Activiti – are you ready for BPMN 2.0?

From the beginning of this year I got quite involved in project called Activiti. It’s a “light-weight workflow and Business Process Management (BPM) Platform” (according to creators. The project is led by JBPM creators – Tom Bayens and Joram Barrez and is backed by Alfresco and several other companies. I also contributed some small features :) Activiti has already made some noise in BPM world – check this, this, or this, and of course InfoQ.

So, what’s the fuss all about? What makes Activiti special? Of course – it depends what are you comparing it with. My experience involves mainly working with open source BPEL implementation, but I think some points remain valid.

Do you (still) believe that future tools for creating business processes will allow users to get rid of developers? I do not… Unless of course, business people will learn how to code ;) Otherwise what we’ll be left with are some nice zero-coding tools which look great on 15minutes (or event 2hours if they’re exprensive enough) but after running into real-life problems will demand extensive hacking.

Activiti pursues different goal, and proposes developing process cycle layer. Key points of this proposition are:

• zero coding solutions won’t work
• analysts are needed to model the process, developers are needed to create executable processes, and operations are needed to deploy and monitor them
• each of these groups have their own set of tools which they’re familiar with
• so let’s not reinvent the wheel but encourage them to collaborate but use their set of tools

So, how to achieve this? By creating another web application, of course ;) It’s name is Activiti Cycle and it’s meant to encourage collaboration between business, developers and operations, while allowing each of them to use their own, specific tools in their daily job. It’s more like a federated repository of BPM assets, such as Visio Diagrams, BPMN process definitions, maven process projects, deployment packages and so on. These artifacts can be linked, commented and tracked by various process stakeholders and also transformed.

One of biggest pains of BPEL based solutions is that they force you to integrate with the rest of you app using webservices. Fortunately, this is no longer the case. You can embed activiti engine in your (for example) Spring application just by importing few jars and configuring it as any other Spring component:

This is of course great for running processes that handle some Java tasks. What about user tasks? Activiti comes with decent webapps for handling human tasks and monitoring process state: Activiti Explorer – screens shows the list of tasks for a given user:  

Activiti Probe – screen shows monitoring process instance:  

But what if you want to/have to use some other frontend technology? Webapps that I mentioned before are really thin clients – all logic is hidden behind Activiti’s quasi-REST API (I use the word quasi not to be beaten by RESTafarians who will surely point out that Activiti API is just RPC over HTTP…). That means you can embed Activiti in you webapps/OSGi container/any other environment and integrate with frontend webapps using handy JSON/HTTP communication. Which looks more or less like this:

Using (defacto) standards When you create application using Activiti chances are high that you know many (if not all) building blocks & techniques:

• development? Eclipse plugin & maven
• connecting components together? you can choose: spring or (for JEE6 lovers) CDI
• testing? just do your normal TDD (you do it, right? ;)) using Activiti JUnit testing utils

Eclipse plugin includes visual modeler, which enables you to draw executable BPMN 2.0 processes, and fill all needed properties:

It uses Diagram Interchange format, so process diagram layout will remain the same when displaying process diagram in other applications. Testing is also pretty easy, as Activiti comes with good JUnit support. One of small, but important features is ability to simulate the clock – very handy when dealing with long running tasks.

Good integration capabilities

Summary I think it’s quite impressive set of features for a product that is less than year old. And what are Activiti plans for the future? Tom Bayens recently announced that Activiti is going to support some sort of Adaptive Case Management – which is one of top buzzwords in process world. Other goals include:

• asynchronous continuations
• moving towards full support of BPMN 2.0
• extending Activiti Cycle – check Bernd’s Ruecker screencast showing Activiti Cycle approach to handling collaboration between analysts, developers and admins – it’s quite impressive

As for me, I’m finishing adding support for start timer tasks and hope to post something on Activiti-Camel intergration and running Activiti in OSGi environment soon – especially Apache Servicemix – so stay tuned. If you’ve found Activiti interesting, please start with 10 minutes 

Getting started guide, and if you know Polish, you can also have a look at my slides from Warsaw JUG presentation Thanks for reading my first post on this blog – hope you liked it.