Monday, September 18, 2006

[Tech] BPEL with User Interaction

BPEL (Business Process Execution Language) is used for service orchestration in Service Oriented Architectures. The current standard of BPEL is designed to automate business processes based on Web Services. However traditional business processes often requires human interactions which is currently not supported by the BPEL standard.

For this purpose, IBM and SAP developed BPEL4People. This extension is defined in a way that is layered on top of the BPEL language so that its features can be composed with the BPEL core features whenever needed. The most important new constructs in this extension are:

  • Generic Human Roles define what a person/group can do in a specific process activity.
  • People Links are used to represent the different groups of people who participate in the execution of the process (e.g. link to LDAP)
  • People activity is a basic activity, which is not implemented by a piece of software, but realized by an action performed by a human being (e.g display an User Interface where the user can do something).
To derive benefit from BPEL4People a BPEL engine must process people activities differently from activities invoking Web Services. This paper (IBM and SAP) gives an detailed overview of BPEL4People.

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