Domain Model

This chapter summarizes principal entities; authoritative behavioral details live in the referenced chapters.

Registration

Component	Type	Description
Registration::Campaign	ActiveRecord	Time‑bounded process (modes: FCFS, preference_based)
Registration::Item	ActiveRecord	Wrapper exposing a registerable option under a campaign
Registration::UserRegistration	ActiveRecord	(user, item) intent + status (pending/confirmed/rejected) + optional preference_rank
Registration::Policy	ActiveRecord	Ordered eligibility rule (student_performance, institutional_email, prerequisite_campaign, custom_script)
Registration::Campaignable	Concern	Enables a model to host registration campaigns
Registration::Registerable	Concern	Enables a model to be an option within a campaign
Registration::PolicyEngine	Service	Executes ordered active policies; short‑circuits on first failure
Registration::AllocationMaterializer	Service	Applies confirmed allocations → registerable.materialize_allocation!

Rosters

Component	Type	Description
Roster::Rosterable	Concern	Unified roster API (`roster_user_ids`, `replace_roster!`, etc.)
Roster::MaintenanceService	Service	Post-allocation admin (move/add/remove) with capacity enforcement

Assessments & Grading

Component	Type	Description
Assessment::Assessment	ActiveRecord	Gradebook container for graded work (assignment, exam, talk, achievement)
Assessment::Participation	ActiveRecord	Per-user totals, grade, status, submission timestamps
Assessment::Task	ActiveRecord	Per-assessment graded component (only if requires_points)
Assessment::TaskPoint	ActiveRecord	Per (participation, task) points + grader + submission link
Assessment::Assessable	Concern	Enables a model to be linked to an Assessment::Assessment
Assessment::Pointable	Concern	Extends Assessable to enable per-task point tracking
Assessment::Gradable	Concern	Extends Assessable to enable final grade recording
Assessment::SubmissionGrader	Service	Submission-centered fan-out to TaskPoints for team grading
Submission	ActiveRecord	Team-capable artifact optionally linked to a task

Student Performance & Certification

Component	Type	Description
StudentPerformance::Record	ActiveRecord	Materialized factual performance data per (lecture, user): points_total, achievements_met
StudentPerformance::Rule	ActiveRecord	Configuration for eligibility criteria (min_points, required_achievements, assessment_types)
StudentPerformance::Certification	ActiveRecord	Teacher's eligibility decision per (lecture, user) with status (passed/failed/pending)
Achievement	ActiveRecord	Assessable type for qualitative accomplishments (e.g., blackboard presentations) with Assessment infrastructure
StudentPerformance::Service	Service	Computes and upserts Records from coursework points and achievements
StudentPerformance::Evaluator	Service	Generates eligibility proposals by evaluating Records against Rules
Registration::Policy (kind: student_performance)	Integration	Checks Certification.status during exam registration (no runtime recomputation)

Grading Schemes

Component	Type	Description
GradeScheme::Scheme	ActiveRecord	Versioned configuration for converting assessment points to final grades
GradeScheme::Applier	Service	Applies scheme to compute and persist final grades for all participations

Allocation Algorithm

Component	Type	Description
Registration::AllocationService	Service	Strategy dispatcher using pluggable solvers (Min-Cost Flow, future CP-SAT)
Registration::Solvers::MinCostFlow	Service	OR-Tools SimpleMinCostFlow implementation for bipartite preference allocation
Registration::Solvers::CpSat	Service	Future CP-SAT solver for advanced constraints (fairness, mutual exclusion, quotas)

These are the "glue" entities that connect the core domain models (User, Lecture, Tutorial, etc.) to the systems above. They enable domain models to participate in registration, assessment, and eligibility tracking.

Core Domain Models:

User - Students, teachers, tutors who participate in the system
Lecture - A course offering (e.g., "Linear Algebra WS 2024/25")
Tutorial - A tutorial group within a lecture
Talk - A student presentation or seminar talk
Assignment - A homework assignment
Exam - An exam assessment

How they link to the systems:

Domain Model	Links To	Via	Purpose
Lecture	Registration	`Registration::Campaignable` concern	Host exam registration campaigns
Tutorial	Registration	`Registration::Registerable` concern	Become a registerable option in tutorial allocation
Exam	Registration	`Registration::Campaignable` concern	Host exam registration campaigns
Assignment	Assessment	`Assessment::Pointable` concern	Track per-task points for homework
Exam	Assessment	`Assessment::Gradable` concern	Record final exam grades
Talk	Assessment	`Assessment::Gradable` concern	Grade student presentations
User	All Systems	Direct associations	Student participates in registrations, assessments, eligibility
Lecture	Exam Eligibility	Direct association	Scope eligibility records to specific lecture

Example Flows:

Tutorial Registration: Lecture (campaignable) → creates Registration::Campaign → contains Registration::Item wrapping Tutorial (registerable) → students submit Registration::UserRegistration
Exam Registration: Lecture (campaignable) → creates Registration::Campaign → contains Registration::Item wrapping Exam (registerable) → students submit Registration::UserRegistration → policies check eligibility
Homework Grading: Assignment (pointable) → linked to Assessment::Assessment → contains Assessment::Task → tutors record Assessment::TaskPoint → aggregated into Assessment::Participation
Exam Eligibility: Lecture → students complete Assignment assessments → StudentPerformance::Service aggregates points into StudentPerformance::Record → StudentPerformance::Evaluator generates proposals → teacher creates StudentPerformance::Certification → Registration::Policy (kind: student_performance) checks Certification.status when student attempts Exam registration via the lecture's exam campaign

High-Level ERD (Simplified)

erDiagram
    USER ||--o{ REGISTRATION_USER_REGISTRATION : submits
    REGISTRATION_CAMPAIGN ||--o{ REGISTRATION_ITEM : has
    REGISTRATION_ITEM ||--o{ REGISTRATION_USER_REGISTRATION : options
    REGISTRATION_CAMPAIGN ||--o{ REGISTRATION_POLICY : guards
    REGISTRATION_ITEM }o--|| REGISTERABLE : polymorphic
    ASSESSMENT ||--o{ ASSESSMENT_PARTICIPATION : has
    ASSESSMENT ||--o{ TASK : has
    TASK ||--o{ TASK_POINT : points
    ASSESSMENT_PARTICIPATION ||--o{ TASK_POINT : aggregates
    SUBMISSION ||--o{ TASK_POINT : optional
    USER ||--o{ ASSESSMENT_PARTICIPATION : participates
    LECTURE_PERFORMANCE_RECORD }o--|| USER : "factual data"
    LECTURE_PERFORMANCE_RECORD }o--|| LECTURE : "scoped to"
    LECTURE_PERFORMANCE_CERTIFICATION }o--|| USER : "decision for"
    LECTURE_PERFORMANCE_CERTIFICATION }o--|| LECTURE : "scoped to"
    LECTURE_PERFORMANCE_CERTIFICATION }o--|| LECTURE_PERFORMANCE_RECORD : "based on (optional)"
    ACHIEVEMENT }o--|| USER : "accomplished by"
    ACHIEVEMENT }o--|| LECTURE : "belongs to"
    GRADE_SCHEME_SCHEME ||--|| ASSESSMENT : "applies to"

See details:

MaMpf Architecture

Domain Model

Registration

Rosters

Assessments & Grading

Student Performance & Certification

Grading Schemes

Allocation Algorithm

Linking Concepts

High-Level ERD (Simplified)

Keyboard shortcuts

MaMpf Architecture