UML has been getting a lot of criticism from all sides, even from the modeling community. Sure, it has its warts:
- it is a huge language, that wants to be all things to all kinds of people (business analysts, designers, developers, users)
- it has a specification that is lengthy, hard to navigate and often vague, incomplete or inconsistent
- it is modular, but its composition mechanism (package merging) is esoteric and not well understood by most
- it is extensible, but language extensions (profiles and stereotypes) are 2nd-class citizens
- it lacks a reference implementation
- its model interchange specification is so vague that often two valid implementations won’t work with each other
- its committees work behind closed doors, there is no opportunity for non-members to provide feedback on specifications while they are in progress (membership is paid)
- <add your own grudges here>
However, even though I see a lot of room for improvement, I still don’t think there is anything better out there. The more I become familiar with the UML specification, the more impressed I am about its completeness, and how issues I had never thought about before were dealt with by its designers. And it seems that the OMG recognizes some of the issues I raised above as shortcomings and is working towards addressing them. Unfortunately, some fundamental problems are likely to remain.
In my opinion (hey, this is my blog!), for a modeling language to beat UML:
- it must be general purpose, not tailored to a specific architecture or style of software
- it must not be tailored to an implementation language
- it must be based on or compatible with the object paradigm
- it must not be limited to one of the dominant aspects of software (state, structure, behavior)
- it must be focused on executability/code generation (and thus suitable for MDD) as opposed to documentation/communication
- it must be modular, and user extensions should be 1st class citizens
- its specification should follow an open process
- it must not be owned/controlled by a single company
- it must not require royalties for adoption/implementation
My suspicion is that the next modeling language that will beat the UML as we know today is the future major release of UML. Honestly, I would rather see a new modeling language built from scratch, focused on building systems, that didn’t carry all that requirement/communication/documentation-oriented crap^H^H^H^Hbaggage that UML has (yes, I am talking about you, use case, sequence, instance and collaboration diagrams!), and developed in a more open and agile process than the OMG can possibly do. But I am not hopeful. The current divide between general purpose and domain specific modeling communities is not helping either.
So, what is your opinion? Do you think there are any better alternatives that address the shortcomings of UML without imposing any significant caveats of their own? Have your say.