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.

So, here is my list of distinctive features:

BPMN 2.0 support I took quite a lot of time for this spec to arrive, but it’s finally here. The biggest step ahead comparing with BPMN 1.x is execution model – no more BPEL, you can use the same diagram for modelling and execution, and it has proper xsd schema! Of course, it won’t solve all round-trip headaches, but I think it’s quite important improvement. XML describing BPMN 2.0 process consists of nodes definitions and transition definitions: Activiti is one of the first BPM engines offering BPMN 2.0 support. Currently not all nodes are supported, but the list includes:
* exclusive and paralell gateways  

  • timer boundary and intermediate events (timer start event almost ready)    

  • various tasks: script, user, service, manual, rules, receive    

  • error events and handling them    

  • subprocesses (both embedded or not)     Not all of these nodes are fully defined in spec – e.g. it does not describe how service task invocation should look like. Therefore, Activiti comes with a set of custom extensions. They are meant to be as non-intrusive as possible – to make processes more portable. One of most commonly used are ones for describing service task behaviour: Another useful extension enables to associate html form and candidate user with user task: One of nice features of BPMN 2.0 is also providing xml schema for describing process diagram – aka Diagram Interchange. This enables good engines (such as Activiti ;)) to generate process diagram just on the basis of xml definition – which makes importing processes modelled in some external tool much easier. It looks like this: Maybe not too beautiful, but usable.

Goal of supporting full BPM cycle

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.

Easy to embed and extend, also by quasi-REST API

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

Activiti comes with capabilities allowing for integration with three most popular open source integration frameworks:

  • Mule ESB – integration is written by MuleSoft
  • SpringIntegration, contributed by SpringSource
  • last but cetainly not least: Apache Camel – which is contributed by TouK ;) – it’s still work in progress, but I hope to write a blog post soon about integrating Camel & Activiti

This allows to build processes that are closer to orchestration than simple workflows, containing only (or mostly) human tasks. Each of these integration frameworks comes with a vast collection of adapters using all popular (and not so popular) communication protocols. This allows process engine to concentrate on the process, and not on the communication details.

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.

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How to automate tests with Groovy 2.0, Spock and Gradle

This is the launch of the 1st blog in my life, so cheers and have a nice reading!

y u no test?

Couple of years ago I wasn't a big fan of unit testing. It was obvious to me that well prepared unit tests are crucial though. I didn't known why exactly crucial yet then. I just felt they are important. My disliking to write automation tests was mostly related to the effort necessary to prepare them. Also a spaghetti code was easily spotted in test sources.

Some goodies at hand

Now I know! Test are crucial to get a better design and a confidence. Confidence to improve without a hesitation. Moreover, now I have the tool to make test automation easy as Sunday morning... I'm talking about the Spock Framework. If you got here probably already know what the Spock is, so I won't introduce it. Enough to say that Spock is an awesome unit testing tool which, thanks to Groovy AST Transformation, simplifies creation of tests greatly.

An obstacle

The point is, since a new major version of Groovy has been released (2.0), there is no matching version of Spock available yet.

What now?

Well, in a matter of fact there is such a version. It's still under development though. It can be obtained from this Maven repository. We can of course use the Maven to build a project and run tests. But why not to go even more "groovy" way? XML is not for humans, is it? Lets use Gradle.

The build file

Update: at the end of the post is updated version of the build file.
apply plugin: 'groovy'
apply plugin: 'idea'

def langLevel = 1.7

sourceCompatibility = langLevel
targetCompatibility = langLevel

group = 'com.tamashumi.example.testwithspock'
version = '0.1'

repositories {
mavenLocal()
mavenCentral()
maven { url 'http://oss.sonatype.org/content/repositories/snapshots/' }
}

dependencies {
groovy 'org.codehaus.groovy:groovy-all:2.0.1'
testCompile 'org.spockframework:spock-core:0.7-groovy-2.0-SNAPSHOT'
}

idea {
project {
jdkName = langLevel
languageLevel = langLevel
}
}
As you can see the build.gradle file is almost self-explanatory. Groovy plugin is applied to compile groovy code. It needs groovy-all.jar - declared in version 2.0 at dependencies block just next to Spock in version 0.7. What's most important, mentioned Maven repository URL is added at repositories block.

Project structure and execution

Gradle's default project directory structure is similar to Maven's one. Unfortunately there is no 'create project' task and you have to create it by hand. It's not a big obstacle though. The structure you will create will more or less look as follows:
<project root>
│
├── build.gradle
└── src
├── main
│ ├── groovy
└── test
└── groovy
To build a project now you can type command gradle build or gradle test to only run tests.

How about Java?

You can test native Java code with Spock. Just add src/main/java directory and a following line to the build.gradle:
apply plugin: 'java'
This way if you don't want or just can't deploy Groovy compiled stuff into your production JVM for any reason, still whole goodness of testing with Spock and Groovy is at your hand.

A silly-simple example

Just to show that it works, here you go with a basic example.

Java simple example class:

public class SimpleJavaClass {

public int sumAll(int... args) {

int sum = 0;

for (int arg : args){
sum += arg;
}

return sum;
}
}

Groovy simple example class:

class SimpleGroovyClass {

String concatenateAll(char separator, String... args) {

args.join(separator as String)
}
}

The test, uhm... I mean the Specification:

class JustASpecification extends Specification {

@Unroll('Sums integers #integers into: #expectedResult')
def "Can sum different amount of integers"() {

given:
def instance = new SimpleJavaClass()

when:
def result = instance.sumAll(* integers)

then:
result == expectedResult

where:
expectedResult | integers
11 | [3, 3, 5]
8 | [3, 5]
254 | [2, 4, 8, 16, 32, 64, 128]
22 | [7, 5, 6, 2, 2]
}

@Unroll('Concatenates strings #strings with separator "#separator" into: #expectedResult')
def "Can concatenate different amount of integers with a specified separator"() {

given:
def instance = new SimpleGroovyClass()

when:
def result = instance.concatenateAll(separator, * strings)

then:
result == expectedResult

where:
expectedResult | separator | strings
'Whasup dude?' | ' ' as char | ['Whasup', 'dude?']
'2012/09/15' | '/' as char | ['2012', '09', '15']
'nice-to-meet-you' | '-' as char | ['nice', 'to', 'meet', 'you']
}
}
To run tests with Gradle simply execute command gradle test. Test reports can be found at <project root>/build/reports/tests/index.html and look kind a like this.


Please note that, thanks to @Unroll annotation, test is executed once per each parameters row in the 'table' at specification's where: block. This isn't a Java label, but a AST transformation magic.

IDE integration

Gradle's plugin for Iintellij Idea

I've added also Intellij Idea plugin for IDE project generation and some configuration for it (IDE's JDK name). To generate Idea's project files just run command: gradle idea There are available Eclipse and Netbeans plugins too, however I haven't tested them. Idea's one works well.

Intellij Idea's plugins for Gradle

Idea itself has a light Gradle support built-in on its own. To not get confused: Gradle has plugin for Idea and Idea has plugin for Gradle. To get even more 'pluginated', there is also JetGradle plugin within Idea. However I haven't found good reason for it's existence - well, maybe excluding one. It shows dependency tree. There is a bug though - JetGradle work's fine only for lang level 1.6. Strangely all the plugins together do not conflict each other. They even give complementary, quite useful tool set.

Running tests under IDE

Jest to add something sweet this is how Specification looks when run with jUnit  runner under Intellij Idea (right mouse button on JustASpecification class or whole folder of specification extending classes and select "Run ...". You'll see a nice view like this.

Building web application

If you need to build Java web application and bundle it as war archive just add plugin by typing the line
apply plugin: 'war'
in the build.gradle file and create a directory src/main/webapp.

Want to know more?

If you haven't heard about Spock or Gradle before or just curious, check the following links:

What next?

The last thing left is to write the real production code you are about to test. No matter will it be Groovy or Java, I leave this to your need and invention. Of course, you are welcome to post a comments here. I'll answer or even write some more posts about the subject.

Important update

Spock version 0.7 has been released, so the above build file doesn't work anymore. It's easy to fix it though. Just remove last dash and a word SNAPSHOT from Spock dependency declaration. Other important thing is that now spock-core depends on groovy-all-2.0.5, so to avoid dependency conflict groovy dependency should be changed from version 2.0.1 to 2.0.5.
Besides oss.sonata.org snapshots maven repository can be removed. No obstacles any more and the build file now looks as follows:
apply plugin: 'groovy'
apply plugin: 'idea'

def langLevel = 1.7

sourceCompatibility = langLevel
targetCompatibility = langLevel

group = 'com.tamashumi.example.testwithspock'
version = '0.1'

repositories {
mavenLocal()
mavenCentral()
}

dependencies {
groovy 'org.codehaus.groovy:groovy-all:2.0.5'
testCompile 'org.spockframework:spock-core:0.7-groovy-2.0'
}

idea {
project {
jdkName = langLevel
languageLevel = langLevel
}
}

OVal – validate your models quickly and effortlessly!

Some time ago one of the projects at work required me to validate some Java POJOs. Theses were my model classes and I've been creating them from incoming WebService requests. One would say that XSD would be sufficient for the task, for parts of this va...Some time ago one of the projects at work required me to validate some Java POJOs. Theses were my model classes and I've been creating them from incoming WebService requests. One would say that XSD would be sufficient for the task, for parts of this va...