WS-Flow Language
WSFL is short for Web Services Flow Language . WSFL is part of the so-called WS- * specifications as an industrial standard of the World Wide Web Consortium W3C.
The Web Services Flow Language (WSFL) is one of IBM developed XML - language for describing Web services business process . WSFL uses XML to define a model of a directed graph of activities connected by control flows and data flows , which can be processed in a workflow engine .
WSFL's ideas were incorporated into WS-BPEL , among others .
The Web Services Flow Language supports two types of compositions and choreographies:
- Flow models describe the business processes
- Global models describe all of the partner interactions.
Flow models
The performance unit in WSFL is an activity and is represented by means of nodes in a linked diagram, the dataLink and controlLink represent the data flow and the control flow between these activities. A DataLink indicates that its source activity sends data as part of the context of the process instance to the flow Engine forwards, which in turn must pass on (part of) this data to the target activity of the DataLink. Data always flows through controlLinks. However, the controlLink path does not have to be direct and can span multiple activities. If required, the dataLink enables the specification of an assignment between a source and a target document.
There is at most one ControlLink between two activities and the model must be acyclic so that loops within the control flow are prohibited. However, the model supports recurring activities using an exit condition mechanism that runs until the exit condition becomes true. The control flow model supports forks (activities with more than one outbound transition) and joins (activities with more than one inbound transition). Activities that have no inbound transitions are known as start activities, similar to activities without outbound transitions as end activities. When a flow model is instantiated, all of its startup activities are identified and scheduled to run.
Global models
The global model offers the possibility to model interactions between business partners. It should be noted, however, that a global model is only an assignment between inputs and outputs. In contrast to EbXML BPSS, business semantics such as rejection, service quality, legally binding, guaranteed delivery on the application level cannot be specified by a global model. WSFL collaborations are a little more useful than XLANG contracts because they allow mapping with bidirectional services, but they are still a long way from ebXML BPSS.
Individual evidence
- ^ Web Services Flow Language (WSFL). February 4, 2002, accessed October 26, 2018 .
- ↑ a b ebpml: WSFL. Retrieved October 26, 2018 .