Apache ODE ("Orchestation Director Engine") aims to produce an implementation of the WS-BPEL 2.0 standard suitable for embedding in a generic runtime context. ODE recently graduated from incubation to a fully-fledged top-level project and had its first release since leaving incubation. This note provides a nickel tour and teaser for ODE along with some BPEL concepts in the form of deploying and executing a simple process.

The ODE philosophy on BPEL is that it is a language for describing how to implement a set of message-based communication capabilities in terms of state manipulation and messages exchanged with external services. Other than in this sentence and in the preceding paragraph, the word "business" will not appear, and there will be no talk of alignment with IT or other silliness — ODE is guilt-free (and gilt-free) technology like a web server or a database; what you do with it is up to you. No GUI, IDE, ESB, or other TLA (other than a little XML) is required. Implementing an orchestration engine is a tantalizing but daunting task, and ODE encapsulates the details of concurrency, durable continuation (also called dehydration/rehydration), reliability, and recovery. Perhaps most importantly, ODE is delivered as a component rather than a framework in the hope that it can serve as a baseline for developers looking to add orchestration functionality to their systems.

Where it's needed for clarity, I'll call out a specific version of BPEL, e.g., BPEL4WS 1.1, but otherwise, "BPEL" refers to WS-BPEL 2.0.

See the complete article from Paul Brown on InfoQ.