Description. Party A makes a request to party B which
delegates the request to other parties (P1, ..., Pn). Parties P1, ...,
Pn then continue interactions with party A while party B observes a
"view" of the interactions including faults. The interacting parties
are aware of this "view" (as part of the condition to interact).
Case 1: Without
fault
A customer sends a request to an
agency which relays the request to two contractors. The contractors
then interact with the customer (messages denoted by blue circles)
while keeping the agency informed of these interactions (messages
denoted by green circles).
In the terminology of the pattern description, party A = customer,
party B = agency, P1 =Contractor 1 and P2 = contractor 2.
Case 2: With fault
Same scenario as above but the
interaction with one of the contractors results in a fault. Both the
agency and the customer receive an error message from this contractor
(denoted by a red
circle).