=c("name"="character"))
setMethod("receiveMessage","MyListener",
   function(x,mess)
      cat("I (",x@name,") just got the message ",mess(mess),"\n"))


lset <-
ListenerSet$new(sender="Other",dburi="mongodb://localhost",
                colname="messages")
lset$addListener("me",MyListener())

mess1 <- P4Message("Fred","Task 1","Evidence ID","Scored Response",
         as.POSIXct("2018-11-04 21:15:25 EST"),
         list(correct=TRUE,seletion="D"))

mess2 <- P4Message("Fred","Task 2","Evidence ID","Scored Response",
         as.POSIXct("2018-11-04 21:17:25 EST"),
         list(correct=FALSE,seletion="D"))

lset$notifyListeners(mess1)

lset$removeListener("me")

notifyListeners(lset,mess2)


## End(Not run)

ralmond/Proc4 documentation built on June 13, 2025, 7:13 a.m.