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2	Design context
3	Design criteria Cohesion Coupling Information hiding Encapsulation
4	Views UML provides multiple perspectives for describing the software. Static – shows classes class diagram concepts relationships Dynamic – shows objects/components state diagram activity diagram
5	Classes
6	State
7	Mutually reinforcing views
8	Activity diagram
9	Mutual reinforcement
10	Concurrency Sequential one thing at a time Concurrent appears that multiple things happen but really only one at a time Parallel multiple things really do happen at a time
11	Issue - order If two different entities access the same resource does the order in which they access the resource change the result?
12	Units
13	Single process
14	Multiple processes
15	Where does concurrency come from? Multiple independent sources of stimulus people hardware Multiple modules with no interdependence
16	Where does parallelism come from? Availability of hardware to implement concurrency
17	Synchronization
18	The goal The goal is to have sufficient semantics to fully describe a system.
19	Exercise Design a “to do list” program that can List tasks by time and date Allow addition, deletion, and modification of tasks Allow user to specify that a task is to be repeated. Daily, weekly, monthly Print a daily schedule Allow multiple users to access the same list from anywhere Criteria: use as many design patterns as possible; appropriateness of chosen architecture; completeness of the design document; clarity of description Conditions: team of 2; due October 26^th by 9 am via email; 4 pts