lams-github

Methods which calculate LearnerProgress dates and status use ugly

instanceof constructs. There seem to be no good alternatives, though.

LearnerProgressArchive can inherit from LearnerProgress and we use

table-per-subclass Hibernate strategy. But then queries for

LearnerProgress would fetch also LearnerProgressArchive entities unless

in each HQL query we put "WHERE lp.class = LearnerProgress". It is easy

to forget plus generic methods like findAll() will not work well anyway.

LearnerProgress and LearnerProgressArchive can extend a new

AbstractLearnerProgress and we use table-per-concrete-class Hibernate

strategy. Same with CompletedActivityProgress and

CompletedActivityProgressArchive. But then

AbstractLearnerProgress.completedActivities will not let use both of

them due to lack of polymorphism in collections. Neither

Map<Activty, AbstractCompletedActivityProgress>

nor

Map<Activity, ? extends AbstractCompletedActivityProgress>

will not work. And this collection is the main reason why to do

inheritance in the first place.

Looking how the above solutions add complexity and little gain, these

few methods with instanceof seem to be a fine trade off. Show less