James Rumbaugh Quotes

If two classes express the same information, the most descriptive name should be kept. For example, although customer might describe a person taking an airline flight, Passenger is more descriptive.

I know that I disagree with many other UML experts, but there is no magic about UML. If you can generate code from a model, then it is programming language. And UML is not a well-designed programming language. The most important reason is that it lacks a well-defined point of view, partly by intent and partly because of the tyranny of the OMG standardization process that tries to provide everything to everybody. It doesn't have a well-defined underlying set of assumptions about memory, storage, concurrency, or almost anything else. How can you program in such a language? The fact is that UML and other modelling language are not meant to be executable. The point of models is that they are imprecise and ambiguous. This drove many theoreticians crazy so they tried to make UML "precise", but models are imprecise for a reason: we leave out things that have a small effect so we can concentrate on the things that have big or global effects. That's how it works in physics models: you model the big effect (such as the gravitation from the sun) and then you treat the smaller effects as perturbation to the basic model (such as the effects of the planets on each other). If you tried to solve the entire set of equations directly in full detail, you couldn't do anything.

Constructs extraneous to the real world should be eliminated from the analysis model. They may be needed later during design, but not now. For example, CPU subroutine, process, algorithm, and interrupt are implementation constructs for most applications [and should be excluded from the analysis model]...

The (UML) is a general-purpose visual that is used to specify, visualize, construct, and document the artifacts of a software system. It captures decisions and understanding about systems that must be constructed. It is used to understand, design, browse, configure, maintain, and control information about such systems. It is intended for use with all development methods, lifecycle stages, application domains, and media. The modeling language is intended to unify past experience about modeling techniques and to incorporate current software best practices into a standard approach. UML includes semantic concepts, notation, and guidelines. It has static, dynamic, environmental, and organizational parts. It is intended to be supported by interactive visual modeling tools that have code generators and report writers. The UML specification does not define a standard process but is intended to be useful with an iterative development process. It is intended to support most existing object-oriented development processes.

The name of a class should reflect its intrinsic nature and not a role that it plays in an association. For example, Owner would be a poor name for a class in a car manufacturer's database. What if a list of drivers is added later? What about persons who lease cars? The proper class is Person (or possibly Customer), which assumes various different roles, such as owner, driver, and lessee.