Enterprise BPM

jBPM 4.4 is OUT!

2010-07-19T22:40:00.000-05:00

The wait was long yet worth the while. jBPM 4.4 is now available for download. This new version resolves nothing short of 108 issues including feature requests and bugs. Compared to v4.3, with 47 issues, and v4.2, with 40, this release is a double pack.

Here comes the list of enhancements to the jPDL notation.

foreach structure: spawns concurrent paths of execution for each element of a collection.
assign activity: copies a source value to a target location.
variable declaration: declares a process variable with optional initial value and history trace.
Most elements can appear in any order within their parent element.
Improved documentation readability.

There are new APIs available to application developers.

Activity represents a step in the process.
Transition represents a link between activities.
OpenExecution.getActivity() returns the activity being executed.
ExecutionService.createVariable() creates a process variable and optionally enables history tracing.
HistoryService.getVariable() retrieves the latest value of a history-enabled variable.

Of particular relevance among the 64 bugs fixed, web console reports no longer fail in Tomcat. The installation script now generates a configuration that employs a global data source instead of connecting directly to the database. This makes 4.4 the most cat-friendly jBPM yet!

Special thanks go to Hui Sheng Xu and to Maciej Swiderski who made profound contributions to this release.

Hope you find this release more stable and useful than ever. Should you need help or have any feedback, stop by our discussion forum.

WANTED: testers for upcoming 4.4 release

2010-06-18T03:12:00.000-05:00

The jBPM gang are planning to release version 4.4 next Monday. Most issues reported against this version are done, Hudson looks better than ever and, importantly, it has been almost six months since the previous delivery.

Please help us test this new release before it hits the streets. The snapshot of the distribution is available from the JBoss snapshots repository. The existing user guide provides installation instructions.

Should you have any comments, questions or concerns, you are most welcome to voice them in the discussion forum.

Announcing jBPM 5

2010-04-16T16:14:00.000-05:00

Over the last few years, we have accumulated a lot of knowledge and experience in various BPM-related projects here at JBoss, and in an effort to consolidate that, we would like to combine our efforts in what will be the next generation BPM platform, called jBPM 5.

jBPM 5 will be based on the combined experience of jBPM and Drools Flow (and related projects like RiftSaw and Overlord), and will bring together the benefits of both solutions (and much more). As part of this process, we would like to ask you, our community, for feedback and assistance on this.

The architecture of jBPM 5 builds on the experience that was built up over the past few years based on our customer feedback as well as strong community involvement. It will continue the vision of all of the constituent projects, so large parts of the architecture that we are presenting here will probably not come as a surprise to you, either because it already exists in a current project or because it has been on the roadmap for quite some time (BPMN2 for example).

Nevertheless, wide feedback is very important to us, and we have therefore constructed a Request for Comments document which describes (what we believe could be) the new architecture of jBPM 5. Not only this includes an overview of the most important components, but also some of the key characteristics. We will roll out a roadmap for jBPM 5 based on this architecture and the received comments.

Now is the time for the community that has helped shape these projects so well in the past to do so again. We will welcome any feedback to this proposal, either by sending an email to the jbpm-dev mailing list or by adding a comment to the request document directly. If you would like to subscribe to the jbpm-dev mailing list or browse the archive, please visit the list information page.

jBPM Continuous Integration Reports Now Publicly Available

2010-04-07T11:12:00.001-05:00

Thanks to the restless Quality Engineering team at JBoss, the continuous integration reports for select projects are available to the public. Here is the most recent token of the company's long-standing tradition of openness and freedom. Not only is the jBPM source code open, but also the development forum, version control system, issue tracker, binary repository and now even the continuous builds. jBPM bares all!

The jbpm3 jobs form a matrix with three axes: jdk, container and database. The jdk and container axes are merged together in order to cover the most ground with the least configurations.

jdk	container
sun 1.4.2	jboss 4.0.5
sun 1.5.0	jboss 4.2.3
sun 1.6.0	jboss 5.0.1

The database axis is arranged as a vector to allow for parallel testing; each jdk-appserver couple is executed against each configured database. This organization is quite effective: each job takes only 25-30 min to run.

Hope this new stream of information will tickle your curiosity about the engineering aspects of the project.

Open letter to the jBPM community

2010-03-26T12:40:00.002-06:00

Dear jBPM community,

We at JBoss would like to inform you that Tom Baeyens and Joram Barrez have left their position as project lead and core developer respectively. Tom has sharply led jBPM and made it grow into a recognized brand in the business process management arena since joining JBoss back in 2004. Joram brought solid deployment expertise and made profound contributions in areas like performance, integration and standards compliance. Please join us in wishing them the best of luck in their future endeavors.

Despite the sad news, the people at JBoss would like to pledge our commitment to advancing the jBPM project. While this change will undoubtedly impact the jBPM 4 releases in the immediate future, we are busy reorganizing the existing development team and bringing in new blood. The project will continue to pursue the vision of delivering a first class embeddable BPM engine, supporting native BPMN 2.0 execution, providing friendly yet powerful design and monitoring tools, and striving for maximum flexibility and expressiveness in the process language as well as the framework API.

During the flux phase, I will assume the leadership of the jBPM project, make sure the assets remain safe and keep answering your questions in the project forums. As a long-time developer and promoter, my quest for bringing the premier open-source BPM engine to you will continue.

Should you have any questions or comments regarding this announcement, please join the discussion in our user forum.

Sincerely,

Alejandro Guizar
Senior Software Engineer
JBoss by Red Hat

jBPM on Fedora

2010-01-07T00:04:00.002-06:00

Ever since I switched from Windows to Fedora back in August 2008 I have not thought about going back even once. Never before had I seen so many engineering feats put together:

efficient system resource usage
quick file manipulation
consistent file system layout
isolation between processes
capable, integrated command set
uniform software distribution and installation
so much more!

Many a challenge has come my way, though it always met a clear, rational, repeatable solution, thanks to the enthusiastic community. No reboot-cures-all kind of deal.

Anyhow, during this time I had several occasions to put jBPM under the glass and check how it behaves in combination with various databases in this environment. Setting up any database in Fedora is not always straightforward due to missing, outdated, or overly generic documentation. After spending some time connecting the dots, I was suggested to document my proceedings for future reference.

The database installation guides listed below are the result of the documentation effort. Be assured they have been validated at least twice, each time I upgrade to a new Fedora version.

If you are looking to run jBPM or any other database application on top of an avant-garde, free and open operating system, these guides should be helpful.

Happy new year!

Update. I added an installation guide for Oracle.

E-mail support in jBPM 4

2009-07-15T00:35:00.001-05:00

Today I would like to talk about one of the many automatic activities that jBPM 4 provides out of the box: sending emails.

For those of you who have been using jBPM for a while, you may remember that jBPM 3 offered you e-mail support in the following incarnations.

node step visible in the process diagram
action handler event not shown in the diagram
task notification when an actor is assigned a task
task reminder at specific intervals after task creation

The above functions were all implemented on top of a common infrastructure. Not all of them exposed the underlying capabilities consistently, tough. Moreover, the infrastructure was not modular. The template (entity), producer (control) and session (boundary) components were mixed together. Critically, more advanced capabilities were missing.

In the latest iteration, the email feature received input from a larger and more heterogeneous group of people, consisting of the core jBPM team, one consultant from a sister company and two community members. It took some time and many a compromise to come up with a solution that everyone liked. Nonetheless, the end result was much better than any of the participants would have achieved separately, in a true open source fashion.

The design criteria were:

Clean, concise syntax
Customizable mail composition
Dynamic content templates
Composite payload: HTML and attachments
Multiple SMTP servers with address filtering

The diagram below depicts the design that realizes the above requirements. Immediately following is a description of the interaction.

The client of the mail subsystem requests its associated mail producer to produce email messages, reading variables from the given execution. The producer contains or references a template (not shown) which specifies the recipients and the content of the message.
The client retrieves the (shared) mail session from the environment and hands it the produced email messages. At this point, work from the perspective of the client is done. The rest is handled by the mail session.
The mail server is configured with one or more SMTP servers, each with separate filter and transport settings.
A mail server only sends messages to the addresses accepted by its filter.
Each mail server encapsulates the mail properties required to create a javax.mail.Session and retrieve the corresponding transport.
The transport is responsible for ultimately delivering the messages to their recipients.

Both MailProducer and MailSession are interfaces, allowing for customizable mail composition and delivery. The mail subsystem provides facilities for a client to read an arbitrary mail producer from a DOM element. In turn, the mail session implementation can be changed through the existing configuration binding mechanism provided by jBPM.

For more details on the mail features, please refer to the jBPM developers guide. In a future post I will focus on the mail usage model. Talk to you soon!

jBPM 3.2.6 is out!

2009-03-11T17:23:00.004-06:00

Delivering on our two-month timeboxed releases, I am pleased to announce jBPM 3.2.6, available for download at the usual place. This new version delivers many bug fixes (27) and updates (22) back to the community that took the time to report them.

Here is a scoop of the issues resolved over this cycle.

Continous integration with PostgreSQL
Serializable values in process variables
Prevention and handling of optimistic locking exceptions
API to query failed jobs
Basic performance evaluation
Compatibility with database schema from version 3.2.2

Bernd Ruecker of Camunda GmbH deserves a special mention for his contributions to this release. Thanks!

I hope you enjoy using this release as much as our team did producing it. Either that, or at least not spend any night on stabilization, as I did :-)

Data source configuration in jBPM 3.2

2009-01-17T11:11:00.010-06:00

Starting from version 3.2.4, jBPM is distributed as a Java-based installer for easy product setup. The installer lets you fill in the following parameters.

1. Installation directory
2. Components to be installed (see screenshot)

Standalone
JBoss integration
Optional Eclipse / JBoss AS downloads

3. Target database
4. JBoss AS directory, if you already have one

The target database selection currently includes HSQLDB, MySQL and Sybase, with PostgreSQL, Oracle and MS SQL underway. Selecting a database is as simple as clicking your choice in the appropriate screen. Configuring jBPM with the appropriate parameters for your database is slightly trickier. This post will guide you though it.

The installer will put the jBPM enterprise components in the deploy/jbpm directory of your server profile. You will find a jbpm-database-ds.xml file there, where database corresponds to your selection in the installer, of course. Let us take MySQL as example. The contents of the installed file are listed below.

<xa-datasource>
<jndi-name>JbpmDS</jndi-name>

<xa-datasource-class>
com.mysql.jdbc.jdbc2.optional.MysqlXADataSource
</xa-datasource-class>
<xa-datasource-property name="ServerName">
localhost
</xa-datasource-property>
<xa-datasource-property name="PortNumber">
3306
</xa-datasource-property>
<xa-datasource-property name="DatabaseName">
jbpmtest
</xa-datasource-property>
<user-name>jbpmtest</user-name>
<password></password>
...
</xa-datasource>

You will probably want to edit the server name, database name, user name and password before launching JBoss AS, otherwise you will get database connectivity exceptions. The remaining settings have worked for us in our test environment and are our general recommendations. In case you want to further tune the data source, the available settings are documented in the JBoss AS configuration guide.

Apart from the data source, the installer places the JDBC driver of the target database in the deploy/jbpm/jbpm-service.sar directory, provided that the driver is freely distributable. Otherwise, you will need to obtain and install the driver yourself, according to the instructions provided in Appendix B of the aforementioned guide. Free open source database users have it easiest, which is only fair :-)

A new LAMP: Linux, Apache, (Java) Middleware and PostgreSQL

2009-01-12T00:31:00.009-06:00

If you work in the software industry, particularly if you consume and/or provide free and open source software, you will undoubtedly have come across the LAMP acronym (otherwise, you just did). LAMP is an emblem of free software. Indeed, many web sites out there rely on this versatile software stack.

Nonetheless, for us Java devs, the P is excluding, be it PHP, Python or Perl, whereas the M generates mixed feelings. Of course, the Java platform was freed only recently, which accounts for its absence from the free software stage. Anyhow, Java is free nowadays. Wikipedia states the following about LAMP.

the combination has become popular because of its low acquisition cost and the ubiquity of its components, which come bundled with most current Linux distributions.

OpenJDK is available from the package repositories of Fedora 9 and Ubuntu 8.04. I have confirmed it can be installed as easily as Apache, MySQL or PostgreSQL in those Linux distributions and undoubtely in others as well.

What about the database? Like I said, mixed feelings there. MySQL claims to be the world's most popular open source database, whereas PostgreSQL is allegedly the world's most advanced open source database. 'Nuf said. No, really.

In recent experiences with jBPM testing, the easy setup and low maintenance requirements of MySQL have been a pleasant surprise. No doubt it is more popular. Conversely, the PostgreSQL community's ability to roll out new features (foreign keys, views, subselects, transactions and, more recently, two-phase commit) well in advance of its open source competence, makes it a distinctly compelling product.

Free software is about choice. Time for a new LAMP?

XA data sources and jBPM

2009-01-05T12:51:00.001-06:00

One handy and often overlooked feature of jBPM 3.3 is the ability to customize the services provided by the jBPM context, and even add your own. The user guide documents the feature in Chapter 6: Configuration. Services are an abstraction layer from the operational environment and allow jBPM to run standalone or inside an EJB container.

When running inside an EJB container, the message service is bound to JMS and the scheduler service to EJB timers. Some supporting enterprise beans need to be deployed for the services to work. In the Hibernate configuration the JDBC connection properties are replaced by a server-provided data source.

When your process definition makes use of the message or the scheduler service, the JMS connection factory or the EJB timer service are enlisted as resource manager in the container-managed transaction, in addition to the jBPM data source. When more than one resource manager is enlisted in the same transaction, all resource managers are conceptually required to support XA (two-phase commit) unless the last resource commit optimization is in effect.

In JBoss AS, the JMS connection factory is XA capable and poses no problems. However, the EJB timer service relies on a data source to persist timer data. The data source is by default bound to DefaultDS, a local (as opposed to XA) data source. If the jBPM data source was also local, the transaction manager would reject the second local resource and roll back the transaction. There are at least three approaches to a solution to this problem.

Enable multiple resource manager enlistement
Associate both the EJB timer service and the jBPM persistence to a single data source
Make jBPM use an XA data source

The first two solutions require end users to modify their JBoss AS configuration. However, the aim of jBPM is to provide a seamless out-of-the-box experience. End users should not be required to alter their configuration just to get the product to work. Providing an XA data source is therefore the only viable option.

Whereas most databases provide working XA data sources, most are not as proven as the standalone JDBC driver is. All of them work in the absence of errors, but some of them do not recover properly in exceptional scenarios. The currently supported databases/drivers along with their known XA support are listed below.

HSQLDB
XA data source: no
EJB container integration not available.

MySQL
XA data source: yes
Backend does not support XA - coming in 6.0 with the Falcon storage engine.

PostgreSQL
XA data source: yes
Backend and driver support.

Sybase
XA data source: yes
Backend and driver support. Distributed transactions must be enabled in the backend.

Conclusion. EJB container integration is at the mercy of the target database. Choose carefully!

New year, new blog

2009-01-02T13:56:00.000-06:00

After a long time of putting off blogging for next year (where next is always current plus one), I have finally came around to sit down and do it.

Rather than throwing subjective comments about technology, the software industry and everything, I want this blog to offer objective information about BPM, enterprise Java and related technologies. Of course, JBoss jBPM will be at the center.

Having the goal concisely phrased, I wish anyone reading this entry a succesful 2009.

* Xihumolpilli *