What is XML Process Definition Language (XPDL)

xpdl graph

The XML Process Definition Language (XPDL) can be defined as a standardized format by the WfMC (Workflow Management Coalition) in order for the business process definitions to be switched between many workflow products, management suites and modeling tools. With help of XPDL you can define XML schematics to specify specific parts of the business process. With XPDL you can exchange both semantics and graphics of the business process. At the moment, XPDL is the best exchanging file format of BPMN diagrams and it has been specifically created for storage of everything regarding BPMN diagram. XPDL has many elements that contain graphical information and other aspects relating running certain process.

            The main target of XPDL, besides storing, is to exchange the process diagram. It allows one tool for modeling the process diagram and other one for reading and editing the diagram. Unlike BPEL, XPDL is not executable programming languages, but a format that represents the graphics of the process definition.

History of XPDL

            So-called Workflow Management Coalition, started working on defining the Workflow Reference Model back in the early 90s of the past century. It found and pointed 5 main interfaces which every workflow management system needs to have. Interface 1 is for defining the process of business. It has two aspects – an interface for transferring process definition to and from workflow management system and a process definition expression language. In 1998 the process definition expression language was named Workflow Process Definition Language or WPDL. This contained al main conspectus needed for supporting workflow automation.

            The first quality standards which were based on XML appeared in year 1998.The Workflow Management Coalition Working Group 1 created XML Process Definition Language (XPDL). It had some improved concepts which made things a bit easier. The XPDL is also known as XPDL 1.0 and was ratified by Workflow Management Coalition in year 2002. After that it was implemented by many BPM products and workflow products to exchange process definitions. At that time, XPDL was the only language for interchange of process design.

            In the following years, Workflow Management Coalition continued updating and improving the process definition interchange language. The third revision of process definition expression language was called XPDL and was ratified by Workflow Management Coalition in year 2005. Year 2008 was the year when Workflow Management Coalition ratified XPDL 2.1, which was fourth revision including extension for handling BPMN 1.1 constructs. Finally, in 2012, XPDL 2.2 was ratified as fifth revision, which was improved and included support for modeling extensions that have been added to BPMN 2.0.

            This was the main information about what XML Process Definition Language is and what it involves. It is a bit complex matter that many people do not have good knowledge of. Hopefully this info has cleared some of the unknown things, but you are free to dig deeper for more information about this matter. Get yourself properly informed about all details regarding XML Process Definition Language and put that in good use.