// January 19, 2014
//----------------------------------------------------------------------------------------
// 	Two components communicating via unreliable channel
// 	from 
// 	Mikhail Auguston, Example 10 in Monterey Phoenix System and Software Architecture
// 	 Modeling Language (Draft): Examples of architecture models  
// 	 Naval Postgraduate School, Monterey, CA, USA
// 	http://faculty.nps.edu/maugusto/
// 	for Eagle6: runs up to the scope 4, before running out of memory.
//---------------------------------------------------------------------------------------- 

//SCHEMA AtoB

ROOT TaskA: (* A_sends_request_to_B
                 ( A_receives_data_from_B |
                   A_timeout_waiting_from_B_1 |
		   A_timeout_waiting_from_B_2 )
            *);

//assumes that A is the leading actor;
//this model can be modified making A and B to behave similarly 

ROOT TaskB: (* (B_working | request_bounces_back) *);

 B_working: B_receives_request_from_A B_sends_data_to_A;

// request_bounces_back activity simulates the connector's
// unsuccessful attempt to connect to B

ROOT Connector_A_to_B: (* A_sends_request_to_B
                         ( B_receives_request_from_A |
                           ( [ request_bounces_back ]  A_timeout_waiting_from_B_1) )
                       *);

// A_timeout_waiting_from_B may happen either because
// Connector_A_to_B just fails or because TaskB is not working 

ROOT Connector_B_to_A: (* B_sends_data_to_A
                           ( A_receives_data_from_B |
                             A_timeout_waiting_from_B_2 ) *);

// sharing constraints
TaskA, Connector_A_to_B SHARE ALL A_sends_request_to_B;

TaskB, Connector_A_to_B SHARE ALL B_receives_request_from_A,
                                 request_bounces_back;

TaskB, Connector_B_to_A SHARE ALL B_sends_data_to_A;

TaskA, Connector_B_to_A SHARE ALL A_receives_data_from_B;

// TaskA, Connector_A_to_B |+| Connector_B_to_A SHARE ALL
//                                A_timeout_waiting_from_B;
// |+| means an exclusive union (i.e. a partitioning of shared 
// events), A_timeout_waiting_from_B can not be shared by both
// Connector_A_to_B and Connector_B_to_A. -- not implemented in Eagle6

// approximation to get around Eagle6 constraints
TaskA, Connector_A_to_B  	SHARE ALL 	A_timeout_waiting_from_B_1;
TaskA, Connector_B_to_A 	SHARE ALL	A_timeout_waiting_from_B_2;