stuart kent's blog

Is Model Driven Development Feasible?

2011-04-07T11:41:24Z

This is the question asked in the title of a post on our modeling and tools forum, and rather than answer directly there, I thought it would make more sense to post an answer here, as it’s then easier to cross-reference in the future.

The body of the post actually reads:

Various Microsoft attempts at MDD have failed or been put on the back burner: WhiteHorse, Software Factories, Oslo.

Does Microsoft have any strategy for Model Driven Development? Will any of the forementioned tools ever see the light of day?

First we need to clarify some definitions. I distinguish between the following:

Model-assisted development, where models are used to help with development but are not the prime artefacts – they don’t contribute in any direct way to the executing code. Examples would be verifying or validating code against models or even just using models to think through or communicate designs. UML is often used for the latter.

Model-driven development, where models are the prime artefacts, with large parts of the executing code generated from them. Custom, hand-written code is used to complete the functionality of the software, filling in those parts which are not represented in the model.

Model-centric development, where models are the prime artefacts, but interpreted directly by the runtime. Custom, hand-written code is used to complete the functionality, with an API provided to access model data and talk to the runtime as necessary.

These are not separated approaches, and development projects may use a combination of all three. In fact, I imagine a continuous dial that ranges from model-assisted development through to model-centric development, such as the one illustrated below (starting at the left, the first five tabs are examples of model-assisted development).

The challenge is to make the movement through the dial as seamless and integrated as possible, and also to make sure that these approaches can be adopted incrementally and in a way that integrates with mainstream development (agile) practices. Only then will we be able to unlock the potential productivity benefits of these approaches for the broader development community.

In Microsoft, there are a number of shipping products which support or employ one or more of these approaches.

In Visual Studio, we have DSL Tools and T4, which together support model-driven development. New functionality was added to both in VS2010, and T4, for template-based code generation, continues to see broader adoption, for example in the ASP .Net community as evidenced by this blog post. for example. Many customers use DSL Tools for their own internal projects, and we continually get questions on this forum and through other channels on this.

Visual Studio 2010 edition introduced a set of architecture tools: a set of UML Tools (built using DSL Tools), a tool for visualizing dependencies between code as graphs, and a tool for validating expected dependencies between different software components (layers). I would place all these tools under the category of model-assisted development, although the VS2010 feature pack 2 does provide some support for generating code from UML models, which allows these tools to be used for model-driven development, if MDD with UML is your thing.

Visual Studio LightSwitch combines a model-driven (generates code) and model-centric (directly interprets the model) approach to the development of business applications. It is a great example of how models can really make the developer more productive.

Outside of Visual Studio, the Dynamix line of products, also take a combined model-centric/model-driven approach to the domains of ERP and CRM business applications. For example, take a look at this blog post.

I am an architect with the Visual Studio Ultimate team, who are responsible for DSL Tools, T4, and the architecture tools. In that team, we are now looking into how to take these tools forward, focused very much on how to make software developers and testers more productive. Part of this will be to consolidate and integrate some of what we already have, as well as integrate better with other parts of Visual Studio and mainstream development practices. Another part will be to add new features and capabilities and target support on specific frameworks and domains – as LightSwitch does. We’re focused on addressing the challenge set out above, and to deliver value incrementally.

As we start to deliver the next wave of tools, I look forward to a continued conversation with our customers about the direction we’re headed.

Addendum (8/4/2011): I forgot to mention that another problem we’re currently focused on is how deliver a much more seamless integration between models and code, which is essential to meet the challenge described above.

Sprinkling the MEF fairy dust on DSLs

2010-05-25T09:19:17Z

We’ve been enjoying injecting MEF extension points in our tools to make it easy for customers to write extensions using very simple code. Jean-Marc has just posted a sample demonstrating how MEF-enable your own DSL so you too can add MEF extension points for customers. See http://blogs.msdn.com/jmprieur/archive/2010/05/17/enabling-your-dsl-for-mef-extensions.aspx for details.

Useful blog on VS2010 Architecture Tools

2010-05-25T09:17:26Z

Cameron Skinner has recently been on tour in the US giving talks about the new architecture tools in VS2010. He was touring with a developer evangelist Jennifer Marsman, who has followed up with a load of informative blog posts giving more detail on teh material that Cameron presented. A good entry point is http://blogs.msdn.com/jennifer/archive/2010/05/10/visualization-and-architecture-tools-in-vs2010-cameron-skinner-tour-summary.aspx.

Extending UML sequence diagrams to cover LINQ

2010-05-25T09:13:58Z

Just catching up on blog reading and came across this post from Cameron: http://blogs.msdn.com/camerons/archive/2010/05/08/sequence-diagram-re-linq-and-lambdas.aspx

It gives the details of of a small extension to UML sequence diagrams introduced in our VS2010 implementation to cope with deferred execution of LINQ expressions. And gives a real insight into the lazy execution strategy used for LINQ expressions.

Tech Days UK videos now available

2010-04-27T15:26:03Z

Videos of the VS2010 launch and deep dive sessions at the recent Tech Days UK event are now available. Also See my earlier post about this event.

Goto http://www.microsoft.com/uk/techdays/ click on the Resources tab and then choose the video you’re interested in watching.

I’ve embedded the video of my session below:

Tech Days in London

2010-04-14T07:10:06Z

Writing this as I come back from speaking at Tech Days in London, in a series of deep dive sessions following the launch of VS2010. The venue was a cinema in Fulham Broadway. The place was full (between 500 and 600 people), indeed over-subscribed. I understand that some folks who turned up were turned away (Health and Safety dictates that you can’t go over capacity in this kind of venue); desperately sorry for those unlucky few, but perhaps they enjoyed a day in London instead. It’s great to see so much enthusiasm for the new tools in Visual Studio. Yesterday’s VS2010 launch was packed out as well.

The decision to use a modern cinema was inspired. The seating is very comfortable, much better than you usually get in conference centres, and I think this must be the largest screen I’ve ever given a presentation on; there were no worries about people not being able to see the text. Though slightly disconcerting to see a few participants tucking into their popcorn! The audience was attentive, and I could see some heads nodding in the front rows, with, of course, the usual politeness and reserve to be expected from a British audience. I’ll be interested to see the feedback scores. A couple of questions: one asking about the version of Visual Studio you need to use these tools (Ultimate for all the functionality, though some limited functionality is available in lower versions), another about the relationship to M and Oslo (M is now part of SQL Modeling Services, and we look forward to being able to hook some of our visualizations to models in databases at some point in the future).

The speaker after me was Colin Bird, formerly of Conchango and now founder of a new company RippleRock. He gave a very interesting talk on Agile Development, making the point that Microsoft is really providing a tooling platform, with some tools, templates and so on in the box to get you started, but to get the most out of it you need to invest some resource every sprint into building up and maintaining your tools and automation, which should include customizing and extending Visual Studio to fit your own engineering practices and particular circumstances. I couldn’t agree more, and I think that it is our job in Microsoft to make it as easy as possible to implement and deploy those customizations. As an illustration of how far we’ve come, towards the end of my talk I was able to create a new extension to the UML designers and deploy it to VS in less than a couple minutes, as well as create a new DSL from scratch. A few years ago, I’d have been much more careful about demonstrating DSL Tools because of the wait times it took to do the code generation and build. Deployment was also a case of adding another project to create a .msi. And I wouldn’t have dared tried creating other kinds of VS extension during a demo.

This trip also made me realize how old I must be getting (that and the recently acquired reading glasses). I used to live in London when a PhD student, and would have expected to have needed to go outside at least once to get to my destination. I travelled on the high speed rail service from my home town of Canterbury which takes you straight into St Pancras station. It’s the first time I’ve used this service (I usually take the slower train into Charing Cross), and I have to say that St. Pancras really is beautiful, with a broad arching roof over the platforms. So I arrived under cover, and from there you can walk to Kings Cross tube without stepping outside, then round on the Circle line to Edgware Road, and a step across the platform onto the District line service to Fulham Broadway. The entrance to Fulham Broadway is integrated into the shopping complex and multi-screen cinema, so no need to go outside there, either. The experience was slightly surreal.

Interesting case study in using VS2010 architect tools

2010-04-12T21:10:09Z

Just came across this. Check it out: http://www.microsoft.com/casestudies/Case_Study_Detail.aspx?casestudyid=4000006781

VS2010 Visualization and Modeling SDK

2010-04-12T18:05:44Z

It’s great to see that the RTM version of the Visualization and Modeling SDK is also available at the launch and release of Visual Studio 2010. For details check out http://code.msdn.microsoft.com/vsvmsdk. See also Jean-Marc’s announcement of this.

As well as the DSL Tools which has been much improved in this release (see What’s new), it also includes some project templates to get you started with extending the UML Tools in Visual Studio. Enjoy.

Visualizing work item graphs in VS2010

2010-04-12T12:26:52Z

In Visual Studio 2010, released today, there is a new visualization tool which, in-the-box allows you to generate a quick graphical view of your code, amongst other things. Chris Lovett was a key architect of this tool, and has some great blogs about it’s features and how to get the most out of it. See http://www.lovettsoftware.com/blogengine.net/

The tool visualizes data expressed in a markup language called DGML, which means you can visualize any data which can be rendered in this form. I’ve been using it internally to help understand the wealth of project management data we have stored as work items in TFS. In particular VS2010 supports typed relationships, which means you can express much richer information about the relationships between work items, which is great, except that it can be difficult to track what’s going on even by using tree-based queries. So being able to visualize the work item graphs as graphs is a real boost. It’s great, then, to find a project on codeplex which shows you how to visualize your TFS work item data using DGML: http://visualization.codeplex.com/. A screenshot is given below.

If you think this would be useful to you, you may like to think about other ways of visualizing the data. One thing we’ve managed to do is group stories by area rather than iteration, and then create a graph per iteration which is filtered only to show the stuff for that iteration, as well as a graph that spans all iterations, or some appropriate subset. Then you can nest tasks under stories, and use colouring to indicate % completion of tasks, which can also be aggregated up to stories, and then up to feature areas containing the stories. If there are no tasks, then the estimates against the stories are used to calculate completion and amount of work remaining. This allows us to see, at a glance, how much we’ve completed per sprint and at any time in the sprint, as well as for the whole project.

VS2010 – Useful links on getting started with ALM features

2010-04-12T11:52:27Z

I just came across this post from Charles Sterling with a bunch of useful links:

http://blogs.msdn.com/charles_sterling/archive/2010/04/09/getting-started-with-visual-studio-2010-alm-features.aspx