Software Architecture Diagram (SAD)

The software architecture design activity integrates the results of the process and class structuring activities. This integration combines both the dynamic and static views of the software system by identifying the interactions between processes and objects in a language-independent fashion. To identify an interaction between a process and an object, examine the process and class behaviour specifications. The process logic documents when a process is activated (i.e. via an event or message) and what the process does. To service the event or message, a process often needs to operate an object by invoking operations that define how the process logic is carried out. During this activity, you create and document the process interactions with objects and their operations. These interactions are recorded in a SAD.

The SAD shows the processes (with communications and synchronisation), objects (with dependencies), and the interactions among processes and objects.

SADs are not hierarchical.

SADs only appear in the Implementation Domain.

Numbering of SADs

The numbering system for SADs is alphanumeric.

Symbols

An example SAD is:

The symbols available in SADs are:

Symbol	Name	Description	Definition	Expansion
	Comment	Makes a note anywhere in the diagram. Are always surrounded by * characters.	None	None
	Boundary Point	A connection point for the initial transition to enter the initial state.	None	None
	Environment	Represents external system or environment to this system.	Environment	None
	Off-Page Connector	Means to connect any event or message or data link in two parts either on the same SAD or between SADs, where a linkage between SADs is effected by having off-page connectors on each SAD with the same name and where one is an input (has connectors entering it) and the other is an output (has connectors leaving it) and if both it is an input.	None	None
	Picture	Allows you to choose the location of a GIF or JPEG image to be displayed as a diagram symbol or to be embedded in an existing diagram symbol.	None	None
	Process or Task	Process or task element which can contain entries.	Task specification	None
	Class or Object	Packaging element, typically within a task (but sometimes the other way round), can contain routines.	Class specification	None
	Process/Task Entry	An entry in a process or task symbol. This can only exist within a process or task symbol.	None	None
	Class/Object Routine	A routine (procedure or function) in a class or object symbol. This can only exist within a class or object symbol.	None	None
	Data Store	Allows static data buffers to be depicted. It is only significant in the consistency checks of individual SADs in the tests of the inputs to, and outputs from, such stores.	Data definition	None
	FIFO Message Queue	A first-in-first-out buffer of messages between elements.	None	None
	Prioritised FIFO Queue	A prioritised first-in-first-out buffer of messages between elements.	None	None
	Event	The indication of an event.	Data definition	None
	Message	A data message between elements.	Data definition	None
	Message with Reply	A data message between elements which has an acknowledgement.	Data definition	None
	Data Link	A general purpose data connection between elements.	Data definition	None