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<concept id="GUID-5592E9C1-D490-538F-9B11-5EFB72DEDBE2" xml:lang="en"><title>File

Based Dictionary Store</title><shortdesc><codeph>CDictionaryFileStore</codeph> is a concrete implementation

of a dictionary store and uses a file store in its implementation.</shortdesc><prolog><metadata><keywords/></metadata></prolog><conbody>

<p>Although the need for a file based dictionary store is driven by the application

architecture, the following code fragments illustrate the way this store can

be used.</p>

<p>The code fragments shown here create and read a file based dictionary store.

This dictionary store is differentiated from other dictionary stores by the

UID whose value is <codeph>0x0001</codeph>.</p>

<p>It should be noted that the values assigned to the UIDs are purely <i>arbitrary</i> and

are used for <i>illustrative purposes only</i>.</p>

<section id="GUID-819A7F9D-92C0-49AC-BD0B-ED4C66B59C15"><title>Creating the

dictionary store</title> <p>This code fragment constructs an object of type <codeph>TClass</codeph> and

stores it in the dictionary store, associating the stream with the UID whose

value is 0x0002.</p> <p>Note that a dictionary write stream is needed to write

streams to a dictionary store.</p> <codeblock id="GUID-AF74B440-E5A9-5A47-84E1-09E2243BB911" xml:space="preserve">_LIT(KFileName,"C:\\data\\stdict.dat");

_LIT(KTxtData,"Text type data"):

TParse dictionaryname;

...

fsSession.Parse(KFileName,dictionaryname);

... 

           // Open the dictionary store (create if it doesn't exist)

CDictionaryStore* dictstore = CDictionaryFileStore::OpenLC (fsSession, dictionaryname.FullName(),TUid::Uid(0x0001) );

           // Construct a TClass and put some data into it

TClass thedata;

thedata.iFixBuf    = KTxtData;

thedata.iUintValue = 1;

thedata.iIntValue  = -2; 

thedata.iRealValue = 3.4;

           // construct the dictionary write stream and

           // associate the stream with the UID

           // whose value is 0x0002

RDictionaryWriteStream out;

out.AssignLC(*dictstore,TUid::Uid(0x0002));

           // write the TClass data to the stream

out << thedata;

           // Commit changes to the stream

out.CommitL(); 

           // Cleanup the dictionary stream object

CleanupStack::PopAndDestroy();

           // Now commit all changes to the store

dictstore->CommitL();

           // Close the dictionary store (closes the

           // associated file and destroys the 

           // dictionary store object)

CleanupStack::PopAndDestroy(); </codeblock> </section>

<section id="GUID-549EA1EF-A892-41FF-B5CE-F83AECA266B4"><title>Reopening the

dictionary store</title><p>This code fragment re-opens the dictionary store

and restores the <code>TClass</code> object from the stream associated

with the UID whose value  is &lt;code&gt;0x0002&lt;/code&gt; </p><codeph>0x0002</codeph><codeblock xml:space="preserve">_LIT(KFileName,"C:\\data\\stdict.dat");

TParse dictionaryname;

...

fsSession.Parse(KFileName,dictionaryname);

...

           // Open the dictionary store 

CDictionaryStore* dictstore=CDictionaryFileStore::OpenLC(fsSession, dictionaryname.FullName(), TUid::Uid(0x0001) );

           // construct the dictionary read stream.

           // Prepare to read the stream associated with

           // the unique identifier whose value is 0x0002

RDictionaryReadStream in;

in.OpenLC(*dictstore,TUid::Uid(0x0002));

            // Construct a TClass object ...

TClass thedata;

            // ... and read data from the stream

in >> thedata;

            // Cleanup the dictionary stream object

            // and ...

            // Close the dictionary store

            // (closes the associated file and destroys the

            // dictionary store object)

CleanupStack::PopAndDestroy(2);

</codeblock> </section>

</conbody><related-links>

<link href="GUID-79F39C97-75E8-5DB1-B976-8FE76E6E60C9.dita"><linktext>Dictionary

stores</linktext></link>