BPEL4People

Contributors: Active Endpoints, Adobe, BEA Systems, IBM, Oracle, SAP AG

Originally published on Arch2Arch June 2007

Abstract

WS-BPEL focuses on business processes that orchestrate Web service interactions. Business processes are often comprised of many activities requiring the participation of people to perform tasks, review or approve steps, and enter data. Credit approval is one example. These human interactions are now addressed in the new specifications.

BPEL4People is comprised of two specifications including:

WS-BPEL Extension for People which layers features on top of WS-BPEL to describe human tasks as activities that may be incorporated as first class components in WS-BPEL process definitions.
Web Services Human Task introduces the definition of stand-alone human tasks, including their properties, behavior and operations used to manipulate them. Capabilities provided by Web Services Human Task may be utilized by Web services-based applications beyond WS-BPEL processes.

Introduction

The BPEL4People specification introduces an extension to BPEL in order to support a broad range of scenarios that involve people within business processes.

The BPEL specification focuses on business processes the activities of which are assumed to be interactions with Web services, without any further prerequisite behavior. But the spectrum of activities that make up general purpose business processes is much broader. People often participate in the execution of business processes introducing new aspects such as interaction between the process and user interface, and taking into account human behavior. This specification introduces a set of elements which extend the standard BPEL elements and enable the modeling of human interactions, which may range from simple approvals to complex scenarios such as separation of duties, and interactions involving ad-hoc data.

The specification introduces the people activity as a new type of basic activity which enables the specification of human interaction in processes in a more direct way. The implementation of a people activity could be an inline task or a standalone human task defined in the WS-HumanTask specification [WS-HumanTask]. The syntax and state diagram of the people activity, and the coordination protocol that allows interacting with human tasks in a more integrated way is described. The specification also introduces XPath extension functions needed to access the process context.

The goal of this specification is to enable portability and interoperability:

Portability - The ability to take design-time artifacts created in one vendor's environment and use them in another vendor's environment.
Interoperability - The capability for multiple components (process infrastructure, task infrastructures and task list clients) to interact using welldefined messages and protocols. This enables combining components from different vendors allowing seamless execution.

Download the Specification

This specification is being made available on an RF basis (as detailed in the copyright notice of the specification); therefore, BEA does not require an implementation license. If you prefer, however, you may request a license from BEA to implement the specification.

Use the following links to download the BPEL4People and WS-HumanTask specifications.