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2.2.2 Declarative Specification

The Object Constraint Language (OCL), as a declarative specification language, is already included in the UML standard. It is very useful in specifying guards in statecharts, pre- and post-conditions of methods, and all kinds of boolean expressions in UML.

However, though the pre- and post-conditions define the input sets and output sets of a method, OCL has no ability to specify algorithms, i.e., which input value matches to which output value [MTAL98]. This task must be taken up by another more powerful and more expressive language.



Thomas Feng 2003-04-18