Starting an Integration Process Based on Multiple Interfaces

  • by Dr. Volker Stiehl, Professor, Ingolstadt Technical University of Applied Sciences
  • May 10, 2013
Learn how to benefit from SAP NetWeaver Process Orchestration even for integration processes requiring different messages for process instantiation. Although SAP NetWeaver Business Process Management, which is ultimately responsible for the process implementation, doesn’t allow the definition of several start events, you can circumvent this restriction by defining a super interface comprising all the interfaces on which the process start depends. Reusing this idea allows you to model similar scenarios that also require multiple interfaces to be initiated.
Key Concept

With SAP NetWeaver Process Orchestration you can model executable business process model and notation (BPMN)-based processes that can contain start and intermediate message events depending on exactly the same interface. The process engine responsible for executing the process model decides dynamically during runtime whether to start a new process instance for an incoming message or to forward the message to an already-running instance. This behavior is called Conditional Start in SAP nomenclature and is a prerequisite for implementing enterprise integration patterns (EIP) such as the aggregator pattern.

For building stateful integration-centric processes handling the reliable message transfer between systems and applications, developers can use SAP NetWeaver Business Process Management (SAP NetWeaver BPM) in combination with SAP NetWeaver Process Integration (SAP NetWeaver PI). They are both part of SAP NetWeaver Process Orchestration (SAP NetWeaver PO), SAP’s new middleware package.

SAP NetWeaver BPM takes over the role of a state machine on the pure Java stack for those cases. Formerly, on the SAP NetWeaver PI double stack (e.g., running on both Java and ABAP), this role was covered by cross-component Business Process Management (ccBPM). As SAP is moving strategically to the Java stack for its middleware solution, organizations are now starting to migrate their existing stateful integration scenarios to SAP NetWeaver PO. Obviously, the question is raised whether all scenarios modeled using ccBPM can be migrated to SAP NetWeaver PO.

In my previous articles (“Bringing ccBPM-based Integration Processes to SAP NetWeaver PO: Why Automation Doesn't Work,” “Properly Convert Existing ccBPM-based Integration Processes to SAP NetWeaver Process Orchestration,” and “Remodeling ccBPM Processes Using SAP NetWeaver PO: How to Distribute Work between BPM and PI”) I explained how a migration of existing ccBPM-based integration processes looks. In this installment I’ll address another typical use case that often occurs in integration scenarios: the collection and aggregation of data belonging to different interfaces (representing different messages) when it is not known beforehand which message comes in first. Hence, the process must be able to start as soon as one of the respective messages arrives. Let’s see how this challenge can be solved using SAP NetWeaver PO.

Stateless integration processes differ from stateful integration processes in that they cover only normal message handling procedures such as receiver determination, interface determination, and mappings. They describe the message handling within the enterprise service bus (ESB). Once the message has left the ESB, the process is finished. The tool of choice for stateless processes is the PI Designer. Stateful processes on the other hand store or persist data while they are executed. The perfect example is the Aggregator pattern, which collects several messages and stores them within the process until the end condition is reached. The stored messages represent the state. Once the end condition is fulfilled, the stateful process sends out the collected message in a bundle to the receiver. The tool of choice for modeling stateful messages is SAP NetWeaver BPM. Typically you correlate several messages in a stateful process in contrast to stateless processes, which only care exactly one message.


Dr. Volker Stiehl

Prof. Dr. Volker Stiehl studied computer science at the Friedrich-Alexander-University of Erlangen-Nuremberg. After 12 years as a developer and senior system architect at Siemens, he joined SAP in 2004. As chief product expert, Volker was responsible for the success of the products SAP Process Orchestration, SAP Process Integration, and SAP HANA Cloud Integration (now SAP HANA Cloud Platform, integration service). He left SAP in 2016 and accepted a position as professor at the Ingolstadt Technical University of Applied Sciences where he is currently teaching business information systems. In September 2011, Volker received his Ph.D. degree from the University of Technology Darmstadt. His thesis was on the systematic design and implementation of applications using BPMN. Volker is also the author of Process-Driven Applications with BPMN as well as the co-author of SAP HANA Cloud Integration and a regular speaker at various national and international conferences.

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