BPEL Business Process Engineering Language A technology used to build programs in SOA architecture

Business processes

Business Process ProcessProcess is a sequence of steps that is: – initiated by an event, –transforms its inputs (in many repsects) and – produces a specified output. business processA business process is a set of logically related tasks performed to achieve a well-defined business outcome. –Defines the results to be achieved, the context of the activities, the relationships between the activities & the interactions with other processes and resources

Process-oriented workflows

Web Services & Business Processes Building composite services by combining existing elementary or complex services –requires coordinating the flow of control and information between the component services. Business logic can be seen as the ingredient that sequences, coordinates, and manages interactions among web services. Techniques for Web services composability draw heavily on business process modelling and workflow processing languages.

Flow Model How to combine? Order execution Decision points Passing data

Transition conditions

Service Composition

WS orchestration vs. choreography Orchestration describes how WSs can interact at the message level, from the perspective and under control of a single endpoint (single party). Choreography –is associated with the public message exchanges, rules of interaction & agreements that occur between multiple business process endpoints. –tracks the sequence of messages that may involve multiple parties & multiple sources, & described from the perspectives of all parties (common view).

BPEL an orchestration language models business process collaboration ( s), models the execution control of business processes, separates abstract definition from concrete binding, supports fault handling & compensation, supports service composability (structured activities can be nested and combined arbitrarily), supports context ( mechanism), spawns off & synchronizes processes ( & activities), supports event-handling.

BPEL structure

BPEL abstract & executable processes