spiff-arena/docs/Building_Diagrams/sub-processes_and_call_activities.md

Sub-Processes and Call Activities

Sub-processes and call activities are both useful for simplifying and organizing complex workflows within larger processes. They have distinct purposes and are used in different scenarios.

Reasons to use a Sub-Process or Call Activity:

• Consolidating tasks with common features or forming a distinct functionality, such as a Notification Gateway that constructs and sends notifications like emails.

• Grouping tasks where a boundary event can efficiently be applied to the entire group, avoiding the need to assign conditions or timers individually to each task.

Call Process

A call process encapsulates part of a workflow and can be reused across multiple processes. It functions as a stand-alone process that can be called into action by other processes. Using a call process eliminates redundancy and ensures consistent execution of process steps.

When to use a Call Process:

• Reusability: When a set of activities is reused in multiple main processes, defining it as a call process allows for easy reuse by calling the process.

• Reducing Complexity: Breaking down a complex main process into smaller, manageable call processes can make it easier to understand and maintain.

• Version Control: If a process may undergo changes over time but is used in multiple places, defining it as a call process allows changes to be made in one place and propagated to all instances where the process is used.

• Delegation: When different individuals or teams are responsible for executing tasks within a process, a call activity can be assigned to the most appropriate person or team.

• Access Control: If a specific segment of a process should not be available to every user, converting it into a call process helps establish access control. More information about this can be found in the Admin and Permission section.

Sub-Processes

Sub-processes are typically used within a single process and are not reusable across multiple processes like call activities. When the conditions for reusability are not necessary, a sub-process is usually the preferred option.

When to use a Sub-Process:

• Consolidating Similar Functionalities: When a group of tasks are closely related and work well together, but do not need to be used or replicated elsewhere in other processes.

• Not Requiring a Call Activity: When tasks do not meet the conditions required for a call activity, a sub-process can achieve the same goal.

• Applying Conditions or Events: When specific conditions or events, such as a timer event, need to be applied to a set of tasks that do not collectively form a reusable workflow that can be called as a separate process.