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Note
You can learn more about creating and using ActiveX/COM/DCOM components in Visual Basic 5 Development Unleashed by Sams Publishing. |
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Revisiting the Unified Modeling Language (UML) |
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Since fall 1994, Grady Booch and James Rumbaugh, and later Ivar Jacobson, have led a group of professionals on a quest to unify the ways that object-oriented designers and programmers express the details of their proposed applications. Their quest was supported by the Object Management Group, which pursued a common modeling language. While developing this modeling language, the Three Amigos (as they're affectionately known) used this common notation development as a good excuse to also unify some methodology concepts. This section covers the simpler notions of the modeling language notation. |
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The Unified Modeling Language (UML) provides a common set of notational symbols to describe the architecture of a system, including use cases. Although some concepts embodied in the notation are a subject of interesting debate in the object technology community, UML 1.1 is gaining wide acceptance. A related notation, the Object Modeling Language, is also starting to gain some credible momentum; it is more an appendage to UML. |
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The UML supports the following important features: |
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Object interaction modeling using sequence and collaboration diagrams |
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Object and use-case state transition modeling |
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Application partitioning using packages |
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Class and component file organization |
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Sequence and collaboration diagrams express the communication of stimuli (or messages) between objects. Sequence diagrams show sequential steps of events, whereas collaboration diagrams express a fuller relationship between objects. Because objects and even use cases can change state, state diagrams help to explicitly describe these states. Packages enable you to divide an application into groups of logically related classes, thus helping to reduce complexity and allow for better allocation of development tasks. The component diagram provides you with a visual snapshot of the underlying file structure of classes and components. |
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The UML supports many icons. For more detailed information on UML icons, please visit the Rational Web site at www.rational.com, or browse Microsoft Visual Modeler. Figure 5.2 shows the icons discussed in this section. |
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