<?xml version="1.0" encoding="utf-8"?>
<!-- Copyright (c) 2007-2010 Nokia Corporation and/or its subsidiary(-ies) All rights reserved. -->
<!-- This component and the accompanying materials are made available under the terms of the License 
"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: 
-->
<!DOCTYPE concept
  PUBLIC "-//OASIS//DTD DITA Concept//EN" "concept.dtd">
<concept id="GUID-23014C8A-2A0B-5F6A-9BB2-6642E1EC0462" xml:lang="en"><title>Using
Content Processor</title><prolog><metadata><keywords/></metadata></prolog><conbody>
<p>This section explains how to implement the <codeph>MContentProcessor</codeph> interface
to parse, validate and autocorrect an XML document. </p>
<section><title>Introduction</title> <p>The parsed document can also be validated
against a specification and auto-corrected for spelling errors in the validated
text. This can be done by writing three applications - a parser, a validator
and an autocorrector. These applications must implement the <xref href="GUID-7942EDC6-6571-3423-8ECA-D3DB68A78CB6.dita"><apiname>MContentProcessor</apiname></xref> interface. </p> <p>Writing
a content processor is similar to writing a content handler as explained in <xref href="GUID-AF937B6E-7BC0-5B7D-818E-93F7CAFD8808.dita">Parsing an XML Document</xref>. <xref href="GUID-7942EDC6-6571-3423-8ECA-D3DB68A78CB6.dita"><apiname>MContentProcessor</apiname></xref> is
an extension of <xref href="GUID-A6B8386B-29F6-3BEC-9D77-D8E0900DEAC2.dita"><apiname>MContentHandler</apiname></xref>. Each application is writen
by implementing the callback functions of <xref href="GUID-A6B8386B-29F6-3BEC-9D77-D8E0900DEAC2.dita"><apiname>MContentHandler</apiname></xref>.
The only difference is that <xref href="GUID-7942EDC6-6571-3423-8ECA-D3DB68A78CB6.dita"><apiname>MContentProcessor</apiname></xref> has a mechanism
for directing output, so that the output of the parser is the input to the
validator, and the output of the validator is the input to the autocorrector. </p> <p>Direct
output of a content processor by implementing the <xref href="GUID-DCF5D3DD-C7FC-3ED0-86E8-63C5E85795B8.dita"><apiname>SetContentSink()</apiname></xref> function,
so that the parser outputs to the validator and the validator outputs to the
autocorrector. A sequence of several applications linked in this way is called
a <b>Plug-in Chain</b>. </p> </section>
<section><title>Procedure</title> <ol id="GUID-F18654E9-0325-5111-9D00-5196196BD0D5">
<li id="GUID-324DEAF3-690F-5DA0-9DD0-C16533114B0E"><p>Implement the <codeph>MContentProcessor</codeph> interface. </p> </li>
<li id="GUID-97B4EA3B-3CF1-582E-864C-73EF0FA1A1EC"><p>Implement the <xref href="GUID-7942EDC6-6571-3423-8ECA-D3DB68A78CB6.dita#GUID-7942EDC6-6571-3423-8ECA-D3DB68A78CB6/GUID-F33A8F75-B1FB-30DF-B829-DFC6D2CD29E1"><apiname>MContentProcessor::SetContentSink()</apiname></xref> function. </p> </li>
<li id="GUID-6A95E431-C203-5442-BDD8-AEF0FD19AE72"><p>Perform the actual parsing. </p> <p>Use
a <codeph>CParser</codeph> object as explained in <xref href="GUID-E16070E5-379A-5818-81CC-B00059A40084.dita">Choosing
a Parser Plug-in</xref>. To ensure that parsing is followed by validation
and autocorrection, associate the <codeph>CParser</codeph> object with the
plug-in chain. This can be done by calling <xref href="GUID-667DBD60-ABF3-326B-8FF9-86BC7DC7662F.dita"><apiname>SetProcessorChainL()</apiname></xref> function
of the <codeph>CParser</codeph> object with a list of the items in the plugin
chain as a parameter. </p> <p>The following code illustrates how to validate
and autocorrect the parsed document: </p> <codeblock id="GUID-39142F60-28D0-55FF-B9B3-DB5149638C2C" xml:space="preserve">RFs fs;
User::LeaveIfError( fs.Connect() );
CleanupClosePushL( fs );

_LIT8( KXmlMimeType, "text/xml" );
TSimpleContentHandler sax; // You’ll have to implement this class…

CParser* parser = CParser::NewLC( KXmlMimeType, sax );

RContentProcessorUids uids;
uids.Append( KValidatorUid ); // The ECOM implementation UID of a validator plug-in
CleanupClosePushL( uids );

// Sets up the chain of call-back events from the parser through to the
// validating plug-in and then the client.
parser-&gt;SetProcessorChainL( uids );

parser-&gt;ParseFileL( fs, KMyFile );

CleanupStack::PopAndDestroy( 3 );</codeblock> </li>
</ol> </section>
</conbody></concept>