Heiko Behrens (Blog)

Video Compositing on the iPhone: OpenGL with alpha mask on top of a full motion video

Heiko Behrens — Wed, 07 Jul 2010 13:50:41 +0000

During the iPhone game project I have written about before we had to implement a highly dynamic 3D scene in great detail here at itemis. From a third-person perspective, the player looks at a semi-transparent ball rolling through a gully towards a waterfall. To implement this with the limited resources of the mobile device we came up with an adaption of the rear projection technique as known from film productions.

The game screen has been built with a full motion video behind the HUD and the game layer.

The game screen as seen by the player internally consists of different layers. The top-most layer contains 2D graphics and displays information such as speed or remaining time. Behind this layer (or plate) the dynamic 3D game scene is being rendered. This layer contains the actual game elements the player controls. It has been built with OpenGL and displays the player’s character inside a rolling ball.

Now, in addition to this quite common setup we implemented a third layer in the back that plays a full motion video of a pre-rendered game scene. Even though this technique had been used for games such as Rebel Assault on the PC between the late 80’s and the early 90’s I am not aware of any iPhone game that integrates the game layer as tight as we did with matting and alpha compositing.

Game elements (a) with animated matting (b) appear inside (c) or even "behind" a background movie as illustrated on (d).

In no case we wanted to deliver a separate, affixed game layer above the movie. Instead, we tried to create the impression of embedded game elements (a) as an integrated part of the pre-rendered movie. With the help of an animated alpha mask (holdout matte) that corresponds to the wave movements of the river (b) we were able to let the water appear above the ball (c). And by using a matte with a true alpha channel we were even able to let submerged parts of the scene shine through the water surface as you can see on (d).

NIVEA FOR MEN WaterfallRace is available on the App Store for free and I will write another post including a screencast once the scheduled update for known bugs is out.

We were able to make this compositing feature work on the 1st generation iPod Touch and iPhone with the SDK 3.0. Please let me know if you are interested in the technical details on how to configure the EAGLView and MPMoviePlayerController or how to sync with the movie on the targeted iPhone OS 3.1. Also, please comment on this post if there’s another development aspect of this project you want to learn more about.

Psychologically Tricked: Perceived Speed in an iPhone Game

Heiko Behrens — Thu, 03 Jun 2010 12:00:50 +0000

In a recent iPhone game project I was involved with at itemis the player had to gain speed by tapping on the touch screen. Several game elements conveyed the impression of acceleration to motivate the player achieving this goal. The 3D game graphic of fly-by elements in a canyon were supported by a crescendo of game sounds and as with any serious racing game there was a speedometer, too.

Update: Read the follow-up post about the NIVEA FOR MEN WaterfallRace.

Different functions to separate actual and displayed speed values

During our first phase of interaction tests we constantly got the feedback that the speedo was not accurate, though. Players had the impression to be way faster than the value displayed by the gauge. Others complained about how hard it was to gain speed in the lower region.

We decided to separate the actual speed used for game logic from the displayed value as shown by the speedometer. The paper “Rethinking the Progress Bar” I stumbled across a while ago when I was improving the user experience of a desktop application came in handy to do so. Chris Harrison et. al. discuss how different update rates of ordinary progress bars change the user’s perception of progress duration. They come up with some simple, yet useful functions to map a real progress value x to the displayed value f(x).

Selection of functions as described in Rethinking the Progress Bar

Whereas the results in the paper highlight functions that produce an accelerating progress bar in the end we needed to achieve the opposite for our game.

My speed is quite good by now but I am not at top speed, yet. I will try harder.

On slow speed ranges our speedometer simulated a higher speed and greater variation on speed changes. Beginners got immediate feedback and felt success that way. High speed values on the other hand were visually more difficult to achieve. That behavior seemed to motivate advanced players.

We first used the Inverse Fast Power function but eventually settled on Late Pause. No player ever mentioned a mismatch between the actual and the displayed value after our adjustments and nobody seemed to recognize the fake.

Links

Preview your photoshop design directly on the iPhone/iPad

Heiko Behrens — Fri, 07 May 2010 20:19:51 +0000

Too many screen designers are not yet familiar with mobile touch screens. There, you have to look carefully for buttons large enough to hit with your thumb, fonts that are readable on the go and colors that compensate those energy-saving displays. As with print, you should proof your design against the actual output early and regularly. But since we are in the 21st century we can choose a more effective way than using color calibration, DPI adjustments, or print-outs to do this.

A week ago I stumbled across a small and free tool by Nicholas Zambetti called LiveView you can find on the App Store. Its concept is easy: On your Mac you run the LiveView ScreenCaster. That counter part renders an iPhone/iPad frame in its actual (huge!) dimensions on your monitor. Anything that shines through the screen of that imaginary device is being sent over the Wi-Fi. On the iPhone/iPad you can now run the LiveView app. It automatically finds every Mac currently running a ScreenCaster via Bonjour, asks you for the one to display and… Well, that’s it. You can now see your screen pixel perfect without exporting and importing images anymore.

Get a live copy of your screen on the iPad with the LiveView app.

As it turns out, this is just the way you can immediately test out anything you mock on your big screen. The ScreenCaster frame gives you the right idea about the actual dimensions of the device including its borders. You can adjust its position pixel by pixel with the cursor keys and finally press CMD+H to hide it. This is far more convenient than any VNC-based approach I tried before.

From there, work with Photoshop, Pixelmator, OmniGraffle or any other tool as usual. You can hide layers, resize elements, and change your font size while watching everything live on your device.

Impress your client and hand over the iPhone to your stunning audience while swapping layers. Or, use the tool as I did it with my current project at itemis. I looked at a flash website through the iPhone! That way, I was able to gain a first impression of what can be improved with a true iPhone app.

Unfortunately, the ScreenCaster cannot be rotated to send the data in landscape mode. Another flaw is the lack of a Windows version of the ScreenCaster. Nicholas, if you read this: I meant it the way I mailed it. Let me know if I can help you with the Windows port!

Let’s get naked

Heiko Behrens — Fri, 09 Apr 2010 07:37:24 +0000

Today is CSS Naked Day 2010, hopefully many websites will participate and deactivate their styling as I did with this blog. The idea behind CSSND is to promote web standards and proper, semantic markup.

This blog with and without Cascading Style Sheets on the CSSND.

In my opinion web standards such as Cascading Style Sheets (CSS) tremendously evolved over the last years. Where I used images and tables years ago in order to achieve a proper site layout I can simply use CSS nowadays. In my current project I go even forward and implement transitions, rotations and semi-perspective alignment in a consistent, declarative way.

For a single day, I will deactivate CSS to honor these achievements. Thank you – Håkon Wium Lie, the W3C and the early adopting web community!

The iPad sucks – my first impressions

Heiko Behrens — Wed, 07 Apr 2010 15:25:54 +0000

Now that I got your attention, read on and understand what exactly I dislike about the current version of the iPad. In short: its weight, the curved flip side while typing, the reflecting display and the absence of multi-user support. So, what does this mean to me?

The iPad after 15 minutes of usage

Weight and Typing

When I held this device in my hands this morning my first reaction was “oh, that’s heavy”. And in fact, after holding it a few minutes between my thumb and forefinger while swiping and touching through the apps this impression got stronger. Its weight becomes even more annoying while typing when you hold the device with one hand and type letter by letter with the other one.

“Not a problem” you might say, “one can place it on the table to type”. Well, yes and no. I was suprised how stable it was on the tabletop despite its curved flip side. The keys are way larger than those on the iPhone and typing with two hands would be a pleasure if there wasn’t the space bar. Each time I hit the spacer with my thumb the device slightly revolved around its own axis. Only cloth could prevent this.

“Why not using two thumbs for typing”, I thought by myself. This is what I do on the iPhone the whole time and it might work well on the iPad even though it’s larger. I was looking at the virtual keyboard to hit the proper keys with my thumbs and kept quite happy for a few letters. To conquer those larger distances with your fingers is one thing. To focus text and keyboard with my single pair of eyes simultanously simply doesn’t work. The keyboard at the bottom and text at the very top of the screen are so far away from each other on that huge display, this technique doesn’t work anymore. The seesaw between text and keyboard made me feel like I haven’t typed before at all.

In the end, only few postures on the sofa where you place the iPad on your lap worked fine for me.

Glossy Display

At first glance, this might only be an esthetic issue. Having finger prints all over the display is not really the end of the world. It’s just in the eye of the beholder. Right, but having reflections of your ceiling light, sunblinds or windows in general is more than annoying. When one finally found a way to type successfully on the iPad, there are not many options to prevent those reflections anymore. There’s no turnable display lid like the one on your laptop and you cannot easily change the angle between your tables and your windows – once you figured out how to type with two hands.

No Multi-User Support

I think of the iPad as the obvious extension of your living room. Your guests can look-up the soccer results, browse on youtube, pass it around to complete the pizza ordering or even check their facebook status. And the latter is exactly the problem with the iPad. As anything else in your living room the iPad is open to anyone. But what about your mails? What about your browser history and your stored logins? And what about your beloved calender, twitter, facebook or baking apps that grant access at a single finger tip?

Do you really have to lock the iPad? Is it just a toy and must not be used for serious data?

Conclusion

I am still fascinated by the iPad. It’s an amazing (some argue “magical”) piece of technology. I will get used to its weight and will learn how to type and look at the glossy display. But the lack of a “guest profile” or an equivalent way to hide away sensible data is something apple has to work on. Under these circumstances there’s only one option for me to use the iPad in future – I will need two of them.

The iPhone at EclipseCon 2010

Heiko Behrens — Wed, 31 Mar 2010 08:49:36 +0000

The EclipseCon 2010 was a huge success not only for our flagship project Xtext. As mentioned by Sven and Jan before, we gratefully received the Eclipse Community Award and enthusiastically delivered more than 6 talks around model-driven software development. But beyond that, it’s been the first international conference where you could learn about a new area of itemis’ activities: mobile applications.

100% Generated iPhone app of my EclipseCon talk

During my talk on Monday (slides on slideshare), I argued how you can leverage the ideas of MDSD to be more efficient when building iPhone apps with the help of domain-specific languages. To prove this, I built a running iPhone application in front of the audience in just 12 minutes. That application was able to browse the corporate blog of itemis as well as an index of itemis speakers and talks available at EclipseCon. From any screen you could jump to related bits of information. Everything was being loaded on demand and behaved like every other native application on the iPhone – since it is a native app. And the coolest thing: All this without leaving Eclipse!

As you can read in the interview I gave to The Bitsource I understand this particular demo app as an example. It represents an important part of many apps you can find in the stores today and the provided results are substitutional for the whole group of data-centric mobile applications itemis is going to deliver with the powerful help of MDSD.

Me holding the iPhone Mars Rover app. Click the image to watch a video of the iPhone Mars Rover app.

A rather unusual event we stumbled upon was the EclipseCon Mars Rover Challenge held in cooperation with the NASA JPL. It’s idea was to create the very best robotic control system to drive a robot across a prototypical Mars landscape. And guess what? Peter and I set out to deliver an iPhone application to do so.

To make a long and amusing story short, we came up with a vibrating and blinking iPhone app that allows you to steer the robot by tilting the device. Popular Science, Mashable, Slashdot and many other news sites caught up quickly – so we decided to publish a dedicated website (iPhoneMarsRover.com) discussing the details and providing more images on that particular application. At this point I want to thank Carsten and Michael for their invaluable help building that site. It’s a pleasure to work with such talented people.

And regarding the Mars Rover app: In future, we will most probably give droids the chance to hold that app in their hands – stay tuned!

Yes, itemis truly enters the market of mobile applications. And this goes way beyond ordinary iPhone, Android or Symbian apps. We are currently working on something that will knock your socks off! But that’s still a #secretproject…

Update 04/15/10: Dzone interviewed Peter and me about the aforementioned talk as well as the Mars Rover app. Read more details over there.

Recent updates of the Xtext website

Heiko Behrens — Thu, 07 Jan 2010 18:27:08 +0000

In conjunction with the Eclipse M4 release of Xtext its website has been updated, too. We wanted the new features to reflect how lively the Xtext project is by just looking at the website. At the same time, they should not scare away new visitors but be informative and subtle.

In the end we came up with: Some statistics of the project activity (1), a news aggregator (2), and a condensed (53 secs) introductory screencast (3).

The updated Xtext website displays commit statistics (1), recent blog posts plus other web content (2) and a brand-new introductory screencast (3)

Our project website attracted some attention since it has been launched this June. The AMP project reuses its layout and Denis from the Eclipse webmaster team embraces the results, too. From there, the bugzilla 235828 discusses whether the Xtext website should serve as the standard template for new Eclipse projects.

Currently, you can see such an “empty Xtext website” at eclipse.org/default - how cool is that!

The Bells and Whistles

Even if Denis, Matt & Karl will provide a standard template based on the Xtext website you might want to adapt some of our additional features, too. To support you in doing so, I will summarize the underlying technology of the recently introduced features.

To produce the commit stats (1) the page leverages the commit statistics of Xtext and renders the polished data with the Google Chart API on order to match our visual expectations.

The news section has been built with Yahoo Pipes to scan, filter and aggregate different web resources asynchronously. You can even subscribe to the news feed directly to always stay up to date.

For both the commit stats as well as the news section Denis allowed me to install a cronjob that fetches and stores the results independently from the http requests.

The screencast has been recorded and edited with ScreenFlow. Also, thanks to Sven for the audio equipment!

Let me know if you want me to provide more details.

Retrospection of the iPhone Developer Conference 2009

Heiko Behrens — Mon, 07 Dec 2009 20:11:49 +0000

The German iPhone Developer Conference in Cologne (01-02 December) was an exciting event that started with a very informative keynote by Maximilian Reiß who elaborated the tide of iPhone events of the last years. From there, nearly 200 attendees were invited to join business-related presentations and developer-oriented talks on separated tracks over the next two days.

Nearly 200 attendees, 29 talks on 2 days and 3 winners of the best German iPhone App contest at the iPhone Developer Conference in Cologne

I had the chance to introduce the iPhonical project that applies model-driven techniques to produce parts of iPhone applications automatically. The presentation first describes a way to separate generated code from manually written source with the Objective-C concept of categories. From there, I demonstrated that even with powerful frameworks such as ObjectiveResource (an adapter to connect iPhone apps with Rails applications) one can benefit from code generation. With the help of the iPhonical DSL (implemented with Xtext) keeping data-centric classes in sync with the web application was way easier than coding them by hand.

The iPhoneDevCon was a very informative event. Many passionated developers or leads, growing studios and enthusiastic marketing representatives shared their ideas and during the breaks you could easily discuss different viewpoints of today’s opportunities and approaches.

Apart from the 3 winners of the “best German iPhone app” (according to iPhone & Co) a brand-new iPhone and Mac magazine, mac-developer, has been announced. As the name suggests it concentrates on developers and its first issue is quite promissing.

iPhonical at the second German iPhone Developer Conference in December 2009

Heiko Behrens — Sun, 25 Oct 2009 17:33:33 +0000

This December will start with two exciting days when the German iPhone Developer Conference takes place in Cologne. With 28 talks about business and engineering on two tracks the second iPhoneDevCon celebrates the second anniversary of the iPhone itself. Not by accident Maximilian Reiß picks up this coincidence and gives a résumé of two eventful years with apple’s successful device in his keynote.

My talk about model-driven iPhone development in general and the open source tool iPhonical in particular ranks among many other promising talks for developers.

Visit the German iPhoneDevCon in Cologne on December 01-02, 2009

If you are planning to attend please contact me in advance. Being a speaker I can give away a limited amount of promotion codes. This might safe you some expenses and allows you to buy me a drink in return

EWiTa 2009 in retrospect

Heiko Behrens — Sat, 24 Oct 2009 10:42:48 +0000

Yesterday’s first Elmshorner Wirtschaftsinformatiktag at the Nordakademie was a worthwhile event. As expected, the lineup arranged by Hinrich Schröder and Frank Zimmermann motivated controversial discussions. Hartmut Herde asked critical questions about MDSD whereas I outlined how MDSD can be applied successfully with the needed knowlege at hand. Anyway, I fully agree with his opinion and enjoyed listening. Try to read his paper in the proceedings if possible.

Frank Zimmermann explained how Eclipse Modeling and Xtext in particular can be used to produce SAP applications. He even gave a live-presentation of the tools his students developed during a research project.

Simon Zambrovski took some photos at the EWiTa

Since the slides I used at the EWiTa were an excerpt from a former talk at the Code Generation 2009 in Cambridge I will only list the related talks I mentioned in the end:

Xtext Workshop
Eclipse Summit Europe – 27 October 2009 – Ludwigsburg
Mastering differentiated MDSD Requirements at Deutsche Börse AG
W-JAX 09 - 10 November 2009 – Munich
Experience Report by Deutsche Börse AG
Eclipse DemoCamp Frankfurt – 26 November 2009 – Frankfurt
Combining Graphics and Text in Model Editors
Eclipse DemoCamp Hamburg – 04 December 2009 – Hamburg

Eclipse Modeling Days 2009 in New York and Toronto

Heiko Behrens — Tue, 20 Oct 2009 17:27:48 +0000

This November you are invited to learn more about modeling with Eclipse at the Modeling Days in New York (November 16th) and Toronto (November 18th). Both one-day long events will get together experts of different modeling domains and will give you the chance to get in touch with them.

Meet us at the Eclipse Modeling Days in New York and Toronto

Personally, I am looking forward to the talks

“Modeling on an Enterprise Scale” (read: “Learn more about CDO”)
by Eike Stepper and
“Agent-Based Computer Simulation for Operational Risk Analysis”
by Ed MacKerrow

to learn more about two exciting topics I am curious about. Of course, itemis will be there as well. Make sure you don’t miss

“Converging Textual and Graphical Editors”
by Moritz Eysholdt and
“Building DSLs with Xtext”
presented by myself.

Head over to the wiki page to browse the abstracts and register for one of these free events or read some other announcements.

Looking forward to seeing you over there!

Focus on Modeling at the first Elmshorner Wirtschaftsinformatiktag

Heiko Behrens — Wed, 14 Oct 2009 21:20:46 +0000

On Friday, October 23rd the first Elmshorner Wirtschaftsinformatiktag near Hamburg will open its doors to elaborate on the topic “Modeling the Business”. I will give a talk about some best-practices itemis applied in MDSD projects based on Eclipse Modeling. An ongoing project at Deutsche Börse AG offers insights in how even established and widely known modeling techniques such as UML or code generation can be optimized with some pragmatic adjustments.

Elmshorner Wirtschaftsinformatiktag at Nordakademie near Hamburg

Other talks such as

“Collaborative Modeling of Business Processes” (Mathias Weske),
“Test-Driven and Model-Driven combined with openArchitectureWare” (Arne Michael Törsel) or
“Being Skeptic about MDSD” (Hartmut Herde)

show great promise for interesting discussions. Please note that the aforementioned talks as well as every other talk will be held in German (I freely translated the titles for you).

There’s no conference fee and the organizers will be happy to welcome you at the Nordakademie if you register before October 23rd. So, if you happen to be around Hamburg that Friday don’t miss the 1st EWiTa!

Burlington Ducky iPhone App

Heiko Behrens — Fri, 02 Oct 2009 07:32:52 +0000

The people at itemis provide a vast range of skills beyond model-driven engineering. For me, this versatility yielded an iPhone project in cooperation with Weischer Mobile and phi mobile media where a funny marketing app had to be delivered. The design concept presented to Burlington drafted a line (water), a circle (duck) inside a rectangle (iPhone) and an arrow (movement). Some bullet points completed the requirements of the part I was asked to implement. Even though the final app offers some more features such as a movie, funny photo tricks and wallpapers, I was responsible for the ducky only. This is what I came up with:

Under the hood, the animated ducky as well as the illusion of water is based on a hand-crafted physics engine. The water is implemented as a particle-based fluid simulation. Matthias Müller published a paper with the same title and great slides for SIGGRAPH 2007 as a starting point if you are interested in this topic. The ducky itself interacts as rigid body with these particles where buoyancy had been implemented explicitly. Play with Erik Neumann’s demo to have fun with rigid body physics. These concepts had been adjusted and combined with the accelerometer and touch sensors built into the iPhone to let the user interact with the simulation.

Different techniques had been applied to realize the illusion of a splashing ducky

Having just dots and circles as one could look at the physics engine was obviously not the ultimate goal. From the raw data of the simulation the water surface area had to be derived, the ducky had to be put in shape and some smooth animations and sounds were needed to round out the illusion of an interactive bathtub.

Without going into every detail I want to emphasize that the iPhone is not a MacBook Pro. Where you traditionally use marching cubes/squares to convert distinct particles into a cohesive area the processing power of mobile devices requires you to squeeze out every cycle by thinking outside the box and taking advantage of hardware acceleration. In this case, OpenGL ES offers a variety of techniques including framebuffers, blending functions and alpha tests to perform the needed steps by the GPU.

metaball technique from particles using blending and alpha functions

Some other findings during the project include the unreliability of sensor data as well as users’ unpredictable behavior. Be aware that humans and machines act differently under certain circumstances. For applications where the interaction between those both is crucial you should do usability tests early, often and extensively before delivery, again.

The iPhone is different from other mobile devices or the emulator. Generally, floating point arithmetic will be evaluated more efficient than fixed-point. Some GPU operations are executed faster on the device than on the emulator, others are of poor performance though. Therefore, you should profile on the device to test different approaches of your design regularly. And: You must not forget to do so with sound enabled since sound processing might take more than 30% of your overall processing power.

So, go ahead and grab your version of the Burlington Duck on the app store:

If you are interested in details (e.g. “unpredictable human factor”, production of the screencast, etc.), please let me know and use the comment function of this post.

Profiler for Xpand/Xtend/Check

Heiko Behrens — Fri, 25 Sep 2009 10:27:16 +0000

A polished version of the announced profiler will be part of the upcoming 0.8.0 M2 release of Xpand next Tuesday. It acts as a callback for any expression-based workflow component to measure the execution times of Xpand templates, Xtend functions and Check validations. Also, it constructs a call-graph model to introspect callers and callees and their corresponding call times. From this model you can then generate an HTML report as part of your generator workflow.

Output of the profiler from the Xpand Sample-Project

If you stay with the text-based GProf output format (another option to dump the collected data) you can also use tools like Gprof2Dot to visualize hot spots with colors and callees as painted connections.

Same workflow visualized with Gprof2Dot without reduction of nodes with no impact

The updated documentation explains how you can integrate the profiler into your workflow. Also, the Xpand Sample-Project Wizard creates a second workflow “generatorWithProfiler.mwe” where I have generated the above results from.

In a real-world project we were able to reduce the execution time of a workflow that originally took nearly half an hour down to less than 3 minutes using an earlier version of this profiler. It can also help you detecting unwanted indirections and recursions.

openArchitectureWare working group at Eclipse

Heiko Behrens — Mon, 21 Sep 2009 09:31:22 +0000

Over the weekend we have finally announced openArchitectureWare’s move to Eclipse at the respective websites. You will now find a landing page at openArchitectureWare.org that announces the move. The letter of intent summarizes the ideas behind the move for the loyal oAW 4 community.

openArchitectureWare moved to Eclipse

The homepage of the working group at Eclipse offers links to ready-to-use distributions and we are working on update sites, too.

I want to thank Peter and Karsten for their help with this. Hopefully, this public notice will encourage even more users to migrate to the more stable and feature-rich version at Eclipse. Again, if you need professional support around oAW itemis will be glad to assist you.

Xtext goes SAP

Heiko Behrens — Fri, 11 Sep 2009 09:26:31 +0000

In a recent cooperative project between the Nordakademie, cimt AG and itemis AG we explored the possibilities of model-driven approaches in combination with domain-specific languages in the field of enterprise software (read: SAP). A group of nine students used Xtext and other Eclipse modeling components to express bid estimates of ocean carriers to derive and deploy database tables, Dynpros and ABAP code with a one-click solution.

MDSD process shortens development cycles where the customer expects specific applications to calculate different classes of estimation bids

My work as the “technical facilitator” was mainly enjoying the progress and providing alternatives during the sprint review and planning meetings (yes, the group decided to go with Scrum). Without excessive help the students were able to develop a DSL that is able to

make simple and complex existing data types of the SAP system available to the editor,
express business formulas based on variables of these types,
provide a comfortable editor that checks many constraints and guides the expert, and
describe layout of the UI based on these values.

From this input some Xpand templates generate

a testbed for these formulas that allows domain experts to capture their expectations within a spread sheet application,
database table descriptions to store estimates for reference,
a dynpro frontend including search masks to fill in the needed dimensions and displaying results in real-time, and
the needed ABAP code to perform the calculations as well as glue code for the SAP system.

Prof. Frank Zimmermann published a short description of this project in the in-house magazine Capusforum of the Nordakademie (German). There will be more material on these results soon: The students are preparing a publication addressing MDSD for Enterprise systems in a larger German magazine. The cimt AG and itemis will use this project to demonstrate the possibilities as well.

For me, this research project is just a proof of concept. I am sure the vast majority of SAP projects can benefit from MDSD principles. Thanks again to Prof. Zimmermann from the Nordakademie, Michael Neuenstadt, Michael Flemming as well as Dr. Kuhlmann from cimt AG and last not least the students. It was a pleasure to work with you!

If you have detailed questions -technical or commercial- don’t hesitate to contact me or the responsible sales representative, Asaf Ikram.

Detect erroneous white spaces with Hex Fiend

Heiko Behrens — Thu, 03 Sep 2009 12:13:47 +0000

Recently, a colleague of mine received a small patch via email to apply it with Eclipse. To our both suprise the version that worked perfectly for me lead to syntax errors in his side. The patch seemed to be ok and so did the resulting Java code – apart from the syntax error.

Can you explain this Java error with an ordinary text editor?

For some unexplained reasons one of the spaces (0×20) had been replaced with another character (0xCA) which looks perfectly in any text editor but forces Eclipse to stop with an error. This might be connected with a common mistake I am doing regularly when switching between different types of computers is hitting + on my Mac. This produces an “erroneous white space”, too!

Hex Fiend is a sophisticated hex editor for Mac with many handy features.

Meanwhile, I am using Hex Fiend to quickly analyze Java code with such errors but also to look into arbitrary binary data. It allows you to paste snippets from your clipboard directly into the editor and does not force you to search and open a file before. Although it works perfectly with huge files of several Gigabytes (or even Petabytes if you trust their own words) working with the clipboard is really handy. Beyond this it allows you to convert byte ranges to different integer formats and the find/replace actions concentrate on binary data as well.

Give it a try when you have to analyze binary data or your next strange text file the next time.

obj2opengl: convert obj 3D models to arrays compatible with iPhone OpenGL ES

Heiko Behrens — Thu, 27 Aug 2009 19:07:32 +0000

Whenever you want to use 3D objects modeled with a software such as Blender, 3ds Max or Cinema 4D in your iPhone Application or any other OpenGL project, you somehow have to make the designed data accessible to you program. To do this you can either load and interpret the files your models are saved into or you could directly provide the needed in-memory representation your program expects.

OBJ2OPENGL does the latter and acts as a converter from model files to C/C++ headers that describe vertices of the faces, normals and texture coordinates as simple arrays of floats.

Texturized and lighted 3D model with 8,056 faces on the iPhone

OBJ2OPENGL is a Perl script that reads a Wavefront OBJ file describing a 3D object and writes a C/C++ include file describing the object in a form suitable for use with OpenGL ES. It is compatible with Objective C and the libraries of the iPhone SDK.

The original idea and code base of this script comes from Margaret Geroch who kindly allowed me to enhance and republish this version. It now supports texture mapping and stored normals (instead of recalculating them). I have changed the structure of the generated arrays to work with glDrawArrays instead of glDrawElements. This is particularly needed for normals and textures where a vertex holds different information for some shapes. Also, this version includes several command line options to better control its behavior (such as scaling and moving the origin or setting the object’s and output file’s name).

If you can go with the defaults the conversion is as simple as

./obj2opengl.pl banana.obj

To include the converted object all you have to do is

// include generated arrays
#import "banana.h"

// set input data to arrays
glVertexPointer(3, GL_FLOAT, 0, bananaVerts);
glNormalPointer(GL_FLOAT, 0, bananaNormals);
glTexCoordPointer(2, GL_FLOAT, 0, bananaTexCoords);

// draw data
glDrawArrays(GL_TRIANGLES, 0, bananaNumVerts);

Examples

These are two models and generated sample output that is included in the provided archive:

Input	Output	Texture	Vertices	Faces
cube.obj	cube.h		8	6
banana.obj	banana.h	banana.jpg	4,032	8,056

Downloads

OBJ2OPENGL.ZIP (script and examples)
OBJ2OPENGL.PL

Please use the comment function of this post to discuss any problems or noteworthy results accomplished with help of this script. I will read feature requests, too. Feedback is highly appreciated.

Xtext in print

Heiko Behrens — Thu, 23 Jul 2009 10:06:08 +0000

Complementary to the extensive twitter presence, heaps of blog posts, the website relaunch as well as the successful webinar Xtext now enters print media. Today, the German iX Magazin for professional IT (issue 08/2009) publishes an article where I try to offer a general idea of Xtext: “Domänenspezifische Sprachen mit dem Eclipse-Projekt Xtext“.

iX Magazin issue 08/2009 prints my article about Xtext

But this is not the only publication that discusses Xtext: Next week the German Eclipse Magazin (issue 5.2009) will start a series by Jan Köhnlein and Sebastian Zarnekow that explains the technology in detail. And Sven Efftinge sums up the recent events around the Eclipse Modeling Project (including Xtext) in the very same issue (online version of this article already available).

Lars Corneliussen and Markus Völter started a series about DSLs in the in dotnetpro (so far, issue 05/2009 and 07/2009). Even though the focus is on .net platform the former version of Xtext (oAW 4.3) plays a significant role.

Unfortunately, all these publications are in German. If you are interested in writing an English article and need someone to review your work or if you have strong connections to English publishers who might be interested in an article written by us, please contact us via xtext at itemis dot com or comment this blog post.

That said, I want to thank the reviewers of my iX article for their valuable feedback!

Xtext: Model Prize Laureate

Heiko Behrens — Mon, 13 Jul 2009 23:34:17 +0000

What do a G1 Android mobile phone, a ticket for the Eclipse Summit Europe 2009, signed books about modeling as well as Xtext T-Shirts have in common? I am proud to say that itemis, the company I am working for, offers these juicy prizes to the winners of the upcoming Xtext contest.

If you are looking for a challenge and wanted to play around with Xtext since you heard about it this one is definitely for you. Pimp Xtext the way you want, combine it with colors, graphical aspects or any other technology, work with huge models, come up with a new programming language – your mind is the limit.

Be creative, use unusual techniques, explore your skills, do whatever it takes – we want you to get really excited about it so we will be excited as well.

You will have two months to submit an inspiring solution based on Xtext. And, with a bit of luck, you will not only win an Xtext T-shirt but program your next Java project for an Android mobile phone or meet other Eclipse enthusiasts at the Summit in Ludwigsburg.

Feel free to comment if you have any questions. Good luck!

Announcing the Xtext Webinar on Wednesday, 15th July

Heiko Behrens — Sun, 12 Jul 2009 14:30:10 +0000

Next Wednesday, Sven and I will hold the Eclipse Webinar “Xtext: Developing Domain Specific Languages”. We are going to classify Xtext compared to other concepts and frameworks and demonstrate its capabilities with a refined version of an example I presented in London last week. After that we discuss the versatile possibilities for extending and customizing the framework and finish with an exciting outlook.

The webinar will start at 5:00 pm GMT (convert to local time) and will take approximately one hour. We will offer a chat to answer your questions either live or in the end of the show. And since the program is not yet completely settled, it’s your chance to declare anything as a must-see. Just leave your comments here.

Update

The webinar was a great success! With the help of Sebastian and Moritz we were able to inform and entertain 130 Attendees. You can watch the replay at any time and follow some useful links either via its website or directly here:

Also, here you will find the final poll results. Thank you for you help, Lynn!

Do you have any experience with modeling? (99 Answers)

What do you think about Xtext? (59 Answers)

How Dropbox simplifies life

Heiko Behrens — Wed, 08 Jul 2009 12:15:33 +0000

Recently, I had to prepare a conference talk together with a colleague while both of us were working at different locations across the country. Via chats and phone calls we elaborated the topics, shared ideas and presented our current progress to each other. To share diagrams, images and the current version of the slides, well basically every digital asset, we were using Dropbox.

Dropbox offers a shared directory directly inside your file system you can then access from different computers simultaneously. It does so by synchronizing with a secure web storage in the background. It integrates tightly into your desktop and works on both Windows and Mac OS (and Linux but I cannot tell you about this). It notifies you whenever a shared file has been modified on another computer and a little icon overlay indicates whether a file is currently being synchronized. Technically, you could compare this to a classic version control system and indeed it comes with a history, too. But its seamless and hassle-free integration allows you to forget about all these details and to work with your image editor or word processor as you are used to, hit save and tell your buddy on the phone to open the file. It’s that easy.

I am using Dropbox for my personal life, too. You can control whether a folder is shared among others or is for private use only (default). I share my dropbox folder accross different Macs and PCs I am working on. When working on a laptop and a desktop at the very same desk sharing files between them is a common task for me. Before, the fastest way to transfer a file between these computers was copying it to a USB Stick, ejecting (and waiting for delayed write) it and mounting it at the other computer again. Funnily enough, sending an email with an attachment is sometimes even simpler than this procedure.

But with Dropbox I save the file into my Dropbox folder or even use this folder as primary editing location for my work. After hopping to the other computer this file in the latest version is already there without leaving any application on the first computer or performing additional tasks.

Dropbox is yet another tool that simplifies your daily life.

Xtext at DemoCamp London in June 2009

Heiko Behrens — Wed, 01 Jul 2009 13:44:11 +0000

This Monday the Eclipse DemoCamp took place in London at Skills Matter. You will find a comprehensive review at InfoQ by Alex Blewitt where you can read about NatTable (Dan Pollitt) and JQantLib/OSGi (Richard Gomes) as well as Xtext. And thanks to Eren Aykin you will find a video podcast of the latter, too!

This time I tried to spread the idea of DSLs with chess and different ways of expressing moves within the game. In the first part of my presentation I processed cryptic notations like “Rd2-c2″ or more natural equivalents such as “rook at d2 moves to c2″ to work with them as true Java objects and eventually visualized chess fields. Second, I tried to emphasize the value of DSLs in today’s software projects where we implemented another DSL live at the DemoCamp in the end. You will find my slides at SlideShare again.

It was quite informative to chat with the Eclipse folks in London afterwards. Most of them have a pragmatic view at modeling and tools in general. I really appreciate this! Thank you, Neil, for organizing this event and inviting via twitter.

Source Code

Loading chess DSL text files as Java objects:

package org.xtext.example.chess;

import org.eclipse.emf.common.util.URI;
import org.eclipse.emf.ecore.resource.Resource;
import org.eclipse.emf.ecore.resource.ResourceSet;
import org.eclipse.xtext.resource.XtextResourceSet;
import org.xtext.example.ChessStandaloneSetup;

public class JavaTest {

	public static void main(String[] args) {
		String filename = "some/path/MyModel.chess";
		Game g = getGame(filename);
		System.out.println(g.getWhitePlayer() + " vs. " + g.getBlackPlayer());
		for (Move m : g.getMoves())
			System.out.println(m.getSource() + " to " + m.getDest());
	}

	private static Game getGame(String filename) {
		ChessStandaloneSetup.doSetup();
		ResourceSet rs = new XtextResourceSet();
		Resource res = rs.getResource(URI.createFileURI(filename), true);
		return (Game) res.getContents().get(0);
	}

}

Impressions of Code Generation 2009

Heiko Behrens — Wed, 17 Jun 2009 22:43:59 +0000

On Monday, Sven, Sebastian, Moritz, Jan and me traveled to Cambridge where the Code Generation Conference takes place each year. Arriving one day ahead we had enough time to acclimate with fish ‘n chips and some ale at the local pubs before polishing our presentations.

The first conference day on Tuesday…

…started with a smooth introduction on modeling, DSLs and all the other terms specific to our focal point. It’s always interesting to see how other experts try to explain what we are doing and Juha-Pekka Tolvanen (MetaCase) did a great job even though he nearly ignored alternatives to graphical models.

Second, Sven and Sebastian talked about challenges in textual DSL design and concentrated on topics such as reusing languages and using models beyond the description of structures. If you follow their blogs you will certainly find out what they are interested in. This was the second time I noticed that the audience here at #CG2009 acts a bit more open-minded towards UML models and my coworkers sometimes had to play hardball with questioners.

Karsten and me skipped the next time slot to prepare ourselves for our own talk “Mastering Differentiated MDSD Requirements at Deutsche Boerse AG” we gave at the end of the day. We packed a lot material into 75 minutes but still managed to come up with a short demo that shows how Xtext can interact with graphical models. You can download the slides at slideshare but the demo is not yet ready, sorry (the attendees asked for this, please drop me a mail or comment on this post so I can inform you later on).

Punting in Cambridge (Foto by Karsten Thoms)

After a stressful day, the organized punting trip along the Cam made this day perfect to me.

Wednesday…

…was a completely different story to me. Instead of listening to or presenting well-known ideas I had the opportunity to get some deep insights of concepts I only read about before. After an amusing staged fight between Markus Völter (textual modeling) and Steven Kelly (graphical modeling) my day started with the well-prepared hands-on session about MetaEdit+ Juha-Pekka Tolvanen, Risto Pohjonen and Steven Kelly gave. From what I have seen I would say that this software is the most sophisticated graphical modeling tool at the market today.

The session I have joined afterwards was not that impressive but I compensated for this with today’s highlight: Language Definition, Extension and Composition with MPS. Markus Völter and Konstantin Solomatov complemented one another and impressed the audience deeply with the upcoming version of MPS. This was the first time I have seen a live presentation on this little pearl of modeling.

Some lightning sessions about Fit4oaw, MBase, UMLCanvas and GWT made the end of the technical part. A nice dinner with french impressions made the night a big success again.

I want to thank Mark Dalgarno and Andy Moorly for organizing this event. Questions about the room plan, the need for a different stage setup, giving up their seat at the dinner or ad hoc money exchange for thirsty attendees – no problems for them. Your upfront organization as well as your courteous appearance is simply overwhelming!

Update: This post has been published at The Model Driven Software Network, too.

iWannaSleep

Heiko Behrens — Tue, 09 Jun 2009 21:04:24 +0000

I love to listen to radio plays when going to bed and often I fall asleep only a few minutes after starting an episode. This works great for me but who switches off my Computer? A few years ago I have written a PC program that shuts down Windows after a given time. However, on the Mac there’s an even better tool: iWannaSleep.

iWannaSleep puts your Mac to bed

Marco Binder has written this little helper that puts your Mac to bed. It acts as a timer, fades out the sound and performs an action. This could be “shut down”, “stop iTunes” or “run apple script”. I usually stay with “put to sleep” (so my Mac has no hangover the next morning). The tool remembers the options I have chosen the last time and has never dozed off itself before doing its job.

New Xtext Logo

Heiko Behrens — Sun, 07 Jun 2009 21:49:23 +0000

Reading tweets, newsgroup posts, blogs, articles or press releases I am very excited to notice that xText gains increasing attention. As far as I can see most newcomers learn about xtext as a great tool to create domain specific languages (DSLs). Also, X-Text seems to fulfill a need many software engineers feel: Inventing their own programming language.

People are just starting to explore the possibilities and sometimes it is difficult for them to find the right word to name a concept or share an idea. We do our best to support those seekers and are glad to do away with a common uncertainness: The right spelling is “Xtext” and from today its logo does reflect this.

The new Xtext logo starts with a capital X

Beside every other wrong spelling “xtext” was the most prominent. It took us a while to find out why this was the case. Eventually, we realized that the omnipresent logo started with a lower-case “x” (convince yourself). So it was our own fault!

With the help of Carsten Oltmann we are proud to present the new version of the Xtext logo. Feel free to place it into your presentations, on your blogs or as a sticker at your laptop.

Downloads

I will provide the logo in four different flavours and in two different formats. You can download a vector graphic and a PNG in suitable sizes. The background color of the thumbnails are for reference only, the provided graphics are transparent.


EPS (vector)	EPS (vector)	EPS (vector)	EPS (vector)
PNG (800px)	PNG (800px)	PNG (800px)	PNG (800px)
PNG (300px)	PNG (300px)	PNG (300px)	PNG (300px)
PNG (100px)	PNG (100px)	PNG (100px)	PNG (100px)

Xtext at Eclipse DemoCamp May 2009 in Hamburg

Heiko Behrens — Tue, 26 May 2009 22:15:26 +0000

Yesterday’s Eclipse DemoCamp in Hamburg was a successful social event. The organizers Peter and Martin scheduled the Eclipse Stammtisch directly after the demo sessions so that many known but (to me) even more unknown faces gathered together to discuss the impressions at the bar.

Beside the talks from Moritz Eysholdt (Patching Models and Evolving Meta Models), Simon Zambrovski (Playing with Eclipse Common Navigator Framework) and Markus Alexander Kuppe (Distributed OSGi, RFC 119 – The ECF way) there was a talk about ObjectTeams again. Marco Mosconi demonstrated how one can weave manually written code into generated GMF editors with an aspect-oriented approach. Nice!

Me talking about Xtext at the Eclipse DemoCamp in Hamburg

I had the opportunity to talk about Xtext in front of an audience that mostly had not seen it before. Playing with expectations and trying out some new ideas was great fun. Xtext becomes more stable and doing live presentations is no risk but a pleasure.

For those who do not want to miss the pizza recipe nor the class schedule DSL, you will find attached the slides. Peter’s photos and Simon’s album give a visual impression of the event. Also, please note that we have just published ready-to-use distributions with the current Xtext RC2 release. Nothing should stop you from implementing your very own grammar. And if you come up with a textual DSL to avoid wrong IDs in your plugin.xml, let me know

Downloads

Mac SVN Server

Heiko Behrens — Sun, 24 May 2009 18:40:32 +0000

Last Wednesday Peter, Jan and me discussed the idea to blog about nifty little tools that make up our daily life with our Macs. With this post I will start to do so and want to present MAS, the Mac SVN Server, to you.

Whenever you have to prepare a digital show case, a presentation or simply try out a new programming library, the burnt IT-professional sticks to version control. And since the Internet is not yet omnipresent in trains, planes, secured environments or due to unpredictable events there is the demand for a locally installed system.

I am using Eclipse most of the development time so the choices are limited. And since I prefer SVN over CVS I was looking for a subversion server that can be used the Mac-ish way. Uli Kusterer put together an Apache server with the desired SVN capabilities built-in, tied it as a drop-installable application and called it MAS. It comes with a simple GUI that allows you to manage users to grant access to the repository that resides in your home directory (~/Library/Application Support/MAS). Download and drop it into you application directory. There’s nothing more to say.

For the last months MAS has done exactly what it was designed for. It supports me every time I want to put something under version control and stops serving when closing the application.

And tomorrow’s presentation at the Eclipse DemoCamp in Hamburg will benefit from it, too!

Generation Gap Pattern

Heiko Behrens — Thu, 23 Apr 2009 19:35:51 +0000

The Generation Gap Pattern is a common way to weave manually written code into generated software artifacts. While this pattern describes how to structure your classes logically it does not teach you where to place these classes physically as files into the filesystem.

Figure 1: The Generation Gap Pattern

Separating generated files from manually written code is best practice for many reasons. It enables you to use version control wisely and makes the distinction between generated and manually written code easy. The Eclipse EMF Modeling Workflow Engine together with M2T Xpand allows you to accomplish this goal in different ways.

In this post, I will present three different approaches that share some common ideas. Each strategy uses a dedicated directory for generated class files whereas manually written subclasses are stored for themselves in a different directory.

General Directory Layout

Both sets of classes belong to the same package but reside in different source folders. Framework classes should be kept in yet another directory and might be placed in a package specific for the framework as seen in Figure 2.

Figure 2: Schematic directory layout of an Eclipse Java project

In Eclipse you can configure such a project structure by adding new source folders (New → Source Folder…) or by declaring ordinary folders as source folders in the project properties (Properties → Java Build Path → Source).

Please note that folder names such as src-generatedClasses are meant to be schematically and stand for a category of folders each. In real world projects you might have several source folders that contain generated artifacts and you might deal with many folders or even projects that contain manually written classes. In the following sections you will see how these categories of folders can be used in practice.

Generate Once

Peter describes a directory layout many Xtext users are familiar with. Generated artifacts go into a folder src-gen whereas manually written classes will be stored in a folder src-once. Each time you run the generator the content of folder src-gen will be purged and generated again whereas the the content of src-once will remain untouched.

Figure 3: Generate Once collects one-time generated artifacts for future editing

Since each model element A leads to two classes AbstractA and ConcreteA (Generation Gap Pattern) you can reduce the amount of manual work by generating the class ConcreteA if it does not exist, yet. During the next run of the generator the class ConcreteA won’t be generated again, hence the name “once”.

Configure an additional outlet in your EMF MWE file:

Using M2T Expand you can than refer to the outlet MANUAL where appropriate

«DEFINE ConcreteClass FOR Element»
   «FILE this.fileName() MANUAL»
   ...
«ENDDEFINE»

This approach works well in many scenarios but has its limits. As seen in Figure 3 problems arise whenever you delete or rename a model element. In these cases each concrete artifact at src-once that does not correspond to a model element anymore is abandoned and will remain with compile errors. This is desired for classes that hold manual code but is cumbersome for those that do not.

Figure 4: Generate Once in package explorer

For scenarios where a huge amount of generated classes is customized only in a few cases the “Generate Once” approach leads to unwanted manual refactoring effort including file movement. Life is getting worse when you are working with a complex folder structure instead of a single flat directory. Figure 4 might give you an idea of how things will look for growing models.

Conditional Generation 1 (with one gen-folder)

The following approach plays well when only a small subset of classes has to be extended with manual code. According to the Generation Gap Pattern for each model element A there is a generated class AbstractA as well as an concrete class ConcreteA. But in contrast to the “Generate Once” approach both files will be placed in the very same folder src-gen and therefore deleted and regenerated for each generator run.
There is one exception to this behavior. Whenever the generator finds a file ConcreteA in the folder src-man it skips the generation process for this particular file. This is how you introduce manual code.

Figure 5: Conditional Generation 1 reduces manual refactoring effort

At first glance this approach seems to be similar to the solution above. But when deleting or moving model elements this approach really pays off. Each concrete class that does not contain manual code will be deleted and regenerated. Therefore, when moving or deleting the model elements no additional manual work has to be done. Also, a quick look at src-man reveals any code that has been written manually.

Figure 6: Conditional Generation 1 in package explorer

To implement the desired behavior of the generator users of MWE can configure an outlet with a special veto strategy. Please note that the outlet MANUAL does not need to keep files (overwrite=”true”), they will be purged by the directory cleaner anyway.

Such a veto strategy would read like:

public class CondGenVetoStrategy implements VetoStrategy, VetoStrategy2 {

	private String path;

	public void setPath(String value) {
		path = value;
	}

	public String getPath() {
		return path;
	}

	public boolean hasVeto(FileHandle fileHandle) {
		URI fileToBeGenerated = fileHandle.getTargetFile().toURI();
		URI pathToGenerateInto = new File(fileHandle.getOutlet().getPath()).getAbsoluteFile().toURI();
		URI relativeFileName = pathToGenerateInto.relativize(fileToBeGenerated);
		File potentiallyExistingFile = new File(this.getPath(), relativeFileName.toString());

		return potentiallyExistingFile.exists();
	}

	public boolean hasVetoBeforeOpen(FileHandle handle) {
		return hasVeto(handle);
	}
}

oAW 4.x: VetoStrategy2 has been introduced with oAW 4.3.1.

Unfortunately, the advantages of this approach do not come for free: Compared to “Generate Once” it is more difficult to introduce manual code since it is harder to understand the needed steps. One has to create a concrete class in the src-man folder manually (or move it from src-gen and remove all comments that mark them as generated) where no class exists, yet. This might seem to be a no-brainer but can lead into trouble when defining a process for large projects. This is especially true for the unlikely case that you check-in generated code of src-gen.

Conditional Generation 2 (with two gen-folders)

A slighty different way that basically follows the same idea introduces yet another folder src-gencond.

Figure 7: Conditional Genration 2 lists classes that can implemented manually

As you can see in Figure 7 the generated artifacts are split into the folder src-gen where the abstract classes reside and the newly introduced folder src-gencond. The latter contains only the concrete classes that could be replaced by manually implemented classes. In contrast to the “Conditional Generation 1” approach the users are now able to find classes that can be augmented be manual implementations without any challenge. Users still have to move classes from src-gencond to src-man by hand but it is simpler to communicate the necessary steps.

Figure 8: Conditional Generation 2 in package explorer

As you can see in Figure 8 one can easily identify that there are two classes that could be implemented by hand. Such a folder structure can pay off when different groups of developers are dealing with a fairly large and scattered set of classes.

In order to realize “Conditional Generation 2″ you simply reconfigure the outlet MANUAL to write its output to src-gencond. Also, a second directory cleaner removes all files from this directory before code generation starts.

Comparison

Each of these solutions do their job in real world MDSD projects. Where projects with rather stable interfaces go with the “Generate Once” approach larger projects address growing maintenance effort with the “Conditional Generatation 1/2” solution. The move from “Conditional Generatation 1” towards “Conditional Generatation 2” is rather trival and can smoothly be taken within a running project.

I’d be happy to read about your experience with these or different project setups.

Xtext Workshop

Heiko Behrens — Tue, 14 Apr 2009 17:21:13 +0000

Sebastian and me had the opportunity to give some exciting Xtext Workshops during the last two weeks. Starting with internal trainings at different offices of itemis we continued our tour to our customers. In groups from 4 up to 12+ attendees we explained simple things as well as more complex topics such as Scoping or Actions.

By now I won’t call us Xtext experts but one thing is safe to say: Beyond the convincing basic functions Xtext does an awesome job when facing advanced topics.
(Falko Riemenschneider)

I am glad to see that TMF Xtext got rid of many strange issues oAW Xtext had when it comes to corner cases. And the extensibility with Google Guice will be of great value.
(Steffen Stundzig)

Please understand that I can neither publish the slides nor exercises of this workshop since it is material our customers pay for. We are still working on more content that will be publicly available. Meanwhile, if you are interested in Xtext the newsgroup is a valuable place to share experience and to delve into questions the documentation cannot answer.

For you itemis co-workers, read on at the intranet and download the material.

Google App Engine for Java and Google plug-in for Eclipse

Heiko Behrens — Wed, 08 Apr 2009 08:43:27 +0000

Today, Google announced that the Google App Engine will support Java. This is great news for every Java developer who wants to experiment with the cloud. At the moment Google grants an “early look” to only a few (10,000) developers that sign up early. Everybody else can code, test, debug und run Java-based applications using the SDK locally but won’t be able to upload the application until this service is available for everybody.

At the same time the Google Plug-in for Eclipse has been announced, too. Together with the 1.6 release of GWT there’s much to explore and a long and eagerly awaited feature comes true.

This is by far better than the fake of a Google App Engine for Fortran.

Xtext at EclipseCon 2009

Heiko Behrens — Thu, 02 Apr 2009 13:28:51 +0000

This year’s EclipseCon in Santa Clara was not only about Eclipse itself. For me, a silent observer who noticed this event only via the web, it acts like an important hub for many ideas and achievements inside and around the Eclipse ecosystem in general. One of these little treasures that have been mentioned is Xtext. What else could have been expected?

Sven and Jan had a talk about the upcoming release of TMF Xtext and shared their slides afterwards. During the event one could recognize some nice comments about Xtext at twitter.

But for me, the most interesting digital find is an interview with Wolfgang Neuhaus I stumbled across at Ian’s Blog. Without the demand for in-depth knowledge of specific tools Wolfgang introduces the ideas behind Xtext in a brief and precise way.

Xtext M6 with more documentation and stable API

Heiko Behrens — Thu, 19 Mar 2009 09:53:03 +0000

According to the project plan we have published the sixth milestone version of TMF Xtext this Tuesday. Please note, this is not a release candidate, yet. Nevertheless, it’s another huge step towards the Galileo release in June and tough guys may want to explore M6 as some early adopters already do.

We know about bugs and missing features but with good cause I want to draw your attention to this release. Apart from the constantly improved core documentation we are beginning with documents like “Getting Started” or ”Migration from oAW Xtext“. The latter is far from being finished and will summarize the lessons we have learned together with our customers that have be been using TMF Xtext since M5 and earlier.

Xtext users might be glad to hear that the API of Xtext is reliable. To accomplish this goal we leverage the annotation @java.lang.Deprecated for parts of the API that won’t be supported in future. But more interesting is the newly introduced annotation @org.eclipse.xtext.Stable. An interface tagged this way is not truly stable itself since we might introduce new methods in future but the annotation might help you anyway. It directs you to an abstract class that you should derive from. Whenever a new method will be introduced in future this class will complement your work with a null implementation your can override as necessary (does anyone know how this pattern is called?).

Interface with @stable and corresponding abstract class

So, even if you won’t try out TMF Xtext at this stage this documentation material might give you a preview of what you can expect in June. Check out the New and Noteworthy Page for a general overview of this release.

Feedback is welcome through the news group and bugzillas.

100 Liegestütze in 6 Wochen

Heiko Behrens — Wed, 18 Mar 2009 09:36:04 +0000

Nachdem ich dieses Unterfangen im Spätsommer aus unterschiedlichen Gründen leider abgebrochen hatte, werde ich dieses Mal mit zwei Mitstreitern erneut versuchen, die magische Grenze zu durchbrechen. Wie? Steve Speirs hat im Juni 2008 ein Trainingsprogramm veröffentlicht, mit dessen Hilfe auch Ungeübte innerhalb von sechs Wochen in die Lage versetzt werden, 100 (in Worten: einhundert) Liegestütze am Stück durchzuführen.

Die abgeschlossene Hallen-Volleyball-Saison 2008/2009 sowie die berufsbedingte Einschränkung des Mannschaftstrainings berauben mich der wirkungsvollsten… Begründung eines weiteren Aufschiebens. Dazu gibt es mit der passenden iPhone-Anwendung und der persönlichen Trainingswebseite auch genug technisches Spielzeug, um die Motivation aufrecht zu erhalten. Ich werde über den Fortgang berichten.

Xtext and oAW at Code Generation 2009

Heiko Behrens — Fri, 06 Mar 2009 18:19:46 +0000

The conference program of the Code Generation 2009 has just been released and there will be several sessions that directly or indirectly address Xtext and openArchitectureWare.

Tutorial (75 minutes, Tuesday morning)
Challenges in DSL Design
Sven Efftinge, Sebastian Zarnekow
Case study (75 minutes, Tuesday afternoon)
Mastering differentiated MDSD requirements at Deutsche Boerse AG
Heiko Behrens, Karsten Thoms
Hands-On (180 minutes, Thursday midday)
Xtext Workshop
~~Heiko Behrens~~ Jan Köhnlein, Moritz Eysholdt, Sebastian Zarnekow

Apart from those, there’s a think tank that might strive oAW, too. Interested in Microsoft’s and JetBrains’ accompanists I am looking forward to the “Introduction to the Microsoft Oslo Modeling Platform” as well as “Language Definition, Extension and Composition with MPS”.

Finanzkrise anschaulich erklärt

Heiko Behrens — Wed, 04 Mar 2009 00:10:11 +0000

Jonathan Jarvis zeigt als Teil seiner Abschlussarbeit in einem Animationsfilm, wie es zur anhaltenen Finanzkrise kam (gelesen bei baekdal). Mich fasziniert neben der ikonisierten Bildsprache vor allem die plastische Darstellung des im Studium so häufig erwähnten Leverage-Effekts.

Inhaltlich etwas vollständiger aber weniger spektakulär, ein Aufklärungsvideo vom BMF. Während Jonathan nach einer kurzen Einführung und dem weiß aufleuchtendem Wendepunkt ein (auch farblich) pessimistisches Ende skizziert, geht es bei der simpleshow schon etwas freundlicher zu: Wer in Deutschland lebt und besonnen handelt hätte nichts zu befürchten. Einfach das liebe Geld in Staatsanleihen investieren und abwarten.

Leider erwecken die beiden Kurzfilme den Eindruck, dass die Finanzkrise nur Immobilienbesitzer oder Menschen mit größeren Spareinlagen betrifft. Die Übersicht der Tagesschau klärt in dieser Hinsicht auf. Für den besorgten Arbeitnehmer fasst der Focus allgemeine Ratschläge zusammen. Mein persönlicher Favorit gleich zu Beginn der Liste:

Halten Sie sich zurück mit apokalyptischen Prognosen. Das Unternehmen will und braucht Optimisten.

Klaro! Wikipedia bietet für den interessierten Leser mit dem Artikel “Finanzkrise ab 2007” dazu einen guten Startpunkt für weitere Recherchen. Bleibt zu hoffen, dass dieser Titel bald um eine weitere Jahreszahl zur Eingrenzung des Zeitraums ergänzt wird.

itemis unter den Top 10 Arbeitgebern im deutschen Mittelstand

Heiko Behrens — Tue, 17 Feb 2009 14:59:54 +0000

Ende Januar hieß es in einer internen E-Mail an meine Kollegen und mich aus Richtung des Marketings:

Morgen haben wir die Presse (Bild und WDR) im Haus. Keine Angst. Es gibt jetzt keine bestimmten Regeln oder so. Wir sind Perfekt.

Diese Formulierung zauberte schon ein Grinsen in mein Gesicht und ich konnte mich nicht zurückhalten, in meinem Bekanntenkreis davon zu berichten. Inzwischen haben sich die Nachfragen gehäuft, wo genau in der Bild denn nun was zu lesen war. Ich selbst besitze keine Ausgabe dieses Blatts und leider ist es der itemis nicht gestattet worden, ein eingescanntes Exemplar zu verlinken. Ein kleiner Trost: Es gibt in der Mediathek vom WDR den Mitschnitt aus der Lokalzeit zu sehen.

In unserem Unternehmensblog verbirgt sich hinter der Überschrift “Top-Arbeitgeber 2009″ noch einiges zu den Hintergründen, die im Fernsehen nur knapp dargestellt und in der Bild dem Format angemessen ausgelassen wurden. In diesem Zusammenhang ist sicher auch die jüngst erhaltene Auszeichnung “Great Place to Work®” von Interesse.

Downloads

Speed Comparison of oAW and M2T Xpand

Heiko Behrens — Tue, 10 Feb 2009 20:53:04 +0000

Migrating a real world openArchitectureWare Xtext/Xpand project to the corresponding Eclipse M5 modeling projects (TMF, M2T) I had the opportunity to see the results of our ongoing speed improvement effort. While the part of code generation of this project originally took nearly half an hour we were able to reduce its execution time below 3 minutes with the help of a brand-new M2T profiler. After that I migrated the templates, checks and workflow(s) to the package structure of M2T and did some measurement.

This project generates about 1.500+ Java and C++ files as well as some X(HT)ML and plain text. It consists of 250+ Xtend functions and 200+ Xpand defines in more than 80 files. See below the runtime characteristics while generating the artefacts of the very same project using oAW 4.3.1, the Eclipse milestone M5 without and with the recently introduced polymorphic dispatch caching enabled:

Execution time (code generation only)

Looking just at these numbers, I would confidently say that the upcoming Eclipse M2T Xpand runs significantly faster than the good ol’ oAW Xpand!

Building a java classpath from a windows batch file

Heiko Behrens — Mon, 26 Jan 2009 18:03:17 +0000

A great feature introduced with the JDK 6 is the improved classpath syntax for including Jars of a specific directory. This allows you to do this

javac -cp "lib\*" MyClass.java
java -cp "lib\*" MyClass

from the command line without using a build system like Maven or Ant. But each of you who has to build and run Java classes with the JDK 5 or earlier and suffer from some project restrictions that reduces the set of tools to the ordinary command line will have to build the proper classpath by naming each Jar separately:

javac -cp "lib\jar1.jar;lib\jar2.jar" MyClass.java
java -cp "lib\jar1.jar;lib\jar2.jar" MyClass

On a Unix based system one could use glob in a shell script. The doomed Windows users can either use some shell replacements or have to build the command line with the arguable help of batch files. This blog post serves as a reference for those who stumble across loops and delayed expansion of variables in Windows batch files. To make the story of a bumpy road short here is the working solution for Windows XP:

REM needed to overcome weird loop behavior
REM in conjunction with variable expansion
SETLOCAL enabledelayedexpansion

REM construct classpath of seperate jars
cp=explicitlyKnownJar1.jar;explicitlyKnownJar2.jar;

FOR %%F IN (lib/*.jar) DO (
  SET cp=!cp!;lib/%%F%
)

javac -cp "%cp%" MyClass.java
java -cp "%cp%" MyClass

Please note that you should select the needed Jars carefully since Windows XP cannot handle environment variables longer than 8KB. Try to use relative files names to “solve” this issue. If relative paths are no option you could try to use virtual drive letters instead.

Anyway, my advice is: Convince your “build manager” that you need a true build system in order to ensure the product quality and safe hours of work (around) time. In Eclipse a first draft of such an Ant script could be produced using “Export… Ant Buildfiles”.

Twitter und Facebook für Politik und Produkte

Heiko Behrens — Sun, 18 Jan 2009 23:01:50 +0000

Längst gewinnen Sportvereine neue Mitglieder über ihre Präsenz im Internet. Der Einzelhandel versendet E-Mails beim Eintreffen neuer Ware und die Status SMS beim Logistiker ist keine Besonderheit mehr. Die Zeiten ändern sich! Das hat vor einigen Wochen auch der amerikanische Wähler erfahren können, als gebündelte Online-Kampagnen zu Micropayment aufriefen oder ein ausgeklügeltes Logodesign auf dem Rücken viralen Marketings zu selten erreichter Sichtbarkeit führte. Und doch gibt es noch immer Kampagnen, die sich das Medium Internet nicht zunutze machen.

Thomas Baekdal zeigte heute an einem “ungöttlichen Beispiel“, wie selbst zeitgemäß ausgerichtete Kampagnen viel Potenzial verspielen. Dabei geht er nicht nur auf offenkundige Schwächen ein, er postuliert ebenfalls, worauf es beim Online-Marketing ankommt: Raum für (scheinbare) Individualität. Erwähnenswert ist mit Sicherheit auch die Gegenüberstellung unterschiedlicher Formate wie Facebook-Seiten und Blogs, die er nur wenige Stunden später aufgestellt hat. So ließen sich heute mit nur einer einzigen Facebook-Seite über 13.000 bekennende Anhänger einer Idee gewinnen, noch ehe ein Blogeintrag verfasst sei. Letzterer hingegen wäre deutlich nachhaltiger.

Ich bin mir sicher, dass die kommenden Jahre viel Veränderung im Bereich der Kommunikation mit dem Bürger, dem Konsumenten und dem Individuum bringen. Und wo der klassische Betriebswirt früher in Größen von Printauflagen gerechnet hatte, könnte es zukünftig in Vorlesungen 2×2-Matrizen zum Lebenszyklus von Onlineformaten geben.

Denn wer hätte vor zwei Jahren gedacht, dass klassische, deutsche Medien über den aktuellen Stand einer Landtagswahl twittern?

Videos vom World Usability Day 2008 in Hamburg

Heiko Behrens — Thu, 08 Jan 2009 18:23:37 +0000

Durch einen Gruppeneintrag von Matthias bin ich auf die Videos vom Hamburger World Usability Day aufmerksam geworden. Die Mitschnitte zeigen zwar nur einen Teil der gehaltenen Vorträge, vermitteln aber einen Eindruck, worum des den norddeutschen Usability Professionals heute geht: “Wie bekommt man das Maß der Usability in der Praxis eingefangen”. Aber auch die anderen Erfahrungsberichte sind recht aufschlussreich.

Unser Versuch, im Kieler Raum eine Veranstaltung zu realisieren, ist 2008 aus zeitgründen leider gescheitert. Thorsten Wilhem, ein Mitglied aus dieser Planungsrunde zeigte stattdessen in Hamburg, wie sich Usability-Testing in der frühen Projektphase behauptet.

Vielleicht klappt es in diesem Jahr endlich in Kiel…

Multiple Inheritance and the Least (Unambiguous) Common Compatible Type

Heiko Behrens — Mon, 08 Dec 2008 21:57:38 +0000

While working on Xtext and the inference of meta-models of a given grammar I encountered different problems that could be broken down to a well-known question: “What is the least common compatible type of those?”. While Liskov discusses how subtypes and supertypes could be derived in general I already had a hierarchy of defined types. Books like Types and Programming Languages seem to cover questions like this exhaustively and come to a quite simple view at this topic.

The following diagrams are geared to the UML notation. Boxes are types in this context whereas an arrow indicates a supertype relationship.

Figure 1

In Figure 1, A is the direct supertype of B where C is a direct and E an indirect subtype of A. Each type is compatible with A. Type E and F are compatible with B, which is also the least common super type of E and F. Every type is compatible to itself and the least common compatible type of D and G is D again.

So far, this is pretty obvious. The difficulties arise when dealing with Ecore, or EMF in the context of Eclipse. The meta-model of EMF says, that any EClass (read: Type) can have any number of supertypes. This leads into potential scenarios of multiple-inheritance where things are not so obvious anymore.

Figure 2

Figure 2 illustrates a simple scenario, where D and E have more than one supertype. Both, D and E are compatible with B and C. One can argue whether B or C should be called the common compatible type of D and E. It’s even harder to tell, whether B or C is the least common compatible type. Or are they both?

In the context of Xtext it was necessary to name a single type that works not only as an arbitrary compatible type in general (where both B and C would fit) but would unambiguously be the least common compatible type. In Figure 2 this would be A.

A more complex scenario can be seen in Figure 3. Different associates came up with different proposals each time I asked for, say, the Least Unambiguous Common Compatible Type (LUCCT) of D and F.

Figure 3

Some argued B is as “tight” as C. Others said, the absence of a unique root causes some sort of ambiguity. In the end we agreed that neither C nor B nor A would be “unambiguous enough” to fulfill the requirements of a so-called LUCCT. We also agreed that this question is more challenging than picking the most specific type that is compatible with F and D.

After thinking about this it turns out that a proper solution is not easy but it is no rocket science either.

First, find the intersection of all compatible types of the inspected types.
Next, concentrate on this set only and find all types that are directly or indirectly connected to every other type in the set. These are the LUCCT candidates.
Last, select the most specific candidate of step 2 as the result. If there are no candidates there’s no LUCCT for the inspected types. Yes, there is always a most specific candidate otherwise it would not be a candidate.

Figure 4

In the given scenario of Figure 4 where one wants to determine the LUCCT of G and I the set of compatible types consists of A, B, C, D, E and F. These types on their own are all directly or indirectly subtypes or supertypes of A and D whereas pairwise compared B and C or E and F are not. Since D is more specific than A the LUCCT of G and I is D, voilà!

The gentle reader may apologize the absence of terms like graph reduction or isthmus to explain this method.

Use Eclipse as diff tool

Heiko Behrens — Tue, 02 Dec 2008 18:39:05 +0000

Coming from the windows platform I am used to tools like WinMerge or AraxisMerge (commercial) that offer a more comfortable way to compare the content of files than diff --side-by-side. To my suprise I did not find a single useful external diff tool for Mac OS.

More or less accidentally while working with Eclipse and CVS and its function “Compare with latest from HEAD” I stumbled on a grayed menu item that says “…with each other”.

It turns out that Eclipse supports comparing arbitrary files two-way and even three-way. You simply have to select the files to compare and invoke the context menu. Those files only need to be in your workspace. It is not necessary to have them under revision control. Great!

Blog to your mom via email

Heiko Behrens — Mon, 24 Nov 2008 20:49:05 +0000

Many surfers on the web are not familiar with RSS feeds nor do they own an aggregator to collect news automatically. Those “old-fashioned internet citizens” gather information by opening websites one after the other and scanning their content by hand (or eyes and memorization, so to speak). While such a “bad habbit” might be sufficient for private users professional publishers gamble away regular readers by ignoring their affectations.

Reading a mail costs me only a minute but opening all these websites takes the whole day!

This is what my mom replied to me recently. She reads the web as many others do, searches at amazon or ebay and does emails, too. But subscribing to a feed is another story. This is where services like nourish come in.

Nourish acts as a publisher and sends out emails with the relevant news each time a feed indicates changes on a website. It’s much like a newsletter service with campains and managed subscribers where the content itself comes from an arbitrary RSS feed instead. This is a great way to reuse existing content and infrastructure while developing the reader base.

But thinking about my mom, I am looking forward to complaints of all this spam in her mailbox

Model-Based UIs and Refactorings at the ESE 2008

Heiko Behrens — Fri, 21 Nov 2008 10:41:18 +0000

Beside many other interesting presentations and talks there were two exciting projects I learned about at the Eclipse Summit Europe 2008.

Olivier demonstrates Wazaabi 2.0 to me

On Wednesday, Olivier Moïses, the lead of wazaabi, gave me a demonstration of his ideas about models and UIs. While the Eclipse E4 team at the E4 Symposium still had a strong argue whether modeling would be an advantage that justifies another layer on top of RCP Olivier already did it! Have a look at the preview of Wazaabi 2.0 and you will see how such a live model based on EMF could work.

Jeff gives a great presentation on Ludwig and refactorings with the LTK

Jeffrey Overbey overwhelmed me on different levels. First, his elegant presentation style and confident appearance towards the audience made the rather theoretic topic “refactoring” an entertaining joy (Read Peter’s Post about this). Second, Jeff concentrates on topics where Xtext will advance in the near future, too. On top of his own framework parser/AST generator Ludwig and the Eclipse LTK he will concentrate on refactorings of arbitrary languages. Third, he seems to be as friendly as all the other modeler guys are Hopefully, his work and Xtext will cross-fertilize.

Modeling Symposium at Eclipse Summit Europe 2008

Heiko Behrens — Tue, 18 Nov 2008 17:55:36 +0000

Today, the Eclipse Summit Europe 2008 starts with different symposia reaching from embedded runtimes over banking industry to test-driven development to name a few. At the Modeling Symposium Peter and me presented a position paper that outlines three possible ways of storing models while preserving their textual representation. Ed gives a summary with some photos, too.

During the day there were some great contributions including “COPE: Coupled Evolution of Metamodels and Models for EMF” from Markus Herrmannsdoerfer and a felicitous closing by Jos Warner. He discussed “Big Models – An Alternative Approach”. As it turned out in the Open Space Sessions afterwards, working with big models seems to be one of the current challenges in the modeling world.

Unfortunately, the presented papers cannot be downloaded from a central location but are beeing shared via email between the attendees. To make at least our contribution available to the public you can download the paper as well as the presentation slides right here.

Still, two more days full of interesting sessions to come.

Downloads

Zuginfo für das iPhone

Heiko Behrens — Fri, 24 Oct 2008 09:27:43 +0000

Eine meiner Lieblingsanwendungen aus dem Apple App Store ist Zuginfo von ifoi ware. Die Anwendung ist in der Lage, komfortabel Verbindungsanfragen an die deutsche Bahn zu stellen.

Toll an der Kombination ist, dass die Bahn nicht nur Zugverbindungen ausweist, sondern ebenfalls mit Bushaltestellen umgehen kann. Wenn sich also mein morgendlicher Zug nach Kiel mal wieder um einige Minuten verspätet hat, kann mir Zuginfo dabei helfen, eine der möglichen Buslinien Richtung itemis auszuwählen.

Für meine Fahrt nach Bremen heute Abend kann mir das iPhone daher genau sagen, wann ich an der nahegelegenen Bushaltestelle einsteigen muss, damit ich meinen ICE nach Bremen bekomme.

Toll ist auch die Funktion, Start und Ziel zu vertauschen. Wenn die Anwendung jetzt noch eine Liste der zuletzt besuchten Ziele verwalten könnte, wäre ich restlos zufrieden.

Im Blog von ifoi ware deutet sich bereits die kommende Version 1.1 von Zuginfo an, ich bin gespannt.

Migrate contacts from Sony Ericsson K750i to the iPhone

Heiko Behrens — Tue, 21 Oct 2008 07:03:48 +0000

Today, I wanted to migrate contacts from my good ol’ mobile to my new iPhone 3G. Since apple’s telephony product neither supports bluetooth nor allows importing via SIM card I decided to walk the old fashioned way: Data via cables.

The propietary software vom Sony Ericsson only works on my PC but the iPhone is connected to my iTunes on the Mac Book Pro on the other hand. Therefore, this procedure was a bit exhausting.

The setup:

95 contacts inside my Sony Ericsson K750i connected via USB (no Bluetooth at my PC) to the
Propirietary PC Software running at my PC (no Mac version available)
Using its sync mechanism to export the contacts to Microsoft Outlook (software does not provide file based export)
Exporting the contacts as vcards with the open source software Outport (Outlook 2003 itself does not offer this)
Moving nearly 100 Files from my PC to my Mac Book Pro with DropBox (far more comfortable than a USB stick for tasks like this)

And now the fun stuff:

Selecting these files in the Finder on the Mac and saying “open”. This merges the contacts into my addressbook and syncs them with the iPhone.

Rückfragen zum oAW Powerworkshop in Hamburg

Heiko Behrens — Tue, 14 Oct 2008 14:29:03 +0000

Bei der lockeren Atmosphäre gestern und heute bei einem von Jans Workshops zum Thema open Architecture Ware blieben einige Fragen an mich offen. Die Gespräche in den Pausen und bei Erfahrungsberichten ließen schließlich viele Möglichkeiten, Ideen auszutauschen, zu denen ich noch einige Quellen nachreichen wollte.

Automatische Whitebox-Tests für .net

Das Projekt Pex (Programm EXploration) soll den manuellen Aufwand bei der Gestaltung von Unit-Tests im .net-Umfeld signifikant verringern.

MDSD Today

Von morgen bis Freitag findet in Elmshorn die MDSD today 2008 an der Nordakademie statt. Auch über Xtext wird bei dieser Gelegenheit gesprochen. Peter und Sven erzählen uns, warum textuelle DSLs Freiheit bedeuten und Schmetterlinge im Bauch flattern lassen…

Dokumentation zu Ecore

Als Bestandteil des Eclipse EMF findet das (Meta-) Metamodell Ecore an vielen Orten Erwähnung. Leider bleibt es dabei häufig nur bei dessen Nennung. Neben pragmatischer Dokumentation auf den Seiten von Eclipse könnte die Arbeit “Vergleich von Metametamodellen” von Marcel Hoyer ein wenig Hintergrundwissen bieten.

Lexerregeln in Xtext

Möchte man eigene Lexerregeln in oAW Xtext erstellen, geht das über sogenannte Native rules. In der TMF Xtext-Version, an der wir derzeit arbeiten, funktioniert das mit den Lexer rules schon deutlich besser. Insbesondere in Kombination mit Return Types und eigenen Value Convertern gewinnt dieses Feature spürbar an Wert.

Xtext im Standalone-Editor

Gerade wenn das Tagesgeschäft nicht mit Eclipse realisiert wird, stellt sich die Frage, wie man in den Genuss des generierten Xtext-Editors kommen kann ohne auf Eclipse umsatteln zu müssen. Eine Antwort darauf bieten die Seiten zur Produkterstellung und zum -Export in der Hilfe von Eclipse. Schließlich handelt es sich bei dem Editor um ein einfaches Eclipse-Plug-in.

Working for itemis

Heiko Behrens — Thu, 02 Oct 2008 14:00:23 +0000

Two weeks ago I joined itemis AG, a company that offers consultancy and focuses on model-driven software development. Even though our main office is located in Lünen near Dortmund you will find me at our office in Kiel.

Sven, Peter, Jan, Mortiz, Dennis and me leverage and develop Java tools in the field of domain specific languages. If you ever read about Xtext, that’s us!

You can find my colleagues at conferences, read their articles or book their services as experts in software construction. The latter happened to my colleagues Holger and Torsten who are working at our “open source lab kiel”, too. They support a customer in Stuttgart and I haven’t seen them, yet.

And what am I supposed to do at itemis?

Well… being the freshman on board I am “swabbing the deck”! A whole bunch of new acronyms, exciting tasks and congenial colleagues come along this challenge. You can expect some illuminating posts in the near future on this blog.