Summary

In a complex application decisions have to be made whether a person is allowed to perform a certain action. This is frequently encountered in Dynamic Case Management applications where a user is only allowed to perform a subset of tasks. You may also encounter it in applications without process engine, where the end user is not allowed to see certain information based on some criteria.

As the user permission example does not concern the core business rules of a company, but a way of structuring the work of its employees, is the Application Layer the appropriate location for this scenario (arrow 5). External systems may use the same logic for deriving user permissions (arrow 4).

Context

For the user permission example the following categories are important.

Problem

A good example can be found in a DCM application for mortgage applications. Based on the current application the system has to decide whether the Junior Mid-Office employee is allowed to make the approval decision, or if a more senior role is needed. The stakeholders may decide that any property with a value under half a million can be done by junior employees, while anything above has to be done by a senior employee. Furthermore the user should not have performed previous tasks for the application, to adhere to the four-eyes principle.

The problem of this case is not how to create such logic, as that is perfectly doable using Blueriq's rule engine. The problem lies in the maintainability of the application. Logic for user permissions is different to other logic (e.g., calculating a mortgage amount) and mixing them may decrease the maintainability. User permissions concerns the manner in which knowledge workers interact with the system, not with the domain at hand.

Solution

The solution direction that are interesting to this problem concern the separation of the logic for the user permissions and the logic for the application itself. The following patterns are relevant in this example.

Implementation characteristics	Property	Pattern 2: Webservice	Pattern 5: Function	Pattern 6: External rule
Decision management	Implicit vs. Explicit call
	User set vs. System set
	Implicit calls
Implementation property	Autonomy
	Maintainability
	Re-usability
	Out of the box