contentcentric.org

One of my readers left a comment saying that my previous post left him high and dry when it came to creating the client project for testing his service.

So I put this very quick post together to describe it for him and hopefully for others too.

First this to note here is that there are lots of ways to create a DFS Client spanning both Java or .Net.  This is just one way using Documentum Composer.

So where did the previous post end up.  Well we had created a Documentum Project and within that created a DFS service, exported it as a service archive and deployed it onto a suitable application server. 

So what next?

Create yourself another Documentum Project (File->New->Other->Documentum Project).

Next create yourself a lib folder and in it import (Import->File System) your services remote jar.  This will have been exported at the same time as your service archive.  If you called your service archive samples for example then you would look for samples-remote.jar.

Once imported add it to your java build path (<project>->Properties->Java Build Path->Libraries->Add JARs…  Navigate to your remote jar within your client project and select it.  You should end up with the equivalent of this:-

You also want to make sure you have the right DFS client class path configured.  So whilst you are on this dialog.  Select the “DFS Services Library” build path entry and click Edit…  Select an appropriate library type for your scenario.  I’ve chosen “DFS Remote Client Library with UCF”:-

Click Finish.

Finally you need to write some code to call your service.  There are lots of contexts that your code could execute within; a Main class, a java application, an eclipse application, lots of others too.  I’m a big fan of test-driven development so I like to create Junit tests as these can be automated later and become part of the applications test suite.   Let’s create one of these (File->New->Other->Java->Junit->Junit Test Case):-

Give your Junit test a Package and a Name and make sure you’ve chosen to create a constructor stub.  Don’t worry about the super class warning – just click Finish and you should see this dialog:-

Obviously we do want to add Junit 3 library to the project’s class path so choose to perform that action.  Click Ok. 

Composer should do that for you and open your newly created Junit test case in the java editor.  We now need to add our service orchestration code.   Add a method called test with the following signature shown:-

And then add your orchestration code to that method.  If your not sure how to get started with this then a great place to start here is the client code that ships with the DFS SDK.  Cut and paste in a sample remote client and re-purpose it for your needs by changing the service related calls to use your service.  I’m actually using the DFS Hello World sample for this article.  As you are adding code, especially if you cut and paste a sample, you’ll end up with a bunch of problem markers:-

Because we already configured the project with a DFS class path you can hover over the problem marker in the sidebar and use the quick fix to add the necessary DFS imports.

A good tip here is to note that the moduleName and contextRoot (in the code sample above) must match the equivalent settings that you configured for your services project and that are also specified in the Export Service Archive dialog:-

That is pretty much it.  Make sure your services are deployed and that the server is running and the wsdl for each service is available.

To run the Junit test right-click on it in the project explorer and select Run As->Junit Test.  This will execute your test case using the Junit test framework and display the results.

If you want to debug the code then set a break point in the code and select Debug As->Junit Test instead.

Now it is important to note that DFS supports two modes of invocation; remote – as we outlined above.  But it also supports local invocation too. 

This provides us with an alternative way to test our service code with less fixture than the remote alternative; i.e. without having to deploy it to a server.  

First we also need to add some of the services’ resources to the services project’s class path so that the DFS runtime can find them.  The Ear is configured in such a way that these same resources are available on the class path when the Ear is deployed on an app server.  We are just mimicking this configuration. 

So right-click on your services project and select Properties ->Java Build Path->Libraries.  Click Add Class Folder.  Navigate down your services project.  Expand the Web Services folder and the bin folder.  And check the gen-rsc folder.  Click Ok.   You should see this folder added t0 the build path:-

That’s the services project configured.

Now create another Documentum client project.

This time round make sure you add your service project to the Java Build Path (<client project>/Properties->Java Build Path->Projects):-

As before edit the type of DFS Library Path but select “DFS Local Library”.

There is no need to add the remote jar as we will pick up the service classes directly from the project.

As before add the Junit Test Case.  If you get any compilation errors then quick fix them.  Note, that when you add your services code you must call getLocalService instead of getRemoteService AND you don’t need to register the service context with the ContextFactory ahead of time.  So your service invocation code simply becomes:-

ContextFactory contextFactory = ContextFactory.getInstance();
IServiceContext context = contextFactory.newContext();

ServiceFactory serviceFactory = new ServiceFactory();  
IHelloWorldService service = serviceFactory.getLocalService(
               IHelloWorldService.class, context);

And that’s it.  You are ready to go.  Right-click on the Junit class in the project explorer and select Run As (or Debug As)->Junit Test.

So we’ve walked through creating a remote DFS Consumer and looked at an alternative for creating a local DFS consumers that leverages DFS’s local invocation facility.

As always I await your feedback.  In the meantime…

Happy Composing!

Using DAB the mode de jour was to develop against a Docbase; live, connected, whatever you want to call it.  You nominated a "System of Record" Docbase.  You then went about the business of defining all the artifacts; types, lifecycles, workflows, relations and so on and so forth, that collectively made up your Docapp (a DOCbase APPlication).

Your application(s) code would never execute against these particular artifacts, in this particular Docbase; because they really were just the definitions of resources that your application requires to be present in a production Docbase in order to run correctly. Meanwhile, the rest of your application artifacts; java classes, servlets & jsps, XML, etc, were all managed out of a source control system.

To prepare a content-rich application for distribution. Release engineering (releng) would checkout all the application artifacts, build and package them as an installer or as a war or an ear.  They would then also export the associated Docapp as a Docapp Archive and place with the application package.  These resources were then placed on a download site where customers could find them.

To install the application the customer would use the installer or deploy the war or ear. He would then use DAI to install the docapp archive into one or more production Docbases.

So, that is how it was.  The System of Record for your source artifacts was the Docbase itself.  But what was so wrong with that I hear some of your ask?  Well a few things as it happens:-

1. Having different Systems of Record is just plain wrong, and what made us so special anyway?
2. Versioning semantics for Docbase artifacts is not always the same as they are for source control, complicating development, histories, labelling and snapshoting
3. Releng needed to have and to know Docbases and to construct Docbases processes (not all of which were that automatable) which was hugely burdensome for them

With reference to the versioning semantics.  It is important for us all to recognize that the Docbase is just plain bad at development versioning.  For example, types in a Docbase cannot be versioned but code certainly depends on particular versions of types.  Now if we could have reliably versioned artifacts then we can support explicit versioned dependencies, even when the target environment does not support it. Explicit versioned dependencies allow us to bind code to specific versions of Docbase resources and have those dependencies validated.  The upsides of reliable versioning are hopefully evident.

Recognizing that content management would soon standardize through efforts like CMIS.  Recognizing that this would foster and entire industry of organizations building content-rich applications we knew we would have to address these shortcomings and move more mainstream.

So we built Composer and a system of linked XML-based artifacts and an install process that can transform these XML-based artifacts into Docbase objects, preserving the links by converting them to Docbase links; i.e. OIDs.

No longer is there a need for a "System of Record" Docbase.  Docbase artifacts can now be developed in the same eclipse IDE right alongside all your other application artifacts.  They can also be managed out of the same source control system, giving us reliable version semantics and greatly simplifying the releng process.

OK so we have ironed out that little wrinkle.  Docbase artifacts are now analogous to other source artifacts and therefore we are all now followers of the same development model.   In this respect we’ve become a bit more standard and hopefully removed a big barrier to entry for release engineering departments.  We believe this will help promote EMC|Documentum as the platform for developing content-rich applications.

So what’s next?

In a word "OSGi".

A phenomenon is sweeping the java community in the form of OSGi, a dynamic module system for Java. Most application servers are OSGi-based already.  And this phenomenon will undoubtedly impact the ECM community too. 

OSGi is mature.  It is over 10 years old and has grown out of embedded systems world.  So this is not new technology by any stretch.  It may just be new to some of us.  It is also standards-based. 

OSGi promotes a world of modules (bundles in their parlance) that can be dynamically inserted (or removed) into any live, running system with no interruptions in the services it provides.  Each bundle has versioned dependencies that the system will honour and enforce these.  And a system can support multiple versions of a module at any one time.

For all these reasons (and many others) I believe that OSGi is the perfect fundamental building block for next generation ECM solutions and solution frameworks.

It is also very important to recognize that in this future world of solutions and solution frameworks we may well also see direct, application hosted, manipulation of our XML systems of record.  As well as continuing to support the more traditional offline development model, both will co-exist quite happily side-by-side.  This direct manipulation will be supported by a family of web-based tooling built on the central core of the Composer tooling platform.

But this is still a little way in the future.  Because OSGi will effect how applications are delivered the most noticeable change you will see in the short-term will be to our friend the dar (Documentum Archive) which I believe is already set to become an OSGi bundle.  This will prepare the way for it to be just like every other piece of the solution.  Developed the same way, delivered the same way.  Depended upon, dependent upon others.  Really binding into the application as the vital constituent part that it really is. 

So what conclusions should you draw from this? 

Well if you are considering developing a content rich application (or larger) on Documentum then you need to be following Composer’s lead and adopting model-driven development.  Making XML models a central tenet of your development practices is the right thing to do.  Leverage Composer, the tooling platform, and in particular its EMF-based modelling and your not going to go too far wrong. 

Also getting more involved in Composer, the tooling platform, by extending it for your purposes by adding your own Docbase artifacts would be an excellent way to introduce yourself to the wonderful world of OSGi.

Happy Composing