/*

* Copyright (c) 2009 Nokia Corporation and/or its subsidiary(-ies).

* All rights reserved.

* This component and the accompanying materials are made available

* under the terms of "Eclipse Public License v1.0"

* which accompanies this distribution, and is available

* at the URL "http://www.eclipse.org/legal/epl-v10.html".

*

* Initial Contributors:

* Nokia Corporation - initial contribution.

*

* Contributors:

*

* Description: Abstract interface for handling property change events.

*

*/

#ifndef CFMRADIOPROPERTYOBSERVER_H

#define CFMRADIOPROPERTYOBSERVER_H

#include <e32base.h>

#include <e32property.h>

/**

 * MFMRadioPropertyChangeObserver

 *

 * Abstract interface for handling property change events.

 */

class MFMRadioPropertyChangeObserver

{

public:

    /**

    * This is a callback function which is called when a property value of 

    * type int is changed.

    *

    * @param aCategory UID of Publish And Subscribe category

    * @param aKey subkey to specify the category event; to be used with 

    * Publish And Subscribe

    *

    * @param aValue the new value

    */

    virtual void HandlePropertyChangeL(

        const TUid& aCategory, 

        const TUint aKey, 

        const TInt aValue ) = 0;

	/**

    * This is a callback function which is called when a property value of 

    * type text is changed.

    *

    * @param aCategory UID of Publish And Subscribe category

    * @param aKey subkey to specify the category event; to be used with 

    * Publish And Subscribe

    * @param aValue the new value

    **/

    virtual void HandlePropertyChangeL( 

        const TUid& aCategory, 

        const TUint aKey, 

        const TDesC& aValue ) = 0;        

	/**

    * This is a callback function which is called when a property value of 

    * type byte array is changed.

    *

    * @param aCategory UID of Publish And Subscribe category

    * @param aKey subkey to specify the category event; to be used with 

    * Publish And Subscribe

    * @param aValue the new value

    **/

    virtual void HandlePropertyChangeL( 

        const TUid& aCategory, 

        const TUint aKey, 

        const TDesC8& aValue ) = 0;        

    /**

    * This is a callback function which is called when a P&S components 

    * returns an error

    *

    * @param aCategory UID of Publish And Subscribe category

    * @param aKey subkey to specify the category event

    * @param aError an error code

    */

    virtual void HandlePropertyChangeErrorL(

        const TUid& aCategory, 

        const TUint aKey, 

        TInt aError) = 0;    

};

/**

 * Observer class that observes changes of Property values and propogates 

 * them further.

 * The class defines a handle to a property, a single data value representing

 * an item of state information.

 *

 */

 class CFMRadioPropertyObserver : public CActive

	{  

 public:

    /**

     * Property type. Cannot use RProperty::TType because EByteArray == EText.

     */

    enum TFMRadioPropertyType

    	{

    	EFMRadioPropertyInt, // Integral property type.

    	EFMRadioPropertyByteArray, // Byte-array (8 bit), max size 512 bytes

    	EFMRadioPropertyText // Text (16 bit), max size 512 bytes

    	};

    /**

     * Two-phased constructor.

     *

     * @param aObserver a reference to the observer interface implementer

     * @param aCategory UID of Publish And Subscribe category

     * @param aKey subkey to specify the category event; to be used with 

     * Publish And Subscribe

     * @param aPropertyType property type to observe

     */

    static CFMRadioPropertyObserver* NewL(

        MFMRadioPropertyChangeObserver& aObserver, 

        const TUid& aCategory, 

        const TUint aKey, 

        const TFMRadioPropertyType aPropertyType);

    /**

     * Two-phased constructor.

     *

     * @param aObserver a reference to the observer interface implementer

     * @param aCategory UID of Publish And Subscribe category

     * @param aKey subkey to specify the category event; to be used with 

     * Publish And Subscribe

     * @param aPropertyType property type to observe

     */

    static CFMRadioPropertyObserver* NewLC(

        MFMRadioPropertyChangeObserver& aObserver, 

        const TUid& aCategory, 

        const TUint aKey, 

        const TFMRadioPropertyType aPropertyType);

    /**

     * Destructor.

     */

    ~CFMRadioPropertyObserver();

    /**

     * Subscribes the object to listen to the specified key. Does nothing if already active.

     * Must be called after construction, or after calling Cancel().

     */

    void ActivateL();

    /**

     * Returns current integer property value

     * @param aUpdate ETrue if the cache value should be updated

     * 

     * @return int value

     */	

	TInt ValueInt( TBool aUpdate = EFalse );

	/**

     * Returns current byte array property value

     ** @param aUpdate ETrue if the cache value should be updated

     * 

     * @return byte array value

     */	

	const TDesC8& ValueDes8( TBool aUpdate = EFalse );

	/**

     * Returns current text property value

     * * @param aUpdate ETrue if the cache value should be updated

     *

     * @return text value

     */	

	const TDesC& ValueDes( TBool aUpdate = EFalse );

private:

    /**

     * C++ default constructor overload.

     * Two-phased constructor.

     *

     * @param aObserver a reference to the observer interface implementer

     * @param aCategory UID of Publish And Subscribe category

     * @param aKey subkey to specify the category event; to be used with 

     * Publish And Subscribe

     * @param aPropertyType property type to observe

     */

	CFMRadioPropertyObserver(

	    MFMRadioPropertyChangeObserver& aObserver, 

	    const TUid& aCategory, 

	    const TUint aKey, 

	    const TFMRadioPropertyType aPropertyType);

    /**

     * By default Symbian 2nd phase constructor is private.

     **/

    void ConstructL(); 

    // from base class Cactive

    /**

     * From CActive

     *

     * @see CActive::RunL()

     */

    void RunL();

    /**

     * From CActive, 

     * 

     * @see CActive::DoCancel()

     */

    void DoCancel();

private: // data

 	/** 

 	 * Value of a subscribed category property of type int. 

 	 */

 	TInt iValueInt;

 	/** 

 	 * Value of a subscribed category property of type byte array. 

 	 */

 	HBufC8* iValueByteArray;

 	/** 

 	 * Value of a subscribed category property of type text. 

 	 */

 	HBufC* iValueText;

    /** 

     * Handle to Publish And Subscribe component

     */ 

    RProperty iProperty;

    /**

     * Observer to be notified when particular Property value has changed

     */

    MFMRadioPropertyChangeObserver& iObserver;

    /** 

     * UID of Publish And Subscribe category

     */

    TUid iCategory;

    /**

     * Subkey to be used with Publish And Subscribe

     */

    TUint iKey;

    /** 

     * Type of the observed property. 

     */

    TFMRadioPropertyType iPropertyType;

	};

#endif  // CFMRADIOPROPERTYOBSERVER_H