BPEL“ Fixes”WsDL XWSDL: unordered set of operations Operations are message exchanges x Need rules for ordering
BPEL “Fixes” WSDL WSDL: unordered set of operations – Operations are message exchanges Need rules for ordering
BPEL Is a web service Sequencing Language 区 Process defines“ conversation"flow chart Conversation consists of only WSDL-described message exchanges Process instance is a particular conversation following the chart EXecution systems can support multiple concurrent conversations
BPEL Is a Web Service Sequencing Language Process defines “conversation” flow chart – Conversation consists of only WSDL-described message exchanges. Process instance is a particular conversation following the chart – Execution systems can support multiple concurrent conversations
BPEL Is a Graph-oriented Language k The XML-based nature of BPEL processes enables the editing of process logic using visual design and modeling tools 区 Activity Nodes Represent message exchanges, internal operations, decision points 区Arcs Order of execution Constraints on concurrent processing k Directed acyclic graph Much like java k Separate error compensation handling
BPEL Is a Graph-oriented Language The XML-based nature of BPEL processes enables the editing of process logic using visual design and modeling tools Activity Nodes – Represent message exchanges, internal operations, decision points Arcs – Order of execution – Constraints on concurrent processing Directed acyclic graph – Much like Java Separate error & compensation handling
Example e@ reply More assign <assign> prepareTaskRe Copy Rules Add invoke InitiateTask creator (Review) assignee duration template on Task onCancelTask (Review) Source: Collaxa BPEL Designer
Example Source: Collaxa BPEL Designer
BPEL is a web Service Composition Language x Consumes services(invoke) x Creates services(receive/reply) k Aggregates fine-grained services Creates coarser-grained service
BPEL is a Web Service Composition Language Consumes services (invoke) Creates services (receive/reply) Aggregates fine-grained services Creates coarser-grained service