The NetBpm Users Manual

NetBpm is a .Net enterprise application that implements a uniquely flexible and extensible workflow management system (WFMS). The core functionality of NetBpm comprises an engine that maintains the state of the fully customisable processes. NetBpm as a system can be viewed as the combination of several components, each of these components has an well-defined interface.

In its essence, NetBpm solves the following problem : How to combine normal programming logic with results that are produced by other systems or people which cannot be obtained in real-time ? Execution of a business process continiously switches between execution and waiting on input from a 3rd party. The NetBpm engine keeps track of each party it is waiting for and what activities those parties should be doing. When such an external party supplies the results to the NetBpm engine, it continues to execute the process definition.

The first component allows users to load descriptions of business processes into the application using the NetBpm Process Definition Language (nPdl). nPdl is an simple, yet powerful XML, human-readable defintion language. In nPdl one business process is contained within one process archive (a ziped file with all process information). Process archives are created and then deployed (read loaded) into the NetBpm application. Once a process archive is deployed, NetBpm provides a second interface to clients to perform an activity (read step) of the process. When an activity is performed NetBpm will calculate the next state of the process and assign new actors to activities that have to be performed. Important events occurs behind the scenes during these calculations. NetBpm provides hooks to execute actions in reponse to these events. Also, these actions can access the process attributes as well as access all systems in the organisation because they are executed within a container. These actions provide the link between Business Process Management (BPM) and Enterprise Application Integration (EAI).

The information contained in a process archive is called a process definition

Process name and versions

Processes are distinct by name, meaning that the name of a process determines whether two process definitions are equal. In a process archive it is not possible to specify a version. When a process definition is deployed, NetBpm will check for older versions of the same process definition. NetBpm will assign as a version number one more then the highest version number it finds for that process definition.

Process execution and versions

When collecting the list of process definitions from the execution component, only one version of every process definition will be returned (the one with the highest version number, of course). This enables to start process definitions always in the latest version.

If a new version of a process definition is uploaded into NetBpm, all the process instances that are running in the older versions, keep on executing in their old process definitions.

Delegation classes and versioning

Another aspect of versioning is the versioning of the delegation classes. The approach is straightforward : classes are not shared between subsequent versions of process definitions. This means that a process execution is only able to see the classes of its own process definition.