Dynamic Parallel Flow

In Chapter 3 we became familiar with the <flow> activity, which enables to start several parallel activities. In our Travel process example we used <flow> activity to start two parallel sequences that acquired plane ticket offers from American and Delta Airline web services. As the operation invocations for the ticket offers were asynchronous, we had to use <receive> activities to wait for the callbacks.

The problem with the <flow> activity is that we need to know in advance how many parallel activities are required. The number of parallel activities is specified by the BPEL code. In several real-world use cases this is limiting, because the number of required parallel branches can depend on the information stored in a variable or received from the partner web service. In such cases, the <flow> activity is inadequate.

Oracle BPEL Process Manager therefore provides <flowN> activity, which can create multiple parallel activities at...