[Pub] Eclipse Plugin for Mule and Mule Data Mapper

The main topic of the actual Eclipse Magazin is called Plugin Parade, where I published a short article about the new Mule IDE and Mule Data Integrator, two Plugins for Eclipse. The Mule IDE provides an integrated Mule server for Eclipse. Therefore the test of Mule environments in Eclipse is very comfortable and easy. As data transformation is a significant part in an ESB, a graphical support tool such as the Mule Data Integrator provides a powerful tool for integration developers. Mule Data Integrator is an end-to-end solution for complex data integration and transformation, simplifying the development, maintenance, and deployment of data maps. One of the major advantage of the data integrator is the integrated Test Suite.

The combination of the Mule IDE and Mule Data Integrator provides a really good environment for your integration development.

[Conf] Cloud Computing at OOP 2010

Today I attended the session called "Cloud Computing ohne Buzzwords - und wie sieht die Zukunft aus" at the OOP 2010, provided and overview of Cloud Computing and their effects to present Software Architectures. Till this day I had no experience with Cloud Computing, and this session gave me the opportunity to hear some basic information about Cloud Computing and the benefits and risks that such a paradigme comes with. Good canditates are Amazon or Google. Both provide a wide range of services around the topic Cloud Computing.

A very interesting point is that RDBMS do not work very well in  the Cloud and alternative systems such as "NoSQL" becomes more popular through Cloud Computing:

Next Generation Databases mostly address some of the points: being non-relational, distributed, open-source and horizontal scalable. The movement began early 2009 and is growing rapidly. Often more characteristics apply as: schema-free, replication support, easy API, eventually consistency, and more. So the misleading term "nosql" (the community now translates it with "not only sql") should be seen as an alias to something like the definition above [Source: http://nosql-database.org/]

From my point of view, new kind of software systems make use of new platforms, such as Facebook, LinkedIn, Twitter in order to persist their data. And these platforms use this new mechanism to persist data. There are already interesting frameworks, such as CouchDB, Amazon SimpleDB and many others. A list of NoSQL candiates can be found here.

The session also provides some other interesting information:

• Characteristic of Cloud Computing
• Public and Private Clouds
• Grids vs Cloud

At present Cloud computing is the new Hype and Software Engineers must track this topic!!

[Misc] Software Carpentry

In "Interviews with Innovators" Jon Udell talked recently with Greg Wilson. Greg Wilson is well known for his "Software Carpentry" courses. These courses did not focus on computer science students but mainly on students from other scientific disciplines like Chemistry, Physics or generally engineering studies. His goal in the "carpentry" courses was, as I understand it, to teach scientists who need Software for their work the essential tools and practices. I have the feeling, that this is pretty similar to our "best practice" efforts like our websites, this blog and the book.

However, the motivation is very interesting. One nice example he gave comes to my mind: He occasionally noticed that scientists (using apparently Matlab and the like) use functions mainly for code that is not used any more. Pretty counterintuitive? Well: they use to write the code (as it is possible in many scripting languages also e.g. in Python) in "Spaghetti" script style; as soon as they make major updates they put unused code (that they still want to keep for some purposes, because they also are not aware of versioning tools) into a function, because code in a function is not executed automatically. Nice approach ;-)

However, aside these extreme examples there is, in my opinion, a lot to learn also for education in "regular" computer science classes. As Wilson puts it in an example:

"The research money and PBS Nova programs focus on artificial hearts when in fact all the increase in longevity comes from clean water, anti-smoking campaigns, better nutrition, vaccination and the like. These routine public health measures that no longer are exciting, so they are actually loosing ground."

The same is probably also true in Software Engineering education: 95% of  engineering, but probably also of IT students will not develop the next "Google" but some Web-Forms that connect to a database and produce some reports. But this should be done in an efficient and maintainable way.

I believe this is an interesting thought: we write develop and focus on the latest "cutting edge" technologies, probably leaving the majority of developers behind and probably even worse: confusing them more every day with always new approaches and tiny improvements instead of focusing on the problems the majority of developers and companies have.

Listen to the interview and share your opinion!

[Tech] Distributed SCM: Playing with Repos

As some may have noticed, I migrated nearly all my projects in the last year from Subversion to Mercurial (and GIT). Step by step, as I am rather conservative with changing to new technologies, particularly when they are at the heart of the project. And changing the SCM is sort of a surgery on the open heart.

However, after nearly a year of experience I must say, SCM was (for me) never easier and more enjoyable than with distributed SCMs, particularly with Mercurial. Excellent documentation, easy and straightforward to use. Yet these days I was asking myself: If I would have to name one outstanding feature that would convince me to change from a centralised system like Subversion to DSCM, what would it be?

The answer might be surprising, but for me it is clearly this: No headache and fear when working with the repository any more. What do I mean with that? Well: I was never a Subversion guru and everytime I needed to do an operation I did not do very often (branching, merging) I was sweating. Should I press the button, am I making a mistake? What exactly do these options mean in the SVN client? Did Eclipse now mess up the local copy? Should I commit? After all, you are always working with the repository. If you mess up, you have a problem, and all team members with you. Not a nice procedure.

But with a DSCM there is no master repository, hence in case of doubt I make a clone, play around with the clone. Should I mess it up, I delete the clone and nothing happened. If everything is fine I push the results. This is for me personally the most essential feature of systems like Mercurial. I can play around even with esotherik plugins and features without the fear to destroy anything. This also makes learning for new users way easier.

What is your opinion?

[Pub] Best-Practice Book and the New Year

Some of you might already have noticed, that we were not very active in blogging the last months. The reason is, that (most of us) were heavily involved in finishing our "Best Practice Software Engineering" book that will be available Feb/March 2010. The publisher is Spektrum Akademischer Verlag (Springer), the book is in German.

It was a lot of work and required most of our publishing energy. I believe the result is good and I hope that it will be useful for some of you.

A detailed description of the book can be found at the publishers website.

If you are as enthusiastic as we are, you can even pre-order it via Amazon ;-)

So, for now, I want to thank all readers of our Blog, hope you had a successful 2009 and wish you all the best for 2010. Looking forward to comments from you about our book and upcoming blog posts.

[Tech] Simple Java Template Engine

Template engines are widely used in Web Frameworks, such as Struts, JSF and many other technologies. Apart from classical Web Framework, template engines can be very useful in integration projects. In an actual integration project that deals with a lot of XML data exchange, I discovered the Java Template Engine Library FreeMarker. This Open Source Library is a generic template engine in order to generate any output, such as HTML, XML and any other user defined output based on your given template.

"[...]FreeMarker is designed to be practical for the generation of HTML Web pages, particularly by servlet-based applications following the MVC (Model View Controller) pattern. The idea behind using the MVC pattern for dynamic Web pages is that you separate the designers (HTML authors) from the programmers. Everybody works on what they are good at. Designers can change the appearance of a page without programmers having to change or recompile code, because the application logic (Java programs) and page design (FreeMarker templates) are separated. Templates do not become polluted with complex program fragments. This separation is useful even for projects where the programmer and the HTML page author is the same person, since it helps to keep the application clear and easily maintainable[...]"

I think HTML is one application area of FreeMarker. Consider 3rd party systems providing APIs consuming XML data or their own data structures. Construct their data format in the code is a grubby approach and furthermore the code becomes not maintainable. Using such a library you can manage your data exchange template outside your code and produce the final data by using the template engine. I see such template engines as classical transformers as in an Enterprise Service Bus:

In the above exmple you see, that you can use placeholders in your template files, which will be replaced by the real data when the transformation takes place. FreeMarker provides enhanced constructs such as if statements, loops and other stuff which can be used in your template files.

Template engines are often used in Web Frameworks, but the usage of template engines is also very useful when you must produce specific output for other systems.

[Tech] Integrate Tests as a Language Featuere?

The blog of Cedric Beust (author of TestNG and captured by Google) is always an interesting read.

His last posting discusses the question if generic test features should be included into the language:

http://beust.com/weblog/archives/000522.html

He mentioned an interesting D feature. Personally I think a tighter language integration is useful for small projects. Nevertheless it should be easy to switch to the best testing tools (as TestNG) in bigger projects.

What do you think?

[Misc] Subversion turns into an Apache Project: so what?

Since a few days it is official: The Subversion project has submitted to become an Apache project. It seems that the incubation phase will start soon. Now my question: Subversion is conceptually dead, so what difference does that make? Ok, let's discuss this a little more in detail:

The thing is: most developers (even myself) meanwhile understand the concept of DSCM systems and all available projects are stable, fast, have good communities and are reasonably documented. Even tool support (IDEs, ...) is decent. Having understood DSCM I wonder why I would want to go back to a centralised system like SVN. There is no benefit in there for me. If I want to work server based so be it: I can do this with Mercurial for example in BitBucket, with Git in GitHub or by simply installing the DSCM on an arbitrary server that has ssh access.

I had a discussion with an Apache commiter recently about this fact and about the future of Subversion. He believed, that Subversion could (or better should) go through a complete redesign to embrace features provided by distributed source code management (DSCM) systems like Bazaar, Mercurial or GIT. I personally question this future of Subversion. We already have three pretty good systems and a very competitive game is played here since the last two to three years. Subversion would start with a delay of probably three years. Until a stable version of a (partly) distributed SVN is out, all other systems will be settled and far ahead.

There is, however, one major feature DSCM-systems can not provide by definition: this is collaboration via locking. This is an important feature for collaboration on (large) binary files like Photoshop documents, multimedia files, vector graphics and the like. Merging of such documents is practically not possible, but many (software) projects partly rely on a significant number of documents of that sort. Keeping those in a DSCM system is not the best idea. My future scenario for distributed (software) development hence consists of two repository types: a distributed one for sharing text-based files (like sourcecode) and a centralised one that provides versioning and a very good locking (check-in/out) support for (large) binary documents.

Now as I understand it, Subversion is neither really good in locking nor management of binary data either. Also tools-support for non-programmers (who often work with such binary documents) is not so great. So what is the future of Subversion? I believe already today it is pretty much a legacy like CVS. Off course, there are so many projects using Subversion, that we will probably have to deal with it for the next decade (not that I would like to). However, the migration wave has started and most new projects will use one of the mentioned DSCM systems. How could a re-write of Subversion help? Well, the principles are so different that Subversion with distributed characteristics would be either a new project (and I doubt that we need a forth DSCM system, as mentioned above) or would keep a lot of the disadvantages of the old system.

But maybe Subversion could focus on the locking-based approach: this is a very much needed feature for many projects and I also do not see much competition (in the Open Source environment) here. A good repository for binary data could be a reason to stick with Subversion for parts of the development efforts.

Your ideas?

[Tech] 7 Languages in 7 weeks

Dear Readers,

als you are all interested in programming languages I would like to point your interest to this link which I was pointed at (lots of thanks to the source!):

http://rapidred.com/blog/seven_languages

It is from the blog of Bruce Tate we all know as one the Java Experts and his stunning books.

As far as I know he started an interesting project because he was also interested by the polyglot language area. As I heard he raised a vote about the topic and the languages about his next book! The vote together with his opinion lead to the following languages which I would like to comment on:

• Ruby -> my personal favourite. Perhaps not the coolest now but the expressiveness and the DSLability for me is outstanding.
• Io -> Possibly the newest and coolest because the vm / object approach looks interesting.
• Scala -> Good to have Javas crown prince in here because we all have to learn it.
• Erlang -> My multiprocessor king (even if it struggles with strings. argh). Especially hot in the #nosql database scene.
• Clojure -> I already posted about the great clojure. I really love it although its really hard to learn.
• Haskell -> Good that they / he included the right educational functional concept.
• Prolog -> This surprised me a little. But Bruce writes that he wants to stretch the readers. And I never thought this could go with a nearly 40 year old language.
  

So have a look on this book at http://pragprog.com. It's is a definite buy for me even if it hasn't been written yet.

[Arch] Resource for Software Architecture

I've found a realy good resource for german audience about software architecture hosted on MSDN. On the MSDN Architecture Center you'll find:

• Actual news and trends about software architecture
• Basic information about software architecture (concepts, styles, etc.)
  
• Podcasts
• Tool Previews
• A free english architecture journal
• Forum and Knowledge Base
• Tips and Tricks
  

Advance your architecture skills by looking at this resource. It is worthwhile itself to make a view to this resource.