Having analyzed your business requirements, you are now in a position to start the implementation of your decision details for your product.
You are likely to re-use some of the calculation results already implemented for your eligibility/entitlement calculations, as some decision details are already part of your eligibility and entitlement logic. Other decision details may require additional calculations to make them suitable for display.
It is recommended that you implement your decision details rule classes in a rule set separate from your eligibility/entitlement rule set(s), but allow your decision details rule classes to depend on your eligibility/entitlement rule classes (but not the other way around).
This approach means that you can evolve your decision details implementation in the future without having to retest your eligibility/entitlement implementation; this can be important since key decision details are merely "view" data to aid the case worker, whereas eligibility/entitlement results may affect more critical business functions such as how much a client is actually paid.
It can be helpful to track the dependencies between your rule sets so that as your product evolves, you have an insight into how changes in one rule set might affect other rule sets that depend on it.
For each product period and display category, you must create:
It is possible that your decision details are calculated in an identical way across product periods, in which case you may be able to re-use one case rule class for many product periods. Your factoring of common calculated eligibility/entitlement results may affect how you must factor your case rule classes for decision details.
You may also create an arbitrary number of rule classes to model the data for display and/or provide intermediate calculations for decision details data. The flexibility of decision details data means that there are no fixed data structures to adhere to (unlike the steps for implementing eligibility/entitlement and key decision factor rules).
The sections below detail a step-by-step path to implement your decision details.