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From Óscar Bou - GOVERTIS <>
Subject Re: Thinking about re-introducing UML in our workflow
Date Sat, 14 Nov 2015 14:49:25 GMT
Many thanks, Stephen for this detailed explanation.

The problem I’m facing is that I intent to communicate the developers what’s the model
to implement.

And I usually don’t find big mistakes in action code, but what mostly forces us to refactor
is miscommunication regarding the Domain Entities, attributes and actions names, including
typos  (think my team speak Spanish but they’re modeling in English) or wrong or missing
relationships between those entities.

All that could be avoided by firstly agree in a common UML Class Diagram.

If it can potentially generate automatically the Java skeleton with Apache Isis annotations
is a big plus, as it will avoid mistakes when moving from design to implementation.

And if it could potentially reverse engineer Java (incl. Apache Isis idioms) a really good

Any ideas about what tools could best adapt to the workflow (that could be potentially customized
to cover the last 2 whishes) ?



> El 14 nov 2015, a las 2:03, Stephen Cameron <> escribió:
> Hi Oscar,
> In a qualified way I think your idea has merit. I have never used UML for
> design, but a few years ago I decided to take a good look at it and see it
> if was useful. The idea of being able to draw a diagram and generate code
> from it seemed sensible, after all that is what is done by most other
> 'design' professions, such as building architects and engineers.
> To cut a long story short I realised after some reading that it was not
> that simple, and that OO languages themselves are really all that are
> needed for the process of designing a system. This is "the code is the
> design" school of thought, mainly attributed to Jack Reeves [1].
> I found that  keeping code and UML diagrams in sync in a top-down 'UML to
> code' design process will always be problematic (maybe why there are
> apparently no open-source tools that claim to do this). Then I read about
> Domain Driven Design which seemed to agree with this premise, and from
> there found Apache Isis via Dan's  book.
> So now for me UML class diagrams do have an after the fact use for
> documentation purposes and if a solution implement was capable of that
> reverse generation of diagrams from code it would be a good thing to have.
> Entity Framework can do this, its their "code first" approach.
> Given that the-code-is-the-design is true, I think that UML class diagrams
> real main value is as a data model, the question then is why not use a
> purely data-modeling tool and generate Java classes off it. Then the
> diagrams 'designed' could have a usefulness to programmers and to system
> users, something like those created SchemaSpy [2]  for example.
> There are already useful and free Java class generation (binding) tools
> from off data-models, of one sort or another, such as JAXB, DataNucleus'
> schemaGen[3], even CAM [4].
> Here is my vision of what I think would be really useful: to have a design
> tool that can be used by non-programmers to create a simple data-model, and
> then to have that create a working Apache Isis based CRUD system. This
> could serve your purpose (I guess) and also find a wider use.
> The means of achieving this would I think, require something like the
> "dynamic classes" in available in the Moxy framework [5], that is, map
> based so that no Java class compilation is needed. Instead, a data-model
> configuration file (a schema) is read-in to configure the system. This is
> not a strange idea, in fact its the data-driven programming paradigm that
> is the basis of the original browser concept (before it was turned into OO
> application framework via addition of Javascript). In the browser the data
> is HTML that is turned into an in-memory Document Object Model (DOM) for
> rendering.
> As a blended solution between Apache Isis as it is currently (heavily
> influence by naked objects, an OO modelling based approach for creating
> custom *behavioural* applications) and this additional mainly data focused
> approach, I think a programmer developing a business application would
> start off with these dymanic classes and then in time 'harden' the design
> by generating and compiling real Java classes from off the model. [A
> non-programmer wouldn't get past the first design 'phase' usually, but
> still end up with a useable UI.]
> In addition, by having separate abstract model-generated classes, that can
> be overwritten if the data-model changes, and concrete implementation
> classes, where you put all your behavioural code and that are never
> overwritten, you get close to the 'round-tripping' that would seem to me to
> be the only valid way to use UML *for design*. I think this is how the
> Eclipse Ecore models work, that there are model classes and implementation
> classes that extend the model classes. The IDE will often warn you when
> these two sub-models have inconsistencies. This duality also offers an
> alternative means to achieving the goals of Lombok it would seem.
> Of course, sitting in the middle of all this is a meta-model, that creates
> the dynamic classes, generates and compiles the 'hardened' model classes
> (when used) and maps either of these means to a UI 'viewer'.
> For such data-management frameworks, the complicated aspect isn't so much
> going from the designed data-model to Java, there are lots of examples of
> that, instead its being able to have also, a dynamic query capability. So
> that a person unfamiliar with the dataset, can, via its data-model, start
> querying it (and also maybe integrating it in real-time with other online
> resources, the idea of a data-browser appeals!).
> In the science domain, where I worked for a few years building
> data-management infrastructure, there are highly advanced systems for
> online data access and querying e.g. [6], but at the same time a common
> tool used for small databases is still Microsoft Access. Access has many
> strengths as a desktop database, including form generation and also dynamic
> query-by-form, but the problems arise when you want to make such data
> publicly available, in the sense of being findable and searchable in real
> time. You might as well have used a web-based system from the start and
> then been able to easily open it to the world at the appropriate time.
> Having though about this problem for a number of years and spent alot of
> time working on a XForms based solution as well. I'd be very interested to
> see Apache Isis broaden its scope to offer what I have described, in fact
> its doesn't seem to need very much more than what is already present in the
> Isis meta-model and Wicket viewer. The Restful objects support already
> provides a generic 'generated' web programming interface.
> In summary I know that there are some Java projects that make very
> effective use of a Model Driven Architecture approach (e.g [7]), but I am
> now not sure that UML is the 'be-all-and-end-all' basis of that. Actually I
> think that data-models are the basis of most of MDAs efficiency dividends
> and that there are other approaches, specifically that conceptual models
> offer more versatility in terms of who and how you can make use of them.
> This thinking goes way back, such as Sowa's Conceptual Graphs [8] and even
> to Codd [9]. A modern expression of Sowa's thoughts (I gather) is the W3C
> semantic web, but he was thinking of database design and query way back.
> Apart from some additions to Isis, another interesting aspect is looking at
> the mapping to data-stores, using a graph database of one sort or another
> to avoid the complexity of ORM is a simple answer to that I feel. Again,
> the hardening of a design might mean manually adding a few overrides of
> default ORM mapping rules into some behavioural-model classes, that extend
> generated data-model classes (getters and setters only).
> [1]
> [2]
> [3]
> [4]
> [5]
> [6]
> [7]
> [8]
> [9]
> On Fri, Nov 13, 2015 at 8:45 PM, Óscar Bou - GOVERTIS <>
> wrote:
>> Hi all.
>> I’m considering re-introducing UML Class diagrams in our workflow mainly
>> for:
>> - graphically design the domain entities.
>> - modeling relationships.
>> - agree with names of properties, collections and actions needed.
>> It would be wonderful if the UML solution could also be “integrated” with
>> Apache Isis or Java, automating at least the entities Java skeleton
>> generation.
>> I’ve worked extensively with Rational Rose and Sparx EnterpriseArchitect,
>> but was thinking about an Eclipse-based solution that could “potentially”
>> be adapted to generate the Java entities with Isis annotations.
>> Before joining the Apache Isis community I developed [1] for Enterprise
>> Architect for automatically generating Spring Roo-based classes, but Isis
>> was better suited for our project and I abandoned it.
>> Any ideas?
>> Thanks,
>> Oscar
>> [1]

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