| Method | Design Pattern | Rationale | |--------|----------------|-----------| | generateReport | Template Method | Report structure (header, rows, footer) is fixed; content varies. | | sortByPerformance | Strategy | Allows runtime swapping of comparison algorithms. | | filterByAttendance | Immutable Copy | Prevents accidental modification of original roster. | | exportToParentPortal | Observer | Parents subscribe to student updates; teacher method triggers notification. |
| Method Signature | Description | |------------------|-------------| | generateReport(ClassList c, DateRange d) | Produces attendance/grade summary | | sortByPerformance(ClassList c, Comparator<Student> comp) | Orders students by grades | | filterByAttendance(ClassList c, int minPercent) | Returns students meeting attendance threshold | | exportToParentPortal(ClassList c, Set<Parent> contacts) | Securely shares data with guardians | 7.2.9 Teacher Class List Methods
[2] E. Gamma, R. Helm, R. Johnson, and J. Vlissides, Design Patterns: Elements of Reusable Object-Oriented Software . Addison-Wesley, 1995. | Method | Design Pattern | Rationale |
function generateReport(c, d): report = new Report("Class Report for " + d) for student in c: summary = new StudentSummary(student.name) summary.grades = fetchGrades(student, d) summary.attendance = fetchAttendance(student, d) report.addRow(summary) return report.toPDF() O(n * m) where n = students, m = grade records per student. 3.2.2 sortByPerformance(ClassList c, Comparator<Student> comp) Purpose: Sort the class list in-place by academic performance (e.g., descending grade average). Uses the provided comparator to allow alternate metrics (e.g., improvement rate). | | exportToParentPortal | Observer | Parents subscribe
function sortByPerformance(c, comp): // In-place merge sort for stability and O(n log n) worst-case c.students = mergeSort(c.students, comp) c.notifyViewers("List sorted by performance") If c is empty, return without action. If comp is null, use default compareByGradeDesc() . 3.2.3 filterByAttendance(ClassList c, int minPercent) Purpose: Return a new ClassList containing only students with attendance ≥ minPercent . The original list remains unchanged (immutability pattern).
interface PerformanceComparator extends Comparator<Student> {} class GradeComparator implements PerformanceComparator int compare(Student a, Student b) return Double.compare(b.gradeAverage, a.gradeAverage);