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State Diagrams. Lesson 9. Agenda. Weekly Schedule-SLATE Assignment No 2 Solutions to ICE’s posted on SLATE Today State charts – continued... I-C-E-06 Two ways of modelling Summarize Requirements Gathering Process Car Rental System – Case Study
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State Diagrams Lesson 9
Agenda • Weekly Schedule-SLATE • Assignment No 2 • Solutions to ICE’s posted on SLATE • Today • State charts – continued... • I-C-E-06 • Two ways of modelling • Summarize Requirements Gathering Process • Car Rental System – Case Study • Introduce System Sequence Diagrams (SSDs) • ICE-07 Object Oriented Methodologies
The Big Picture Object Oriented Methodologies
Typical Amazon Package Tracking Status Report Object Oriented Methodologies
Review I-C-E-06 • Two Versions Object Oriented Methodologies
Class example… • Car Rental System – Posted on SLATE Week09 Object Oriented Methodologies
Summarize:Rules for Developing Statecharts • [1] Select the classes that will require statecharts • [2] List all the status conditions for each group • [3] Specify transitions that cause object to leave the identified state • [4] Sequence state-transition combinations in correct order Object Oriented Methodologies
Rules for Developing Statecharts (continued) • [5] Identify concurrent paths. • [6] Look for additional transitions • [7] Expand each transition as appropriate • [8] Review and test each statechart Object Oriented Methodologies
Practice Exercise • See SLATE for a posted exercise Object Oriented Methodologies
The Big Picture SYST39409 - Object Oriented Methodologies
Identifying Inputs and Outputs—the System Sequence Diagram • System sequence diagram (SSD) • Describes flow of information • Identifies interaction between actors and system • Message oriented SYST39409 - Object Oriented Methodologies
SSD Notation • Actor “interacts” with the system via input/output • SSDs use object notation • Box (rectangle) refers to individual object • Name of the object underlined • Messages sent/received by objects, not classes • Lifeline • Extension of object or actor for duration of the SSD • Indicates sequence of the messages sent/received SYST39409 - Object Oriented Methodologies
SSD Notation (continued) • Message syntax can take several forms • Depends on send/return direction • Message semantics: actions (like commands) invoked on destination object SYST39409 - Object Oriented Methodologies
Developing a System Sequence Diagram • Begin with detailed description of use case • Fully developed form • Activity diagrams • (4) step process for turning activity diagram into SSD • [1] Identify the input messages • [2] Describe messages from external actor to system • [3] Identify/apply special conditions to input messages • [4] Identify and add the output return messages SYST39409 - Object Oriented Methodologies
An SSD of the Simplified Telephone Order Scenario for the Create New Order Use Case
Developing a System Sequence Diagram (continued) • Names of messages reflect services performed • Important principle for identifying data parameters • Base the list on the class diagram • Attributes from the classes listed as parameters • Iteratively define input/output parameters around workflows • Objective: discovery and understanding SYST39409 - Object Oriented Methodologies
For Next Class • Read & Study Chapter 6 Pages 237 -246 • What comes next? • Sequence Diagrams Object Oriented Methodologies