Deciding Which Software Solution to Use

When you use Microsoft Office Visio Professional 2007 to document a software system, the template and shapes you use depend on the task you want to perform, the type of diagram you want to create, and the notation you want to use. Office Visio Professional 2007 includes two general types of software templates: static software diagrams and dynamic models. For creating static software diagrams, Visio Professional 2007 provides six templates with a simple drag-and-drop approach to software modeling. Some shapes conform to the notation used by a particular modeling methodology, but Visio Professional 2007 doesn’t check for compliance or semantic correctness. You can use the following templates to document software systems using static software diagrams:

• COM And OLE Use this template to create diagrams of Component Object Model (COM) and OLE interfaces for object-oriented programming and diagrams of public, exposed interfaces. Drag shapes such as COM Objects, Vtables, Process Boundaries, and Data Stores onto the drawing page, and connect them with Interface and Reference shapes to create a diagram.

• Enterprise Application Use this template to illustrate the requirements of large-scale business application architecture. Create logical models that identify business objects, services, and interfaces and physical models that show the physical architecture for your application. Drag shapes that represent PCs, mainframes, laptops, and architecture layers, and connect architecture shapes with Interface or Communication Link shapes.

• Jackson Use this template to create diagrams that conform to the methodology developed by Michael Jackson for structured design and structured programming. With the Jackson method, you systematically map the structure of a problem to a program structure using diagrams that reveal data sequences, repetition, hierarchy, and alternatives. Drag Procedure and Process shapes onto the drawing page, and connect them with Tree Connector and Logical Connector shapes to create your diagram.

• Program Structure Use this template to document program architecture, including data flows, function calls, and memory management. Create structural diagrams, memory diagrams, and flowcharts using shapes that represent memory objects (stacks, arrays, pointers, and data blocks) and language constructs (functions, subroutines, and calls).

• ROOM Use this template to create diagrams that conform to the Real-Time Object-Oriented Modeling (ROOM) method, which tailors object-oriented concepts to real-time systems. Create structure diagrams that represent system components and their relationships as well as behavior diagrams (ROOMcharts) that model a system’s response to events.

• Windows XP User Interface Use this template for creating prototypes of Microsoft Windows XP user interfaces. Use shapes to represent wizards, tabbed dialog boxes, toolbars, dialog boxes, and other user interface components.

In addition, Visio Professional 2007 includes two templates that are complete dynamic software modeling environments, the Data Flow Model Diagram and UML Model Diagram templates.

Note that the Data Flow Model Diagram Model Explorer has been removed from the Data Flow Model Diagram template, but still resides in the UML Model Diagram template. The following section introduces the Data Flow Model Diagram template and the remainder of the chapter details the UML Model Diagram template.

Inside Out: Using Enterprise Application and Windows XP User Interface templates The Enterprise Application and Windows XP User Interface templates are designed to work together to provide a complete picture of your system architecture and user interface. When you start a diagram with one template, you can add shapes from the other. To open a stencil, click the the Shapes button on the Standard toolbar, open the Software And Database folder, then the Software folder, and then select the stencil you want.

Using the Data Flow Model Diagram Template

Whether you’re familiar with the formal Gane-Sarson notation or not, the Data Flow Model Diagram template in Visio Professional 2007 provides a model-based, top-down approach to data flow diagrams (DFDs). With a DFD, you don’t model processes, you discover the data in the processes by depicting information flow and the transformations that are applied as data moves from input to output. Chris Gane and Trish Sarson wrote one of the classic books on structured analysis and design (Structured Systems Analysis: Tools and Techniques, IST, Inc., New York: 1977), and their DFD notation is represented in the shapes of the Gane-Sarson stencil.

To open the Data Flow Model Diagram solution, choose File, New, Software And Database, Data Flow Model Diagram. Visio Professional 2007 opens the Gane-Sarson stencil and a drawing page, as Figure 20-1 shows.

Drag Process, Interface, Data Store, and Data Flow shapes onto the drawing page to build your model.

For details about data flow diagrams, refer to Visio Help. Choose Help, Microsoft Office Visio Help. Click Software And Database Model Diagrams, then click Other Software Modeling Diagrams. (Make sure your Help system is connected to Office Online.)