Configuration based ESB

I think that anyone who read my previous posts can see that I work allot with ESBs - the blog posts were mostly dedicated to IBM, but I work with OSB, JBossESB and some other solutions as well.

I am amazed at just how much work customers invest in ESB development - they build an architecture, build a development team - and usually, 99% of the work they do - is the same across all organizations.

Because everybody are using ESB in the same way - to enforce web services policies - usually security, but also validation, version management, monitoring and a bit more.

So - what do all these off-the-shelf products give us? Not enough.

I believe that a new generation of ESB is in order - one that will not require coding. The ESB should contain a single point of entry for all services in the organization, all will follow a configured validation and enrichment path, and at the end will be directed to the actual service. No coding, no development team - just simple configuration. Should definitely suffice most customers.

I have a few ideas on an architecture of such a thing, and Aluna even has a small product based on open source technologies, that runs with both .net and Java clients.

But that is another story.

WebServices Reliable Messaging

A customer of mine asked me to build a POC of using WS-RM with CXF, C# and Oracle Service Bus. Against my better judgement - I said yes. I know it doesn't work - but I'm always up to the challenge.

Turns out documentation is shitty at best. Vendors provide a one-page demo, using messaging infra or embedded HTTP servers - no web containers or web servers.

So - I have decided to start with .net and CXF and leave the OSB for later.

The pain is installing VS2010 Beta 2 over my machine which had VS2010 Beta 1 - a version that was deleted a couple of month ago.

You can't install VS2010B2 on a B1 computer - you must do a reinstall of B1, then uninstall it, then install B2.

Bloody nightmare.

WebSphere 7 - deployment performance

Well, I'm currently running a migration project from Oracle's OC4J to WebSphere 7. Why 7? Because the customer wants to use JSF 1.2, and EJB 3 - and we decided on going to WAS7 instead of WAS6.1 with the fix packs.

The migration wasn't so smooth - the customer used some proprietary code we had to change. And let me tell you - configuring TopLink to run on WAS is a real pain, especially when some TopLink code is accessed through EJBs and some through regular Java classes from the web tier.

But the real problem was WAS7 deployment. It took forever... We tried running it from RAD7.5 or from the admin console directly - it was painful. It took around 5 minutes, and every configuration action that required application restart took ages to complete.

Turns out the problem lies in the JavaEE5 spec. When you deploy an EAR it needs to look for annotated classes that are marked as EJB and servlets. So deploying a WAR file with a large number of classes and JAR files will be very slow.

There are deployment separation solutions (putting the classes in the app-inf/lib of the EAR instead of web-inf/lib of the WAR) but a quick fix, that fits when you don't use annotated servlets is to add the metadata-complete attribute to your web.xml file (in the web-app tag). It tells the deployer that all of your servlets and filters are configured inside the web.xml file.

See this link for the complete web_app_2_5 XSD description. http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd

WebSphere 7 book by Packtub

Well, I was asked by Packtub to review their new book on WebSphere Application Server 7. It was 3 month ago, but I finally got around to it.

The book starts kinds of slow - downloading WinSCP and Putty, installation on Linux. Not sure this is the most common developer scenario.

And I'm not sure I would learn WebSphere App Server for the first time from a book...

But then the book starts to kick off - Chapter 3 talks about Security. Insane - considering the fact that 90% of the WebSphere administrators I know don't know how to configure security. And they go into detail - configuring LDAP and stuff.

Then they go on on Tracing, Performance - what everybody should know - and they explain it in a step-by-step manner.

So from my side - I think it's a good book. Especially since so few people really understand how to work with WebSphere App Server.

On the down side - there is no Web Services chapter. With the new Web Service pack (available in WAS 6.1 and builtin in WAS 7) it's impossible to configure web services in WAS, and it's a shame the book didn't cover this complex topic (especially web services security).

C# String GetHashCode()

It is very difficult to Java developers to write C# code. Not because of the language - they are pretty much the same. But it turns out you make basic assumptions which are just not true.

We develop C# code that access services deployed in WebSphere ESB and send messages in WebSphereMQ. The sender creates a message identifier, that consists of the sender id, object type and more. The listener creates the same identifier, and listens to the queue with this identifier.

Suddenly - the identifier the listener and the sender create is different.

Turns out that the problem lies in the fact that the sender is a 32bit machine, and the listener runs on a 64bit machine.

Why is that a problem? Because in .net, code is not cross platform - not even between Windows environments - since the GetHashCode() function of String is not cross platform - and works differently on 32bit and 64bit machines.

Unbelievable!!!

Anyway, we wrote our own Hash function, that simply copies the java.lang.String hash() function (every JDK comes with src.zip, where you can find the java.lang.String code).

3 hours of my life wasted...

WebSphere Process Server - skipping steps in the process

A customer of mine has decided to build an application that can monitor his processes, instead of the regular WPS supplied tool.

His main concern was skipping steps. Turns out that when a process has executed a specific activity, and this activity is in a special position (like user task) - an outside application can cause a skip in the process.

I have developed a short demo for this, and I'm enclosing the main method here. Just make sure to disable the process security before running it - or you'll get a non authorized exception...

// Connect to the server

Properties props = new Properties();

props.put(Context.PROVIDER_URL, "iiop://localhost:2811");

javax.naming.InitialContext ctx = new javax.naming.InitialContext(props);

// Lookup the BusinessFlowManager. If you get casting exception - read the InfoCenter - you need to add some JARs to your code - it's WPS/ProcessChoreographer/client/bpe137650.jar

Object lookupResult = ctx.lookup("com/ibm/bpe/api/BusinessFlowManagerHome");

BusinessFlowManagerHome processHome = (BusinessFlowManagerHome) PortableRemoteObject

.narrow(lookupResult, BusinessFlowManagerHome.class);

BusinessFlowManager bfm = processHome.create();

// Replace with any process id

ProcessInstanceData pid = bfm.getProcessInstance("_PI:90030124.f71386d4.dbed54f5.5d84025c");

// Replace with any activity name

ActivityInstanceData aid = bfm.getActivityInstance(pid.getID(),"Wait");

// Skip to the specific activity

bfm.skipAndJump(aid.getID(), "TargetActivity");

AspectJ 1.6 with runtime weaving and WPS 6.2

Well, I haven't blogged in ages, and it's not because I lacked things to share...

Anyway, almost all of my WPS customers are looking for some level of polymorphism (or process templating) and AOP. For the first - I currently have no solution. For the second - here comes...

1. Download AspectJ 1.6.2.
2. Since it's been a long time since I worked with AspectJ, I wrote a small program in Eclipse. I just made sure that it used the WPS JDK - to make sure the -javaagent flag works. It does. However, you can't use it when your eclipse works with a Sun JDK. So - add a -vm to your eclipse.ini file. (See here for details: http://wiki.eclipse.org/Eclipse.ini
3. Now, I opened a new WID module, wrote a short process.
4. I also created a small Java Project, which will create a JAR in the WAS/lib directory. It will include my aspects and the aop.xml file (under the META-INF directory)
5. I started my WPS server, and put the -javaagent flag in the startup options. WAIT!!! Since WPS security is enabled by default, and the aspectJ weaver is located outside the WPS libraries - java security policy won't let it load - and you can't start your server!!! Copy the jars into the WPS lib directory. Just make sure you don't override existing files (aspectj.jar should be in WPS/lib - just rename it to something that doesn't end with JAR)
6. That should be it - the aspects now work. However, how do we tie them to the process itself?
7. It seems that the way WPS works is that for every BPEL activity there is a class in the com.ibm.bpe.engine package, and the doActivate method is called. So our pointcut will need to look like this - @Before("call(void com.ibm.bpe.engine.BpelActivityKind*.*(..))") - this should also explain why we put the aspect in the JAR in the WAS/lib directory - it should be in the correct class-loader level.
8. Well the only thing missing is the actual pointcut - but it's too late for that - will publish it tomorrow morning... Don't hold it against me. I will also post the required code to get which Activity we are on. Quite cool...