/*

* Copyright (c) 2008-2009 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:    This class caches resource strings

*

*/

#ifndef _GLXSTRINGCACHE_H_

#define _GLXSTRINGCACHE_H_

// INCLUDES

#include <e32cmn.h>

#include <e32std.h>

#include <e32base.h>

// CLASS DECLARATION

/**

 *  CGlxStringCache class 

 *

 *  This class caches resource strings.

 *  It maintains a mapping between the resource id and the string

 *  @author Rowland Cook

 */

NONSHARABLE_CLASS(CGlxStringCache) : public CBase

    {

public:

	/** 

	 * Two-phase constructor

	*/

	static IMPORT_C CGlxStringCache* NewL();	

	/**

	 * destructor

	 */

    ~CGlxStringCache();    

    /**

	 * Loads a string from a resurce file

	 *

	 * @param aResourceFile - name of the resource file (does not contain the path).

	 * @param aResourceId - Id of the string to be loaded

	 * @return HBufC* containing the required string.

	 */	

    IMPORT_C HBufC* LoadLocalizedStringLC(const TDesC& aResourceFile, const TInt aResourceId);

private:

    /**

     *  CGlxStringItem class 

     *

     *  This class encapsulates a resource id and it's associated string.

     */

    NONSHARABLE_CLASS(CGlxStringItem) : public CBase

        {

    public:

    	/**

    	 * NewL

    	 * @param the resource id

    	 * @param the string

    	 * use this constructor prior to calling InsertL() (Above).

    	 */

        static CGlxStringItem* NewL(TInt aId, HBufC* aString);

    	/**

    	 * Constructor

    	 * @param the resource id

    	 * use this constructor directly to create a dummy class typically used before calling Find() (Above).

    	 */

        CGlxStringItem(TInt aId);

    	/**

    	 * destructor

    	 */

        ~CGlxStringItem();

    	/**

    	 * GetId

    	 * @return the Id

    	 */

        TInt GetId() const;

    	/**

    	 * GetString

    	 * @return HBufC* to the string

    	 */

        HBufC* GetString();

    private:    

    	/**

    	 * 2nd Phase constructor

    	 * @param the string. Creates own copy of string

    	 */

        void ConstructL(HBufC* aString);

    private:

        /// The resource id of the string

        TInt    iId;

        /// HBufC containing the string (Owned)

        HBufC*  iString;

        };

private:

	/**

	 * Default Constructor

	 */

    CGlxStringCache();

	/**

	 * Searches for a string given the resource id

	 * @param - resource id

	 * @return - an HBufC* to the string. NULL if not found. Ownership of string passed to caller.

	 */

    HBufC* FindL(TInt aId);

	/**

	 * Inserts a string and resource id into the cache

	 * @param - resource id

	 * @return - an HBufC* to the string. NULL if not found. Ownership of string passed to caller.

	 */    

    void InsertL(TInt aId, HBufC* aString);

    /**

     * Count

     * @return number of elements in array

     */ 

    TInt Count();

    /**

     * This method is a callback passed to RPointerArray.InsertInOrder

     * @ref see TLinearOrder.

     * @param first item to be compared

     * @param second item to be compared

     * @return a negative value is Item1 is less than Item2. Zero if Equal, otherwise a positive value

     */

    static TInt OrderById(const CGlxStringCache::CGlxStringItem& aItem1, const CGlxStringCache::CGlxStringItem& aItem2);

    /**

     * This method is a callback passed to RPointerArray.Find

     * @ref see TIdentityRelation.

     * @param first item to be compared

     * @param second item to be compared

     * @return ETrue id Item1 matches Item2, otherwise EFalse

     */

    static TBool MatchById(const CGlxStringCache::CGlxStringItem& aItem1, const CGlxStringCache::CGlxStringItem& aItem2);

    /**

	 * Loads a string from a resurce file

	 *

	 * @param aResourceFile - name of the resource file (does not contain the path).

	 * @param aResourceId - Id of the string to be loaded

	 * @return HBufC* containing the required string.

	 */	

	HBufC* LoadLocalizedStringFromDriveL(const TDesC& aResourceFile, const TInt aResourceId);

private:

    /// Array of CGlxStringItems

    RPointerArray<CGlxStringItem>   iStringCache;

    // remembers the valid resource file name

    TFileName           iResourceFileName;

    };

#endif