diff -r 43e37759235e -r 51a74ef9ed63 Symbian3/SDK/Source/GUID-AA5DEEB2-0B13-5FA8-8494-EC2F5C654FEF.dita --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/Symbian3/SDK/Source/GUID-AA5DEEB2-0B13-5FA8-8494-EC2F5C654FEF.dita Wed Mar 31 11:11:55 2010 +0100 @@ -0,0 +1,56 @@ + + + + + +CentRepExample: +Using Central Repository for Persistent StorageThis example application demonstrates the usage of Central Repository +API for persistent storage. +
Description

Several +Symbian platform components have state and settings information that need +to be persistent. There is also a global state that needs to persist, for +example, default filenames, locale settings, user preferences.

The +CentRep example application first registers a group of settings with the central +repository server. It uses E80000AD.txt, a UTF-16 format +text file to initialise the repository. This text file contains access control +structure and the initial content of the repository. It is recommended to +convert the initialisation text file into a binary file using the central +repository converter tool to speed up the execution.

The application +creates a CRepository object using the CRepository::NewLC() method +to access a repository using its UID. It resets the whole repository using CRepository::Reset() method +with the contents in the initialisation file.

Each setting stored +in the repository will have a unique key to identify the setting. This unique +key is used to read and change the setting by calling the CRepository::Get() and CRepository::Set() methods +respectively. The application moves these keys to a different location using CRepository::Move() method +and deletes them from their original location.

The application also +creates another CRepository object to demonstrate that, at +any given point a repository cannot be opened with READ/WRITE access +by more than one client. In such situations, it is recommended to start a +transaction before a write operation using CRepository::StartTransaction() method. +A transaction guarantees the consistency and persistence of all values read +and written during the transaction.

Finally, the application requests +the central repository server to notify any changes to the original settings.

Related +APIs

    +

  • CRepository - Provides access to a repository.

    • +

  • CRepository::Get()

    • +

  • CRepository::Move()

    • +

  • CRepository::NewLC()

    • +

  • CRepository::Reset()

    • +

  • CRepository::Set()

    • +

  • CRepository::StartTransaction()

    • +
+
Download

Click +on the following link to download the example: CentRepExample.zip

Click: browse to view the example code.

+
Build

The Symbian build process describes +how to build an application.

The CentRepExample builds +an executable called CentRepExample.exe in the standard +location (\epoc32\release\winscw\<build_variant > for CodeWarrior). +After launching the executable, depending on the emulator you are using, you +may need to task away from the app launcher/shell screen to view the console.

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