QXmlReader Class

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# QXmlReader Class Reference
[XML module]

The QXmlReader class provides an interface for XML readers (i.e. parsers). More...

All the functions in this class are reentrant when Qt is built with thread support.

`#include <qxml.h>`

Inherited by QXmlSimpleReader.

List of all member functions.

## Public Members

- virtual bool feature ( const QString & name, bool * ok = 0 ) const = 0
- virtual void setFeature ( const QString & name, bool value ) = 0
- virtual bool hasFeature ( const QString & name ) const = 0
- virtual void * property ( const QString & name, bool * ok = 0 ) const = 0
- virtual void setProperty ( const QString & name, void * value ) = 0
- virtual bool hasProperty ( const QString & name ) const = 0
- virtual void setEntityResolver ( QXmlEntityResolver * handler ) = 0
- virtual QXmlEntityResolver * entityResolver () const = 0
- virtual void setDTDHandler ( QXmlDTDHandler * handler ) = 0
- virtual QXmlDTDHandler * DTDHandler () const = 0
- virtual void setContentHandler ( QXmlContentHandler * handler ) = 0
- virtual QXmlContentHandler * contentHandler () const = 0
- virtual void setErrorHandler ( QXmlErrorHandler * handler ) = 0
- virtual QXmlErrorHandler * errorHandler () const = 0
- virtual void setLexicalHandler ( QXmlLexicalHandler * handler ) = 0
- virtual QXmlLexicalHandler * lexicalHandler () const = 0
- virtual void setDeclHandler ( QXmlDeclHandler * handler ) = 0
- virtual QXmlDeclHandler * declHandler () const = 0
- virtual bool parse ( const QXmlInputSource & input ) = 0 (obsolete)
- virtual bool parse ( const QXmlInputSource * input ) = 0

## Detailed Description

The QXmlReader class provides an interface for XML readers (i.e. parsers).

This abstract class provides an interface for all of Qt's XML readers. Currently there is only one implementation of a reader included in Qt's XML module: QXmlSimpleReader. In future releases there might be more readers with different properties available (e.g. a validating parser).

The design of the XML classes follows the SAX2 Java interface, with the names adapted to fit Qt naming conventions. It should be very easy for anybody who has worked with SAX2 to get started with the Qt XML classes.

All readers use the class QXmlInputSource to read the input document. Since you are normally interested in particular content in the XML document, the reader reports the content through special handler classes (QXmlDTDHandler, QXmlDeclHandler, QXmlContentHandler, QXmlEntityResolver, QXmlErrorHandler and QXmlLexicalHandler), which you must subclass, if you want to process the contents.

Since the handler classes only describe interfaces you must implement all the functions. We provide the QXmlDefaultHandler class to make this easier: it implements a default behaviour (do nothing) for all functions, so you can subclass it and just implement the functions you are interested in.

Features and properties of the reader can be set with setFeature() and setProperty() respectively. You can set the reader to use your own subclasses with setEntityResolver(), setDTDHandler(), setContentHandler(), setErrorHandler(), setLexicalHandler() and setDeclHandler(). The parse itself is started with a call to parse().

See also QXmlSimpleReader and XML.

## Member Function Documentation

### QXmlDTDHandler * QXmlReader::DTDHandler () const`[pure virtual]`

Returns the DTD handler or 0 if none was set.

See also setDTDHandler().

### QXmlContentHandler * QXmlReader::contentHandler () const`[pure virtual]`

Returns the content handler or 0 if none was set.

See also setContentHandler().

### QXmlDeclHandler * QXmlReader::declHandler () const`[pure virtual]`

Returns the declaration handler or 0 if none was set.

See also setDeclHandler().

### QXmlEntityResolver * QXmlReader::entityResolver () const`[pure virtual]`

Returns the entity resolver or 0 if none was set.

See also setEntityResolver().

### QXmlErrorHandler * QXmlReader::errorHandler () const`[pure virtual]`

Returns the error handler or 0 if none is set.

See also setErrorHandler().

### bool QXmlReader::feature ( const QString & name, bool * ok = 0 ) const`[pure virtual]`

If the reader has the feature called name, the feature's value is returned. If no such feature exists the return value is undefined.

If ok is not 0: *ok is set to TRUE if the reader has the feature called name; otherwise *ok is set to FALSE.

See also setFeature() and hasFeature().

### bool QXmlReader::hasFeature ( const QString & name ) const`[pure virtual]`

Returns `TRUE` if the reader has the feature called name; otherwise returns FALSE.

See also feature() and setFeature().

### bool QXmlReader::hasProperty ( const QString & name ) const`[pure virtual]`

Returns TRUE if the reader has the property name; otherwise returns FALSE.

See also property() and setProperty().

### QXmlLexicalHandler * QXmlReader::lexicalHandler () const`[pure virtual]`

Returns the lexical handler or 0 if none was set.

See also setLexicalHandler().

### bool QXmlReader::parse ( const QXmlInputSource * input )`[pure virtual]`

Reads an XML document from input and parses it. Returns TRUE if the parsing was successful; otherwise returns FALSE.

Example: xml/tagreader/tagreader.cpp.

### bool QXmlReader::parse ( const QXmlInputSource & input )`[pure virtual]`

This function is obsolete. It is provided to keep old source working. We strongly advise against using it in new code.

### void * QXmlReader::property ( const QString & name, bool * ok = 0 ) const`[pure virtual]`

If the reader has the property name, this function returns the value of the property; otherwise the return value is undefined.

If ok is not 0: if the reader has the name property *ok is set to TRUE; otherwise *ok is set to FALSE.

See also setProperty() and hasProperty().

### void QXmlReader::setContentHandler ( QXmlContentHandler * handler )`[pure virtual]`

Sets the content handler to handler.

See also contentHandler().

Example: xml/tagreader/tagreader.cpp.

### void QXmlReader::setDTDHandler ( QXmlDTDHandler * handler )`[pure virtual]`

Sets the DTD handler to handler.

See also DTDHandler().

### void QXmlReader::setDeclHandler ( QXmlDeclHandler * handler )`[pure virtual]`

Sets the declaration handler to handler.

See also declHandler().

### void QXmlReader::setEntityResolver ( QXmlEntityResolver * handler )`[pure virtual]`

Sets the entity resolver to handler.

See also entityResolver().

### void QXmlReader::setErrorHandler ( QXmlErrorHandler * handler )`[pure virtual]`

Sets the error handler to handler. Clears the error handler if handler is 0.

See also errorHandler().

### void QXmlReader::setFeature ( const QString & name, bool value )`[pure virtual]`

Sets the feature called name to the given value. If the reader doesn't have the feature nothing happens.

See also feature() and hasFeature().

Reimplemented in QXmlSimpleReader.

### void QXmlReader::setLexicalHandler ( QXmlLexicalHandler * handler )`[pure virtual]`

Sets the lexical handler to handler.

See also lexicalHandler().

### void QXmlReader::setProperty ( const QString & name, void * value )`[pure virtual]`

Sets the property name to value. If the reader doesn't have the property nothing happens.

See also property() and hasProperty().

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