XPDL

The XML Process Definition Language ( XPDL ) is within the workflow management, an XML based language for describing business processes, more work processes ( workflow ). Since it is a machine-readable process description, it is also called execution language. The XPDL is being promoted since 1993 by the Workflow Management Coalition ( WfMC ) and standardized. The present since May 2005 Version 2.0 provides full support for the graphical Business Process Model and Notation ( BPMN). XPDL implements the interface 1 in the workflow reference model of the WfMC.

Alternative process execution languages

In addition to the XPDL are the other main process execution language BPEL (Business Process Execution Language ) and the serialization of BPMN (Business Process Modeling Notation or Version 2.0 Business Process Model and Notation) in version 2.0 of the specification. The BPML (Business Process Modeling Language ), which was specified by the Business Process Management Initiative ( BPMI ), lost with the assimilation of BPMI in the OMG in importance and is no longer being developed.

XPDL compared to BPEL

The focus of XPDL is the storable representation of BPMN models. To this end, XPDL is graph- oriented while BPEL follows a block-oriented approach. Therefore, the graph- oriented BPMN models can be better stored in XPDL as in BPEL. Especially loops are bad implemented in BPEL. However, the concept of the edge of a graph can be added via the BPEL extensions. XPDL is designed primarily for the execution of tasks by humans (workflows ), BPEL, however, for the orchestration of computer programs, specifically through web service calls. Therefore, the appropriate role BPEL concepts, particularly the concept of participants ( Participants ) and exporters ( Performers ) are missing. In a limited way this can provide the BPEL4People extension for BPEL. One advantage of BPEL is the handling of error situations, the missing altogether in XPDL.

BPEL and XPDL are not mutually exclusive. So used TIBCO's current BPM suite for modeling an (extended ) version of XPDL, but the diagrams translated for execution in BPEL. ActiveVOS from Active Endpoints BPEL used as modeling and design language, but the XPDL format can be processed. Thus XPDL can also be used as an interchange format between different tools such as graphical modelers, simulation tools and workflow management systems. Since XPDL but in execution is less restrictive than BPEL, proprietary extensions may arise which severely restrict the use of XPDL. With the new serialization of BPMN in its version 2.0, the advantages of XPDL and BPEL are combined.