/*

* Copyright (c) 2006-2006 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:  Defines a transaction

*

*/

#ifndef C_CPSTRANSACTION_H

#define C_CPSTRANSACTION_H

#include <e32base.h>

/**

 * Pure virtual base class for transactions.

 */

NONSHARABLE_CLASS( MPSTransactionEntity )

    {

public:

    /**

     * Begins an explicit transaction.

     */

    virtual void BeginTransactionL() = 0;

    /**

     * Commits changes done during the transaction.

     */

    virtual void CommitL() = 0;

    /**

     * Reverts changes done during the transaction.

     */

    virtual void Rollback() = 0;

    };

/**

 * Defines a transaction.

 *

 * Transactions must be created whenever any value of the transaction is to be modified. They provide

 * means to synchronize transaction item updates so that they cannot be updated simultaneously by two clients.

 *

 * Transactions cannot be created as is, as they must be created through transactable entities.

 *

 * To create a transaction with a preset, use CPSPresetInterface::CreateTransactionL() or CPSPresetInterface::CreateTransactionLC().

 *

 * When a transaction is started, the transaction entity remains in locked state until it is either committed or rollbacked.

 */

NONSHARABLE_CLASS( CPSTransaction ) : public CBase

    {

public:

    /**

     * Destructor

     */

    IMPORT_C ~CPSTransaction();

    /**

     * Completes the transaction, committing all changes done to the preset.

     */

    IMPORT_C void CommitL();

    /**

     * Completes the transaction, reverting all changes done to the preset.

     */

    IMPORT_C void Rollback();

public:

    /**

     * Creates a new preset transaction object.

     * 

     * @param   aEntity     The transaction entity to start the transaction with.

     */

    static CPSTransaction* NewL( MPSTransactionEntity& aEntity );

private:

    /**

     * Constructor.

     * 

     * @param   aEntity     The transaction entity to start the transaction with.

     */

    CPSTransaction( MPSTransactionEntity& aEntity );

    /** 

     * Second-phase constructor.

     */

    void ConstructL();     

private:

    /** The transaction entity. */

    MPSTransactionEntity& iEntity;

    /** Extension. */

    TAny* iExtension;

    };

#endif // C_CPSTRANSACTION_H