Business process execution Language support or BPEL is at the top of every enterprise SOA punch list. It's an XML-based language designed to support long-running complex business transactions in the form of orchestrated Web Service interactions. Like most XML formats, you wouldn't want to construct and debug a process of any complexity by hand and an "engine" is required to recognize and execute BPEL.

This is where the tool vendors come in and Active Endpoints, Inc. has a design tool and engine product combination that we'll cover in this review.

ActiveBPEL Designer
The designer is a world-class visual environment for working with BPEL-based processes. ActiveBPEL Designer is built on the seemingly ubiquitous Eclipse extensible development platform and, as you can see in Figure 1, has an interface with a clear and logical layout.

The "Navigator" tab in the upper left region displays a hierarchical view of projects, folders, and files in the workspace. To the right of the Navigator is the "Web References" tab. This tab contains a registry of namespaces, messages, type definitions, and sample data, used in BPEL processes. It's populated automatically as WSDL files and XML schemas are added to the workspace. The "Web References" tab has many features for slicing and dicing the view, but my favorite is its ability to drag Web references and drop then in the process editor canvas.

Just below the process editor canvas in the center is the Outline tab. This view displays all the major components of the current BPEL process. To the right is the Properties view that displays names and values of properties of the currently selected resource. The process editor, outline and properties views are all selection-synchronized. That is, select a component in the outline view and the component is also selected in the process editor and its properties are displayed.

Another nice feature is the "Problems" tab at the bottom of the display. The ActiveBPEL Designer generates a list for all the incomplete or invalid BPEL constructs in a process. The messages are informative and useful when completing a process.

Tutorial
To exercise the designer, I walked through the tutorial included in the 446-page ActiveBPEL Designer User's Guide provided by Active Endpoints. The tutorial was thorough, covering not only the basics, but providing steps for fault handling, compensation, simulation, deployment, and debugging. The designer was very responsive and the user interaction required to build a process was well thought out.

One of the nice features in Designer is the ability to store groups of activities to the palette for later reuse. This provides a simple tool to shortcut repetitive work.

Testing
The features for testing and simulating a process execution are simple but very useful. The ActiveBPEL Designer lets the user enter sample data in the Web References view for all messages defined in the process. Files containing test data can also be used. During a simulation run, this test data is fired at appropriate points in the process.

The designer tool comes with the ActiveBPEL engine embedded for simulation and debugging. During a simulation, process execution can be suspended or resumed and process variables can be inspected and modified. Designer allows a user to alter sample data values, expressions, correlation property values, and the partner link addresses of an executing BPEL process.

Remote debugging of a process running on the server is fully supported. In remote debugging, one of the options available is to automatically suspend the process when it's first invoked from the Designer. This lets the user easily step through a process executing on the server. There are far too many knobs and levers in the remote debugging feature to go into in this review. Suffice it to say that it seems the team at Active Endpoints has probably experienced and provided support for most of the remote debugging scenarios you're likely to encounter.

Custom Functions
For those that like to tinker under the hood, Active Endpoints provides two support mechanisms for custom functions in a BPEL process. First, the Jaxen (java XPath engine) FunctionContext interface is supported. This interface provides an API for XPath expression evaluation.

The preferred interface is the ActiveBPEL server Java framework. This framework supports custom function extensions as a set of Java Interfaces and classes. A developer basically creates a custom function context and custom function using the interfaces from the framework. Then he packages the code as a jar file and deploys it to the ActiveBPEL designer for simulation and the ActiveBPEL server for execution.

A nice feature is that custom functions can be made available in the expression and query builders and are supported under simulation just like any other built-in function.

Licensing
In this era of Open Source and its hybrid business models, Active Endpoints has crafted an interesting licensing model that is developer-friendly.

First the ActiveBPEL engine core is an Open Source product and has been since July 2004. The engine isn't a feature-crippled version but a fully functional BPEL engine that can run all the BPEL processes created by the ActiveBPEL Designer tool. Second, although not an Open Source product, the designer tool is freely downloadable from the Active Endpoint's Web site. So, for the cost of a little bandwidth and your patience during a download, you can have a fully functional BPEL-enabled development and runtime environment. Pretty slick, huh?

"But how do they pay the bills?" you may ask. Well, aside from the standard services and support fees, Active Endpoints has created an enterprise version of its BPEL engine with a few key high-end features. Process versioning is one key feature but most importantly it's added all the hooks, bells and whistles to ensure that the engine is integrated tightly with today's top application server platforms. High availability, clustering and seamless platform systems management integration are the money features. A process can also be set to suspend on an uncaught fault and breakpoints can be set at appropriate points in the process.For large enterprises that run mission-critical processes, the enterprise version of ActiveBPEL engine is a must. The cost of the enterprise product varies based on the deployment platform and ranges from a low-end Tomcat-enabled version to a J2EE-enabled version that can run on a mainframe.

Support
Active Endpoints offers a few support options. First, for Open Source users, forum and mailing list-based support is provided. I registered and logged onto the free forum to check it out. There seemed to be plenty of activity and strong participation from the user community as well as Active Endpoints people.

There's also a premium support forum for users with a valid product serial number. For those enterprises with higher support demands, incident-based support can be purchased.

Active Endpoints has an excellent Web-enabled bug tracking system that lets customers search and filter the entire bug database. The layout is clear and easy-to-use and a good self-service support feature.

Conclusion
Active Endpoints has created an excellent BPEL design tool and execution engine that is freely downloadable, well documented and has good community support. There's virtually no cost of entry and enterprise reliability features can be purchased for mission-critical applications.

For any of our readers out there who are looking at BPEL solutions, Active Endpoints' products should definitely be at the top of their list.

Company Info
Active Endpoints, Inc.
Three Enterprise Drive
Shelton, CT 06484

Web: http://www.active-endpoints.com/
E-mail: info@active-endpoints.com

Licensing Information
ActiveBPEL Designer: Free
ActiveBPEL Engine (Open Source): Free
ActiveBPEL Enterprise:$7.5k-$30k per CPU based on the deployment platform

Testing Environment
OS: Windows XP Professional (Service Pack 2)
Hardware: Intel Pentium M Processor (1300MHz) - 1.29GHz with 1GB RAM