1. Problem Frames 10 & 111 Decomposition and Composition Problem Frames: Ch. 10,11

2. Problem Frames 10 & 112 How To Decomposing –Heuristics Composing –Frequent compositions –Concerns

3. Problem Frames 10 & 113 Decomposition Identify the core problem Identify ancillary problems Standard decomposition of subproblems Identifying concerns and difficulties Different tempi More than two moods Complex domain or requirement Modeling the user

4. Problem Frames 10 & 114 Patterns Standard decomposition of subproblems Standard ways of addressing concerns Standard ways of separating tempi Standard ways of separating moods Standard ways of modeling the user

5. Problem Frames 10 & 115 Composite Frames Information Display MVC 2-tier client/server architecture with VB and SQL Server

6. Problem Frames 10 & 116 Composition Concerns Commensurability Consistency –Precedence Interference Synchronization

7. Problem Frames 10 & 117 Checkwriting machine Payroll DB Paycheck X C Y4 PD!Y7 CM!E2 Y6 Paychecks - DB W2 machine Payroll DB W2 X C Y4 PD!Y7 WM!E2 Y6 W2 - DB

8. Problem Frames 10 & 118 Payroll input Real world Payroll DB C X Y6 RW!C1 PI!E5 C3 DB - Real world Reports machine Payroll DB Reports X C Y4 MD!Y7 RM!E2 Y6 Reports -DB

9. Problem Frames 10 & 119 Different Tempi Identify all input events and their frequency –Time cards - weekly –New employee form - once per employee –benefit choice - yearly –raise - irregularly (yearly) –W4 form - yearly

10. Problem Frames 10 & 1110 Timecard Entry Timecard Payroll DB C X Y8 TC!C5 TE!E6 C7 DB - Timecards Employee Update Employee Info. Payroll DB C X Y4 EI!C1 EU!E2 C3 DB - Emp. Information

11. Problem Frames 10 & 1111 More than Two Moods Domain - what is - indicative Requirement, specification - what we want - optative ?? - what we do when we don’t get what we want - Super-optative Super-optative mood is a separate problem!

12. Problem Frames 10 & 1112 The amount earned is the salary times the hours worked, except that overtime counts for time-and-a-half. Every payday, pay all the timecards. If a timecard is missed or a salary is wrong, just pay it the next cycle.

13. Problem Frames 10 & 1113 How to improve a problem description? Decompose into simple problems –try heuristics until you can’t think of any more –reuse patterns when you can see them Make sure they compose properly –think about each composition concern –use well-understood composite frames