gdpstatemc.h

《SymbianOSC手机应用开发》源码

// gdpstatemc.h
//
// Copyright (c) 1999 Symbian Ltd.  All rights reserved.
//

#ifndef __GDPSTATEMC_H__
#define __GDPSTATEMC_H__

#include "gdpmain.h"
#include <e32std.h>
#include <e32base.h>


/*
 * class CGdpStateMachine 
 *
 * Provides an abstract state machine framework, by extending the
 * active object framework through use of the state pattern.
 *
 * Error conditions that are not caught & handled by individual states
 * are passed back to the concrete state machine to handle, if appropriate.
 *
 */


class CGdpStateMachine : public CActive
//---------------------
	{
public:
	~CGdpStateMachine();

	class TState
		{
	public:
		virtual void EnterL()=0;
		virtual TState* CompleteL()=0;
		virtual TState* ErrorL(TInt aCode)=0;
		virtual void Cancel()=0;
		};

protected:
	CGdpStateMachine(TPriority aPriority);
	void ChangeState(TState* aNextState);
	inline TState* CurrentState();
	void SetNextState(TState* aNextState);
	void ReEnterCurrentState();
	//Methods to be implemented by concrete state-machines
	virtual TState* ErrorOnStateEntry(TInt aError)=0;
	virtual TState* ErrorOnStateExit(TInt aError)=0;

private:
	// Overrides of CActive functions
	void RunL();
	void DoCancel();
	TInt RunError(TInt aError);

private:
	TState*  iState;
	};

/************** INLINES DECLARATIONS *****************/

CGdpStateMachine::TState* CGdpStateMachine::CurrentState() { return iState; }

/*****************************************************/


#endif