State diagrams

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Object orientationPart 4 Dynamic Modeling

• State diagrams
• Interaction diagrams
• Sequence diagrams
• Collaboration diagrams

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Stimulate 2005
System Analysis and Design (SAD) Object
Oriented modeling Part 4 Dynamic modeling state
and interaction diagrams

• Instructor Luz M. Quiroga
• lquiroga_at_hawaii.edu
• University of Hawaii
• Information and Computer Science / Library and
  information Science
• POST 314b 808-956-9988

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State diagrams

• STATE a condition during the life of an object
  during which it
• Satisfies some conditions
• Performs some actions
• Waits for some events
• State transitions

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State diagrams

• State rectangle with round corners
• Event something that takes at a certain point of
  time.
• It triggers a state transition
• It spans a period of time
• Initial (solid, filled circle) and final state
  (bulls eye solid, filled circle surrounded by
  another circle )
• Transition depicted as solid arrow from source
  state to target state
• Transition labeled with name of the event,
  parameters of the event, guard condition and
  /action expression
• Examples registering to a class, dropping from a
  class, getting married, being hired, etc.

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State diagram for the student object

• States, transitions, events

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Sequence diagrams

• Depicts interaction among objects during a
  certain period of time
• One diagram for each use case e.g Class
  registration
• Scenarios
• Messages e.g checkIfopen
• Synchronous needs answer
• Simple transfering the control
• Messages have arguments
• Persistent objects
• Activation time period during which the object
  performs an operation

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Sequence diagram for a class registration
scenario with prerequisites

• Objects, lineline, activation, messages

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Dynamic ModelingState Diagrams

• State
• A condition during the life of an object during
  which it satisfies some conditions, performs some
  actions or waits for some events
• Shown as a rectangle with rounded corners
• State Transition
• The changes in the attribute of an object or in
  the links an object has with other objects
• Shown as a solid arrow
• Diagrammed with a guard condition and action
• Event
• Something that takes place at a certain point in
  time

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Dynamic ModelingSequence Diagrams

• Sequence Diagram
• A depiction of the interaction among objects
  during certain periods of time
• Activation
• The time period during which an object performs
  an operation
• Messages
• Means by which objects communicate with each
  other

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Dynamic ModelingSequence Diagrams

• Synchronous Message
• A type of message in which the caller has to wait
  for the receiving object to finish executing the
  called operation before it can resume execution
  itself
• Simple Message
• A message that transfers control from the sender
  to the recipient without describing the details
  of the communication

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OO paradigm

• Key terms
• Unified Modeling Language (UML)
• Associations, relationships
• Concepts
• Object
• Object class
• Use case
• Class diagram
• Event
• Operation
• Sequence diagram
• State
• State transition

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OO scope
OO Is not LIMITED to Information System
Source Sinha
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Source Martin