Correlation

When executing a business process instance, one or many communications occur with partners that are part of the process. In some cases, correlated conversations that involve more than two entities or leverage a lightweight transport infrastructure with a correlation token exist inside the application data moving between parties. Thus, in many instances, it is necessary to provide additional application-level mechanisms that match message and conversation inside the business process instances.

To this end, BPEL4WS addresses correlation scenarios, providing a declarative mechanism that specifies correlated groups of operations inside an instance of a service, and a set of correlation tokens can be defined as a set of properties shared by all messages inside a correlated group. This is known as a correlation set, which is instantiated inside the scope of an instance of a business process.