This activity enables you to define a collection of activities to perform in sequential order. For example, you may want the following activities performed in a specific order:

• A customer request is received in a receive activity.

• The request is processed inside a flow activity that enables concurrent behavior.

• A reply message with the final approval status of the request is sent back to the customer in a reply activity.

A sequence activity makes the assumption that the request can be processed in a reasonable amount of time, justifying the requirement that the invoker wait for a synchronous response (because this service is offered as a request-response operation).

When this assumption cannot be made, it is better to define the customer interaction as a pair of asynchronous message exchanges.

When you double-click the Sequence icon, the activity area shown in Figure A-39 appears. Drag and define appropriate activities inside the sequence activity.

For more information about the sequence activity, see the following:

• Introduction to Interaction Patterns in a BPEL Process

• Creating a Parallel Flow