SWE 760 Real-Time Software Design. Lecture 6 Dynamic Interaction Modeling for Real-Time Embedded Systems

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1 SWE 760 Real-Time Software Design Lecture 6 Dynamic Interaction for Real-Time Embedded Systems Reference: H. Gomaa, Chapters 9 - Real-Time Software Design for Embedded Systems, Cambridge University Press, 206 Hassan Gomaa Dept of Computer Science George Mason University Fairfax, VA Copyright 206 Hassan Gomaa All rights reserved. No part of this document may be reproduced in any form or by any means, without the prior written permission of the author. Copyright 206 H. Gomaa T Figure 4. COMET/RTE life cycle model User System Structural Requirements Analysis Design Incremental Software Construction Incremental Software Integration Incremental Prototyping System Testing Customer Copyright 206 Hassan Gomaa 2 A-

2 Analysis Static Define entity classes and relationships Dynamic State Machine Real-time systems are highly state dependent Actions depend on input event AND current state Object Structuring Determine objects that realize each use case Dynamic Interaction Determine sequence of interactions among objects Copyright 206 H. Gomaa 3 Copyright 206 H. Gomaa Dynamic Interaction Use cases realized in Dynamic Model Show objects participating in each use case Determine how objects participate in use case Use object structuring criteria to determine objects Stereotype for each object structuring criterion Shows sequence of object interactions in use case Depict on communication diagram or sequence diagram State dependent control objects Modeled using statecharts Dynamic Approach to determine how objects interact with each other to support use case 4 A-2

3 Dynamic Determine how objects interact with each other to support use case Start with external event from actor Determine objects needed to support use case Determine sequence of internal events following external event Depict on communication diagram or sequence diagram Stateless (non state-dependent) Dynamic State dependent Dynamic Copyright 206 H. Gomaa dm-5 Stateless Dynamic Start with use case Determine boundary objects Receives external events from actor Determine internal objects Receive messages from boundary objects Determine object interactions Sequence of messages passed Develop main interaction sequence (scenario) Develop alternative sequences For alternative branches of use case E.g, for error handling or less frequently occurring conditions Copyright 206 H. Gomaa dm-6 A-3

4 Example of Stateless Dynamic Figure 9.4 Send Vehicle Status use case «timer actor» «human actor» Send Vehicle Status Timer (primary actor) Driver (secondary actor) Copyright 206 H. Gomaa 7 Example of Stateless Dynamic «external timer» : DigitalTimer «timer» : VehicleTimer «entity» : VehicleData «output» : VehicleDisplay Output Driver : Timer Event 2: read(out location, out speed) 3: Vehicle Status 4: Vehicle Status Fig 9.5: Sequence diagram for Send Vehicle Status use case Copyright 206 H. Gomaa 8 A-4

5 Example of Stateless Dynamic Copyright 206 H. Gomaa 9 State Dependent Dynamic Object interaction controlled by statechart(s) Control object Executes statechart Activates/deactivates other objects For each use case Determine objects participating in use case Determine sequence of object communication Develop statechart for control object For each event that arrives at control object Determine state transition from current state to next state Determine actions and activities to be executed Determine objects required to perform actions and activities Copyright 206 H. Gomaa 0 A-5

6 Copyright 206 H. Gomaa «external user» RailOperator..* RailOperationsDisplay ArrivalSensor ApproachingSensor..*..* Interacts with..*..* MotorActuator DoorActuator DepartureSensor ProximitySensor LocationSensor SpeedSensor..*..*..*..* «software system» LightRailControl System Communicates with Communicates with..*..*..*..* TrainDisplay TrainAudioDevice StationDisplay StationAudioDevice..* DoorSensor..* «external system» RailroadCrossingControl..* «external system» WaysideMonitoringSystem Copyright 206 H. Gomaa Figure 2.3 Light Rail Control Software system context block diagram 2 A-6

7 Figure 2.4 Light Rail Control System actors and use cases: Light Rail Operations use case package Railroad Media «use case package» LightRailOperations Control Train Operation Approaching Sensor «include» «include» «include» Arrive at Station Control Train at Station Depart from Station Departure Sensor Arrival Sensor Door Actuator Door Sensor Copyright 206 H. Gomaa Motor 3 Figure 2.5 Light Rail Control System: Train Dispatch and Suspend use case package «use case package» LightRailOperations Arrive at Station Control Train at Station Depart from Station «use case package» TrainDispatchAnd Suspend «include» «include» «include» «include» Suspend Train Dispatch Train Door Sensor Rail Operator Door Actuator Copyright 206 H. Gomaa Railroad Media 4 A-7

8 Figure 2.6 Light Rail Control System: Railroad Hazard Detection «use case package» LightRailOperations Arrive at Station Depart from Station «use case package» RailroadHazardDetection «extend» «extend» «extend» «extend» Detect Hazard Presence Detect Hazard Removal Copyright 206 H. Gomaa Proximity Sensor Motor 5 Figure 2.9 State machine for Arrive at Station use case Doors Opening Entry / Open Doors Stopped / Send Arrived Copyright 206 H. Gomaa Approached / Decelerate Arrived/ Stop Cruising Approaching Entry / Send Approached Stopping 6 A-8

9 Figure 2.0 State machine for Control Train at Station use case Doors Opening Entry / Open Doors Opened / Start Timer Doors Open Exit / Close Doors After (Timeout) [All Clear] / Send Departing Doors Closing Copyright 206 H. Gomaa 7 Figure 2. State machine for Depart from Station use case Doors Closing Closed Departed / Send Departed Accelerating Entry / Accelerate Reached Cruising / Cruise Cruising Copyright 206 H. Gomaa 8 A-9

10 Figure 2.2 State machine for Suspend Train use case Out of Service Doors Opening Entry / Open Doors After(Timeout)[Suspending] / Send Out of Service Opened / Start Timer Doors Open Exit / Close Doors Copyright 206 H. Gomaa 9 Copyright 206 H. Gomaa 20 A-0

11 Copyright 206 H. Gomaa 2 Copyright 206 H. Gomaa 22 A-

12 Figure 2.6 Flat state machine for Control Train Dispatch / Send In Service Out of Service Doors Opening Entry / Open Doors After(Timeout)[Suspending] / Send Out of Service After(Timeout)[Hazard] / Start Timer Opened / Start Timer Doors Open Exit / Close Doors Stopped / Send Arrived Departed / Send Departed After (Timeout) [All Clear] / Send Departing Approached / Decelerate Doors Closing Closed Accelerating Reached Cruising / Cruise Entry / Accelerate Cruising Approached / Decelerate Hazard Removed [Not Approaching] / Send Hazard Removed Hazard Detected Hazard Detected Hazard Removed [Not Approaching] / Send Hazard Removed Hazard Detected Stopped / Send Stopped Emergency Halt Emergency Stopping Entry / Emergency Stop, Send Hazard Detected Copyright 206 H. Gomaa Arrived/ Stop Approaching Entry / Send Approached Stopping Hazard Removed [Approaching Station] / Accelerate Slowly, Send Hazard Removed Hazard Removed [Approaching Station] / Accelerate Slowly, Send Hazard Removed 23 Out of Service Dispatch / Send In Service Doors Opening Entry / Open Doors After(Timeout)[Suspending] / Send Out of Service Figure 2.7 Hierarchical state machine for Control Train After(Timeout)[Hazard] / Start Timer Doors Open Opened / Start Timer Exit / Close Doors After (Timeout) [All Clear] / Send Departing Stopped / Send Arrived Doors Closing Emergency Closed Emergency Halt In Motion Departed / Send Departed Accelerating Entry / Accelerate Hazard Removed [Not Approaching] Stopped / Send Stopped Approached / Decelerate Reached Cruising / Cruise Cruising Approached / Decelerate Approaching Entry / Send Approached Hazard Detected Hazard Removed [Approaching Station] / Accelerate Slowly Emergency Stopping Entry / Emergency Stop, Send Hazard Detected Exit: Send Hazard Removed Copyright 206 H. Gomaa Arrived/ Stop Stopping 24 A-2

13 ArrivalSensor ApproachingSensor DepartureSensor ProximitySensor LocationSensor SpeedSensor..*..*..*..*..*..*..* DoorSensor Copyright 206 H. Gomaa «external user» RailOperator Interacts with «software system» LightRailControlSystem «user interaction» «subsystem» RailOperations Interaction RailOperationsDisplay..* Communicates with «service» «subsystem» RailOperations Service «control» «subsystem» TrainControl Subsystem «output» «subsystem» Station Subsystem Figure 2.8 Light Rail Control Software subsystems Communicates with..* MotorActuator..*..*..*..*..*..*..* «external system» WaysideMonitoringSystem «external system» RailroadCrossingControl DoorActuator TrainDisplay TrainAudioDevice StationDisplay StationAudioDevice 25 Copyright 206 H. Gomaa 26 A-3

14 Figure 2.20 Input and output classes for Station Subsystem «output» «subsystem» :StationSubsystem «coordinator» Station Coordinator «output» StationDisplay Output «entity» StationStatus «output» StationAudio Output «output» «hwdevice» StationDisplay «output» «hwdevice» StationAudio Device Copyright 206 H. Gomaa 27 Dynamic Interaction of External Objects with Software System Starting with Use case model system context model From software system context diagram Model software system as one aggregate object Model instances of external objects from From use case model Follow sequence of interactions described in use case Depict interaction with external objects Copyright 206 H. Gomaa 28 A-4

15 Figure 2.2 Sequence diagram for Arrive at Station use case (external objects) :Approaching Sensor «external input device» :ArrivalSensor «external input device» :DoorSensor «software system» :LightRailControl System «external output device» :MotorActuator «external output device» :DoorActuator «external output device» :TrainDisplay «external output device» :TrainAudioDevice : Approach 2:Decelerate 3: Arrive 4: Stop 5: Stopped 6: Open Doors 7: Arrived 8: Arrived Copyright 206 H. Gomaa 29 Figure 2.22 Sequence diagram for Arrive at Station use case (software objects) «input» :ApproachingSensorInput «input» :ArrivalSensorInput «input» :Door SensorInput «state dependent control» :TrainControl «algorithm» :Speed Adjustment «coordinator» :TrainStatusDispatcher «ouput» :MotorOutput «output» :DoorActuatorOutput : Approached 2: Decelerate 3: Decelerate 4: Send Approached 5: Arrived 6: Stop 7: Stop 8: Stopped 9: Stopped 0: Open Doors : Send Arrived Copyright 206 H. Gomaa 30 A-5

16 Copyright 206 H. Gomaa 3 Copyright 206 H. Gomaa 32 A-6

17 Copyright 206 H. Gomaa 33 Copyright 206 H. Gomaa 34 A-7

18 Copyright 206 H. Gomaa 35 Figure 4. COMET/RTE life cycle model User System Structural Requirements Analysis Design Incremental Software Construction Incremental Software Integration Incremental Prototyping System Testing Customer Copyright 206 Hassan Gomaa 36 A-8

19 Analysis Static Define entity classes and relationships Dynamic State Machine Real-time systems are highly state dependent Actions depend on input event AND current state Object Structuring Determine objects that realize each use case Dynamic Interaction Determine sequence of interactions among objects Copyright 206 H. Gomaa 37 Figure 4. COMET/RTE life cycle model User System Structural Requirements Analysis Design Incremental Software Construction Incremental Software Integration Incremental Prototyping System Testing Customer Copyright 206 Hassan Gomaa 38 A-9