NeatTools

Module Event Broadcast Model

Module Event Broadcast Model
(as I understand it)

Rob Salgado
30 Mar 1999

By connecting the SwitchObj-output to IntegerObj-input, we allow for the following dialogue to occur:

`SwitchObj::engine(OUTPORT) SwitchObj::broadcast(OUTPORT)`
	`IntegerObj::engine(INPORT,LINKOBJ) IntegerObj::LINKOBJ(DATA)`
`SwitchObj::access(OUTPORT,LINKOBJ,DATATYPE)`
	`IntegerObj::broadcast(OUTPORT)`

In more detail,

Suppose we depress the SwitchObj Module. This invokes its `engine()` method. [Other computations may occur in engine().] Within this method, the `broadcast()` method is called.
The `SwitchObj::broadcast(OUTPORT)` method ("pings") invokes the `engine()` method of every Module connected to the particular output port (`OUTPORT`) of the SwitchObj.
	Thus, the `IntegerObj::engine()` method is invoked. The IntegerObj Module is passed two variables: (`INPORT`) the particular input port that received the ping (`&LINKOBJ`) a link to the Module that pinged this input port In engine(), `LINKOBJ.access(DATA)` is called.
The `LINKOBJ.access(DATA)` method is a request by the IntegerObj Module via the `LINKOBJ` for data from the SwitchObj Module. This method then invokes the `SwitchObj::access(OUTPORT, &LINKOBJ, DATATYPE)` method.
Thus, the `SwitchObj::access()` method is invoked. The SwitchObj Module is passed three variables: (`OUTPORT`) that was pinged and has just replied (`& LINKOBJ`) a link to the Module that replied to this ping (`DATATYPE`) a data type of requested data Then, `SwitchObj::access()` then returns the requested data to the IntegerObj Module via the `LINKOBJ`.
	The `IntegerObj::engine()` method continues. Within this method, the `broadcast()` method is called.
The `IntegerObj::broadcast(OUTPORT)` method ("pings") invokes the `engine()` method of every Module connected to the particular output port (`OUTPORT`) of the IntegerObj. And so on... For instance, one can connect the IntegerObj-output to 1DMeterObj-input.

Based on Yuh-Jye Chang's Ph.D. dissertation (draft) and my personal experience with writing external modules.