Datasheet

Chapter 1 ✦ What Is UML?

working with UML for a while, these items should demonstrate the OMG’s commit-

ment to the long-term success of UML.

Improve the architecture: Rework the physical metamodel so that it is more tightly

aligned with the MOF meta-metamodel. Improve the guidelines that establish what

constructs should be defined in the kernel language and what constructs should be

defined in UML profiles or standard model libraries. (See Chapter 2.)

Provide improved extensibility: Enhance the extensibility mechanisms to align

them more closely to a true “four-layer architecture.” Profiles provide much of the

customization support, at least in concept. But the extensibility features used to

create them (stereotypes, tagged values, and constraints) are still rather low-level.

UML extensibility features should align more closely with the MOF extensibility fea-

tures, that is, metaclasses. (See Chapters 2 and 3.)

Improve support for component-based development: Current technologies such

as EJB and COM+ require a means to model and manage component-based designs.

The current semantics and notation are not quite up to the task. (See Chapters 15

through 17.)

Improve the modeling of relationships: Improve the semantics for «

refinement»

and «

trace» dependencies. Today it is difficult to support refinement of the models

through the life cycle of a project, that is, analysis to design or design to implemen-

tation. (See Chapter 6.)

Separate the semantics of statecharts and activity graphs: The initial UML specifi-

cation tried to define activity graphs as a specialization of a statechart. The overlap

has created obstacles to business modeling and has prevented the addition of valu-

able business modeling features. Support more relaxed concurrency in both dia-

grams. Support specialization of state machines. (See Chapters 11 and 13.)

Improve model management: Update the notation and semantics for models and

subsystems to improve support for enterprise architecture views.

General mechanisms: Define support for model versioning.

The Object Management Group

The organization responsible for developing the UML goals described previously is

the Object Management Group (OMG). The OMG is the official steward of the UML

standard. This is not simply because the OMG likes standards or likes to take on

work, but because it is the driving force behind a much larger plan for software

development called Model-Driven Architecture (MDA). MDA is a genuinely ambi-

tious effort to standardize systems development. The goal is to create a complete

standard for the creation of implementation-independent models that may be

mapped to any platform, present or future. Did I say it was ambitious?

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