August 2011 – Efficient technology for the enterprise

BPMN 2.0 Model Interchange with Enterprise Architect, Signavio Modeler and Activiti Designer

I have been using the Enterprise Architect modeling tool for many projects. I like the tool especially due to its quick modeling capabilities and productivity. Therefore is ideal for workshops with participants from IT and business. Performing live modeling together with the domain experts is a very efficient approach to gather accurate information related to processes and IT systems.

So I am very pleased to see that Enterprise Architect 9 now supports the creation of BPMN 2.0 models as well. And even better, models can be easily exported in form of BPMN 2.0 interchange format via Project – Model Publisher in the Enterprise Architect menubar (by the way, import is not possible. :-().
Anyway, I gave it a try and exported a simple model from EA:

To prove that the interchange works, I imported the model in my favorite BPMN tool the Signavio Modeler. This is the result:

That’s not too bad, is it? But it seems that some model details are missing. The dataInputAssociation and dataOutputAssociation, the scriptFormat and the groovy script attached to the ScriptTask were not imported.
It seems that (at least for those two tools) BPMN2.0 model interchange is not yet sufficiently possible.

Update:
I imported the bpmn file into the Activiti Designer Eclipse Plugin version 5.7.1 as you can see below:

The Groovy script was successfully imported, but the dataInputAssociation and dataOutputAssociation was not recognized and therefore removed from the process definition. The original file is solely used for the import. After importing an *.activiti file is created and used as THE model. On saving the model, a fresh BPMN XML file is generated. That is, you loose control over the file at the XML level. I personally don’t like this, as I think executable BPMN files should be treated as source code and need to be fully controlled by developers. A designer tool can help, as long as it does not destroy the orginal source files.

Summary so far:
Sparx Enterprise Architect – Comprehensive modeling, good export, no import
Signavio Modeler – Comprehensive modeling, good export, incomplete import
Activiti Designer – Limited modeling, good export, incomplete import

None of the tools has sound reverse engineering or roundtrip capabilities yet.
For descriptive (level 1) and analytical (level 2) modeling Sparx Enterprise Architect and Signavio Modeler are great.
For executable modeling (level 3) a plain XML editor seems to be the only reasonable option for the time being.

Beautiful Transformations with Groovy

Data transformations are the daily business in ETL and ESB scenarios. If you have a service- or business process boundary it is very likely that data has to be transformed between different representation.
Typical integration scenarios have to deal with a huge amount of different formats (flat file, xml, csv, json, even binary). To make things even worse they tend to change from time to time. Therefore it is important to have tools that are flexible and easy to understand. I found Groovy to be very handy for the transformation job. Let’s have a look at a typical example. Assume we have a flat file in the following format:

Id Product     Amount
 1 Cheese      15
 2 Sausage     2
 3 Bread       3
 4 Butter      4

What we want is an xml representation like this:


  
    
    Cheese
    15
  
  
    
    Sausage
    2
  
  
    
    Bread
    3
  
  
    
    Butter
    4

The groovy script below does the job. The great thing is not only that is works but also that its easy to develop and maintain. A developer can see the source and target structure at the same time.

def reader = new StringReader(flatfile);
def writer = new StringWriter();
def builder = new groovy.xml.MarkupBuilder(writer)

builder.order(){
    reader.eachLine() {
        def line = it
        item(){  
            id(id:line.getAt(0..1).trim())
            name(line.getAt(3..14).trim())
            amount(line.substring(15).trim())
        }
    }
}

println writer.toString();

Thanks to closures an the MarkupBuilder class the transformation can be written in a fluent and intuitive way. Typical other transformations are as simple as that, making Groovy a first choice for data transformations.

The Future of ServiceMix

In the ServiceMix forum there is an interesting debate going on about the Future of ServiceMix. I’ve collected some quotes from the thread. I know it is sometimes dangerous to cite people without giving the full context, but I think it helps to get a rough idea about the direction in which ServiceMix is heading. If you are interested in more details please read to original post.

Quotes:

“The idea is really to make ServiceMix the best possible container for deploying Camel based integration.”

“This also means that there’s really not much to reuse from smx4, so smx5 would have its own new and dedicated svn area.”

“Dropping JBI is already a great step in that direction.”

“Additional things that could be pushed inside ServiceMix 5 would be a Tomcat based container deployment option (for those that don’t need OSGi), a new manual similar to what we have in Karaf (maybe reusing parts of it).”

“For advanced use cases, we should definitely guide users towards Karaf, but for a set of basic things, just using Tomcat and simple WARs may be the simplest thing that works for them!”

“To build the added value I’ve been talking about, we don’t really need the NMR imho. I’m convinced we can do it directly on top of camel without the need for another layer, mostly using Camel interceptors. That way, OSGi is not really needed anymore, though it’s still the best way to deploy Camel routes using Karaf and would remain the main and standlone ServiceMix distribution.”

“Providing a way to easily deploy Activiti would definitely be a good thing. I don’t think it should part of the default distribution, as I’d like to keep it as light as possible though.”

Here is my personal summary:

ServiceMix 5 will primarily focus on Camel.
JBI is finally dead.
Karaf and OSGi will represent the primary runtime.
Tomcat will act as an alternative container.
Activiti will not be integrated.

Consequences:

If you develop for ServiceMix 4 today, focus on OSGi and Camel instead of JBI and ServixMix features since those are the stable parts of ServiceMix.

If you have ServiceMix 3 and JBI solutions in place think about migration towards Karaf and Camel. If you plan to integrate Activiti, make sure the required functionality is not already covered by Camel to avoid unnecessary complexity (see blog post Combining Activiti and Camel).

Combining Activiti and Camel?

It seems that that ServiceMix/Camel and Activiti are growing together as you can read in the blog post Supersize Activiti with Mule ESB and Apache Camel and Deploy Activiti as OSGi Bundles

Activiti has its roots in business process management, whereas Camel comes from the area of enterprise integration. Both allow to describe and automate processes. Activiti uses BPMN, a graphical modeling language with an XML representation for persistence and execution. Camel uses a textual DSL which can also be expressed in XML. Grahpical modeling is also possible with the Fuse IDE.

BPMN example:

The BPMN XML representation is not intended to be written directly and can be hard to read.

Camel example:

from("file://start")
.choice()
  .when(header("goldCustomer").isEqualTo("true"))
    .to("bean:processor?method=grantDiscount")
    .to("direct:out")
  .otherwise()
    .to("direct:out");

from("direct:out")
.to("file://end");

Basically both examples are identical. The Camel example is more explicit and shows more technical details which are hidden in the BPMN example.

Especially non technical users tend to think that a graphical process notation is easier to understand because it looks better. It might be true for simple processes like the one above. But for more complex processes textual DSLs are often easier to write and understand.

Activiti and Camel overlap in many areas. Does it make sense to use them side by side anyway? I think yes, because neither Activiti nor Camel is complete in terms of features required by a fully featured SOA/BPM runtime. Actually they complement each other very well in some areas.

Unique features added by Camel:

Connectivity / Adaptors to connect to external systems using a variety of different protocols
Predefined EIP patterns for message routing

Unique features added by Activiti:

Support for long running stateful processes
Human workflow integration

In order to avoid unnecessary complexity it helps to recall the difference between mediation- and business processes which I descibed in my blog post from 2006.

For mediation processes Camel is appropriate in most cases, even long running processes can be executed as long as they are stateless. But if you need long running stateful processes and human interaction Activiti is an interesting option.

Both Camel and Activiti processes can be modeled using prescriptive and analytical BPMN. The software designer has the responsibility to decide which technology is appropriate for implementing the process. If this is not done right you will end up with unnecessary complexity, limited agility and maintainability.

It would be ideal to have an Open Source SOA/BPM Platform that enables end to end process automation without technology boundaries. As long as this is not available, combining Activiti and Camel is an interesting option. Proper solution design and differentiation of process types is key to create sustainable solutions.