conversion to state pattern

#458

Author: Max Coppin
Date: Wed, 23 Jan 2002 03:06

167 lines
5325 bytes

Hi,
Sorry for previous binary posting.
Below is the code I need to convert to the state pattern
This is also availiable for download from www.stmikes.co.uk/max - I hope!
If you can't get the files and would like them please e-mail
maxcoppin@btinternet.com

I really appreciate it!

Thanks people!

Max

main.cpp:-

#include "cdcontroller.h"
#include <iostream.h>
#include <conio.h>
void main()
{

  cdController cd;
 cout <<endl << "Event Play when in Idle state" <<endl;
 cd.processEvent(cdController::PLAY);
 cout << cd.getStatus() <<endl;
 cout <<endl << "Event Stop when in Playing state"<<endl;
 cd.processEvent(cdController::STOP);
 cout << cd.getStatus() <<endl;
 cout <<endl << "Event Stop when in Idle state"<<endl;
 cd.processEvent(cdController::STOP);
 cout << cd.getStatus() <<endl;
 cout <<endl << "Event Play when in Idle state"<<endl;
 cd.processEvent(cdController::PLAY);
 cout << cd.getStatus() <<endl;
 cout <<endl << "Event End_Of_Last_Track when in Play state"<<endl;
 cd.processEvent(cdController::END_OF_LAST_TRACK);
 cout << cd.getStatus() <<endl;
  getch();
}


cdcontroller.h:-


// cdController.h: interface for the cdController class.
//
//////////////////////////////////////////////////////////////////////

#if
!defined(AFX_CDCONTROLLER_H__B8972782_F2D4_11D5_84B5_EEF8B4A7605C__INCLUDED_
)
#define AFX_CDCONTROLLER_H__B8972782_F2D4_11D5_84B5_EEF8B4A7605C__INCLUDED_

#if _MSC_VER > 1000
#pragma once
#endif // _MSC_VER > 1000

#include <afx.h>

class cdController
{
public:

//Enumerated types
 enum EState {IDLE ,PLAYING};
 enum EEvent {PLAY, STOP,END_OF_LAST_TRACK};

 void processEvent(EEvent e);
 cdController();
 virtual ~cdController();
 CString getStatus();

private:
 CString stateToCString(EState s);
 CString eventToCString(EEvent e);
 void changeState(EState s);

 EState _state, _prevState;
 EEvent _event;
};

#endif //
!defined(AFX_CDCONTROLLER_H__B8972782_F2D4_11D5_84B5_EEF8B4A7605C__INCLUDED_
)


cdcontroller.cpp:-

// cdController.cpp: implementation of the cdController class.
//
//////////////////////////////////////////////////////////////////////

#include "cdController.h"
//#include <iostream.h>
#include <afxtempl.h>

//////////////////////////////////////////////////////////////////////
// Construction/Destruction
//////////////////////////////////////////////////////////////////////

cdController::cdController()
{
//set initial state
 _state = IDLE;
}

cdController::~cdController()
{

}

void cdController::processEvent(EEvent e)
{
  _event = e;
 _prevState = _state;
 switch (_state)
 {
  case IDLE   : if (e == PLAY)
            changeState(PLAYING);
          break;

  case PLAYING : switch (e)
          {
           case STOP : changeState(IDLE);break;
           case END_OF_LAST_TRACK : changeState(IDLE);break;
          }
 }
}

void cdController::changeState(EState s)
{
 _state = s;
}

CString cdController::getStatus()
{ CString s;
 s="Previous state : " + stateToCString(_prevState) + "\t"
  + "Event : " + eventToCString(_event) + "\t"
  + "Current state : " +  stateToCString(_state);
 return s;
}

CString cdController::stateToCString(EState s)
{
//Have to convert enumerated type to CString
//so that it can be output to the screen as text
 switch (s)
 {
 case IDLE   : return "IDLE"; break;
 case PLAYING : return "PLAYING"; break;
 default    : return "UNKOWN STATE";
 }
}

CString cdController::eventToCString(EEvent e)
{
//Have to convert enumerated type to CString
//so that it can be output to the screen as text

 switch (e)
 {
 case PLAY      : return "PLAY"; break;
 case STOP      : return "STOP"; break;
 case END_OF_LAST_TRACK : return "END_OF_LAST_TRACK"; break;
 default       : return "UNKOWN EVENT";
 }
}

Re: conversion to state pattern

#460

Author: Robert C. Martin
Date: Wed, 23 Jan 2002 19:08

176 lines
5932 bytes

The following is the translation of your CDController to the state
pattern.  


==================cdcontroller.h===============================
#ifndef FSM_CDControllerFSM
#define FSM_CDControllerFSM

#include <stddef.h>

class CDControllerFSM;

//----------------------------------------------
// CDControllerFSMState: The base state class
//----------------------------------------------
class CDControllerFSMState
{
  public: 
    virtual const char* StateName() const = 0;
    virtual void Stop( CDControllerFSM& );
    virtual void Play( CDControllerFSM& );
    virtual void End( CDControllerFSM& );
};

//----------------------------------------------
// State: Idle
//----------------------------------------------
class CDControllerFSMIdleState : public CDControllerFSMState
{
  public: 
    virtual const char* StateName() const
        { return "Idle"; }
    virtual void Play( CDControllerFSM& );
};

//----------------------------------------------
// State: Playing
//----------------------------------------------
class CDControllerFSMPlayingState : public CDControllerFSMState
{
  public: 
    virtual const char* StateName() const
        { return "Playing"; }
    virtual void Stop( CDControllerFSM& );
    virtual void End( CDControllerFSM& );
};

//----------------------------------------------
// CDControllerFSM: The Finite State Machine class
//----------------------------------------------
class CDControllerFSM
{
  public: 
    // Static State variables
    static CDControllerFSMIdleState Idle;
    static CDControllerFSMPlayingState Playing;

    CDControllerFSM(); // default Constructor

    // Event functions
    void Stop() { itsState->Stop( *this ); }
    void Play() { itsState->Play( *this ); }
    void End() { itsState->End( *this ); }

    // State Accessor functions
    void SetState( CDControllerFSMState& theState ) 
    { itsState = &theState; }
    CDControllerFSMState& GetState() const 
    { return *itsState; }

    const char* GetCurrentStateName() const 
    { return itsState->StateName(); }

  private:
    CDControllerFSMState* itsState;
};

#endif



=========================cdcontroller.cpp===================


#include "cdcontroller.h"

CDControllerFSMIdleState CDControllerFSM::Idle;
CDControllerFSMPlayingState CDControllerFSM::Playing;

//----------------------------------------------
// Default Event Functions
//----------------------------------------------

void CDControllerFSMState::Stop(CDControllerFSM& s)
  { s.FSMError("Stop", s.GetState().StateName()); }

void CDControllerFSMState::Play(CDControllerFSM& s)
  { s.FSMError("Play", s.GetState().StateName()); }

void CDControllerFSMState::End(CDControllerFSM& s)
  { s.FSMError("End", s.GetState().StateName()); }


//----------------------------------------------
// Idle Actions and Transitions
//----------------------------------------------

void CDControllerFSMIdleState::Play( CDControllerFSM& s )
{
    s.SetState(CDControllerFSM::Playing);
}

//----------------------------------------------
// Playing Actions and Transitions
//----------------------------------------------


void CDControllerFSMPlayingState::Stop( CDControllerFSM& s )
{
    s.SetState(CDControllerFSM::Idle);
}


void CDControllerFSMPlayingState::End( CDControllerFSM& s )
{
    s.SetState(CDControllerFSM::Idle);
}

//----------------------------------------------
// State Machine Constructor: CDControllerFSM
//  set Initial State to: Idle
//
//----------------------------------------------
CDControllerFSM::CDControllerFSM() 
 : itsState(&Idle)
{
}

=======================================

This code was generated by SMC from the following input file:

FSMName CDControllerFSM
Context CDController
Initial Idle
FSMGenerator smc.generator.cpp.SMCppGenerator
{
  Idle
  {
    Play  Playing  {}
  }

  Playing
  {
    Stop  Idle  {}
    End   Idle  {}
  }
}

You can get SMC from the resources section of www.objectmentor.com





Robert C. Martin    | "Uncle Bob"              | Software Consultants
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"One of the great commandments of science is:
    'Mistrust arguments from authority.'" -- Carl Sagan

Re: conversion to state pattern

#461

Author: Sandeep
Date: Thu, 24 Jan 2002 02:34

9 lines
1561 bytes

The following articles will guide to in converting to the state pattern:

http://www.eventhelix.com/RealtimeMantra/HierarchicalStateMachine.htm

http://www.eventhelix.com/RealtimeMantra/StateMachineInheritance.htm

Sandeep
--
www.EventHelix.com - Realtime and Embedded Software Development

🚀 go-pugleaf

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