[Uml-devel] Whats next for associations? UML?

[Brian Thomas]

	Hi again.

	Im trying to hammer out my final code for the javacodegenerator fix up and I now see	
	that it would be desirable to have multiplicty (that is to say UML "notation") more strictly
	controled by the program. Currently, notation is represented as a string, and you can put
	anything you please there, which may or may not be valid notation.

	At the very least, there should be some validation of the multiplicity string when it is input.
	Even better, a small class should be created to control and hold this information, and this
	small class should make it relatively easy for codegenerator writers to parse the meaning
	of the notation. To quantify the needed functionality, here is a brief summary. The 1.4 UML 
	spec for notation is:

	lower-bound .. upper-bound

	where "lower-bound" and "upper-bound" must be non-negative integers. The range modifier
	is the ".." which means all integers between the bounds exist. The upper-bound is not required,
	and IF it isnt specified then the range indicator isnt used. The upper-bound must always be greater
	than the lower-bound (if it is specified). There is one special symbol, the star '*' which has meaning
	based on its use. If it appears as the lower-bound, it means all integers upto the upper-bound, 
	if the star is the upper-bound it means all numbers from the lower-bound and higher (to infinity), and
	if the star appears alone it means all non-negative integers. There is one additional symbol in the
	spec, the comma ',' which allows sets of ranges or numbers to be specified. Sets should always be
	ordered in increasing numerical value.

	(Whew). Here are serveral valid notation strings:

	1
	0..1
	1..*
	1,2..*
	1,3..19,20..*

	And so forth. I think that it would be relatively easy to implement some "MultiplicityValid(QString)" method
	in the dialogs, but more desirable to have a full-fledged UMLNotation and UMLNotationSet classs to aid in 
	parsing out the code.

	For example lets assume that a notation object has the last example value above ("1,3..19,20..*"), then in
	use we should beable to have methods like:

	notationObject->getNumberOfSets() returns "3"

	notationObject->getSet(1)   returns UMLNotationSet object this object has "lowerBoundValue" of 1 and 
                                                            an upperBoundValue of "NONE" (no upperbound, its just a single number, the 
                                                            NONE constant value could be defined to some negative integer like -1 or so)
	notationObject->getNextSet()   returns UMLNotationSet object (with string value "3,4,5,..,19"), calls to its
                                                            lowerBoundValue is "3" and its upperBoundValue will be "19"
	notationObject->getNextSet()   returns UMLNotationSet object with lowerBOundValue of "20" and the 
                                                            upperBoundValue of "INFINITITY" (some integer constant we should define, perhaps "-9"?)

	Of course, you should have methods to parse and validate QString to UMLNotationSet, and be able to have
	a toString method on UMLNotation and UMLNotationSet.

	Comments?

														=b.t.




--

Classical music is the kind we keep thinking will turn into a tune.
		-- Kin Hubbard, "Abe Martin's Sayings"