The workflow represents our business process in the SWF. The workflow contains activities and tasks that need to be completed. It will include all of the orchestration logic that connects the activities together, which defines what kind of actions need to be performed in what sequence, or under which circumstances, and in what order. 

For example, we will create a workflow for our ten-step order-processing example from the previous chapter, and each of the ten steps will be represented as a task in the workflow. Each task in the ten steps of the workflow will then either invoke another task or, if it is the last task invoke the completion of the workflow; or send out a failure or timeout notification if the task is not able to complete successfully.

The invocation of other tasks or the decision to mark the process as failed or timed out is carried out by the decider. Each workflow contains deciders that have the ability to perform task scheduling and pass data to the tasks. They also make sure to track events within the workflow while it is in progress. The deciders also close the workflow when completed or upon failure.