Type Here to Get Search Results !

Advanced States and Transitions in UML State Machines

Advanced States and Transitions
  • Entry and Exit Actions 
  • Internal Transitions
  • Do-Activities
  • Deferred Event
Entry and Exit Actions: 
  • Entry actions are actions done upon entry of a state and are shown by the keyword event 'entry' with an appropriate action 
  • Exit actions are actions done upon exit from a state marked by the keyword event 'exit', together with an appropriate action
cse study zone,csestudies4you,estudies4you,Advanced States and Transitions in State Machines,Concurrent Substates in uml,substates in uml,uml substates,History States in uml,Sequential Substates in uml,

Internal Transitions: 
  • Internal transitions are events handled internally without leaving the state 
  • Internal transitions may have events with parameters and guard conditions
Do-Activities: 
  • Activities that make use of object's idle time when inside a state
  • 'do' transition specifies the work done inside a state after the entry action is dispatched
Deferred Event: 
  • A deferred event is a list of events whose occurrence in the state is postponed until a state in which the listed events are not deferred 
  • It becomes active at the time they occur and may trigger transitions as if they had just occurred 
  • A deferred event is specified by listing the event with the special action 'defer'
SUB STATES
  • Sequential Substates
  • History States
  • Concurrent Substates
Sequential Substates
  • Sequential substates are those substates in which an event common to the composite states can easily be exercised by each state inside it at any time 
  • Sequential substates partition the state space of the composite state into disjoint states 
  • A nested sequential state machine may have at most one initial state and one final state
cse study zone,csestudies4you,estudies4you,Advanced States and Transitions in State Machines,Concurrent Substates in uml,substates in uml,uml substates,History States in uml,Sequential Substates in uml,

History States 
  • It allows composite state that contains sequential substates to remember the last substate that was active in it prior to the transition from the composite state 
  • A shallow history state is represented as a small circle containing the symbol 'H' 
  • The first time entry to a composite state doesn't have any history 
  • The symbol 'H' designates a shallow history, which remembers only the history of the immediate nested state machine 
  • The symbol 'H*' designates deep history, which remembers down to the innermost nested state at any depth 
  • If there is only one level of nesting, shallow and deep history states are semantically equivalent
cse study zone,csestudies4you,estudies4you,Advanced States and Transitions in State Machines,Concurrent Substates in uml,substates in uml,uml substates,History States in uml,Sequential Substates in uml,

Concurrent Substates 
  • Concurrent substates specify two or more state machines that execute in parallel, in the context of the enclosing object 
  • Execution of these concurrent substates continues in parallel 
  • These substates wait for each other to finish to join back into one flow 
  • A nested concurrent state machine does not have an initial, final, or history state
cse study zone,csestudies4you,estudies4you,Advanced States and Transitions in State Machines,Concurrent Substates in uml,substates in uml,uml substates,History States in uml,Sequential Substates in uml,


Tags

Top Post Ad

Below Post Ad