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DocumentHandler Class Reference

Receive notification of general document events. More...

#include <DocumentHandler.hpp>

Inheritance diagram for DocumentHandler

Inheritance graph
[legend]
List of all members.

Public Methods

Constructors and Destructor
 DocumentHandler ()
 Default constructor.

virtual ~DocumentHandler ()
 Destructor.

The virtual document handler interface
virtual void characters ( const XMLCh* const chars , const unsigned int length ) = 0
 Receive notification of character data. More...

virtual void endDocument () = 0
 Receive notification of the end of a document. More...

virtual void endElement (const XMLCh* const name) = 0
 Receive notification of the end of an element. More...

virtual void ignorableWhitespace ( const XMLCh* const chars , const unsigned int length ) = 0
 Receive notification of ignorable whitespace in element content. More...

virtual void processingInstruction ( const XMLCh* const target , const XMLCh* const data ) = 0
 Receive notification of a processing instruction. More...

virtual void resetDocument () = 0
 Reset the Docuemnt object on its reuse. More...

virtual void setDocumentLocator (const Locator* const locator) = 0
 Receive an object for locating the origin of SAX document events. More...

virtual void startDocument () = 0
 Receive notification of the beginning of a document. More...

virtual void startElement ( const XMLCh* const name , AttributeList& attrs ) = 0
 Receive notification of the beginning of an element. More...


Detailed Description

Receive notification of general document events.

This is the main interface that most SAX applications implement: if the application needs to be informed of basic parsing events, it implements this interface and registers an instance with the SAX parser using the setDocumentHandler method. The parser uses the instance to report basic document-related events like the start and end of elements and character data.

The order of events in this interface is very important, and mirrors the order of information in the document itself. For example, all of an element's content (character data, processing instructions, and/or subelements) will appear, in order, between the startElement event and the corresponding endElement event.

Application writers who do not want to implement the entire interface while can derive a class from HandlerBase, which implements the default functionality; parser writers can instantiate HandlerBase to obtain a default handler. The application can find the location of any document event using the Locator interface supplied by the Parser through the setDocumentLocator method.

See also:
Parser::setDocumentHandler , Locator::Locator , HandlerBase::HandlerBase


Constructor & Destructor Documentation

DocumentHandler::DocumentHandler ( )
 

Default constructor.

DocumentHandler::~DocumentHandler ( ) [virtual]
 

Destructor.


Member Function Documentation

void DocumentHandler::characters ( const XMLCh *const chars,
const unsigned int length ) [pure virtual]
 

Receive notification of character data.

The Parser will call this method to report each chunk of character data. SAX parsers may return all contiguous character data in a single chunk, or they may split it into several chunks; however, all of the characters in any single event must come from the same external entity, so that the Locator provides useful information.

The application must not attempt to read from the array outside of the specified range.

Note that some parsers will report whitespace using the ignorableWhitespace() method rather than this one (validating parsers must do so).

Parameters:
chars   The characters from the XML document.
length   The number of characters to read from the array.
Exceptions:
SAXException   Any SAX exception, possibly wrapping another exception.
See also:
ignorableWhitespace , Locator::Locator

Reimplemented in HandlerBase.

void DocumentHandler::endDocument ( ) [pure virtual]
 

Receive notification of the end of a document.

The SAX parser will invoke this method only once, and it will be the last method invoked during the parse. The parser shall not invoke this method until it has either abandoned parsing (because of an unrecoverable error) or reached the end of input.

Exceptions:
SAXException   Any SAX exception, possibly wrapping another exception.

Reimplemented in HandlerBase.

void DocumentHandler::endElement ( const XMLCh *const name ) [pure virtual]
 

Receive notification of the end of an element.

The SAX parser will invoke this method at the end of every element in the XML document; there will be a corresponding startElement() event for every endElement() event (even when the element is empty).

If the element name has a namespace prefix, the prefix will still be attached to the name.

Parameters:
name   The element type name
Exceptions:
SAXException   Any SAX exception, possibly wrapping another exception.

Reimplemented in HandlerBase.

void DocumentHandler::ignorableWhitespace ( const XMLCh *const chars,
const unsigned int length ) [pure virtual]
 

Receive notification of ignorable whitespace in element content.

Validating Parsers must use this method to report each chunk of ignorable whitespace (see the W3C XML 1.0 recommendation, section 2.10): non-validating parsers may also use this method if they are capable of parsing and using content models.

SAX parsers may return all contiguous whitespace in a single chunk, or they may split it into several chunks; however, all of the characters in any single event must come from the same external entity, so that the Locator provides useful information.

The application must not attempt to read from the array outside of the specified range.

Parameters:
chars   The characters from the XML document.
length   The number of characters to read from the array.
Exceptions:
SAXException   Any SAX exception, possibly wrapping another exception.
See also:
characters

Reimplemented in HandlerBase.

void DocumentHandler::processingInstruction ( const XMLCh *const target,
const XMLCh *const data ) [pure virtual]
 

Receive notification of a processing instruction.

The Parser will invoke this method once for each processing instruction found: note that processing instructions may occur before or after the main document element.

A SAX parser should never report an XML declaration (XML 1.0, section 2.8) or a text declaration (XML 1.0, section 4.3.1) using this method.

Parameters:
target   The processing instruction target.
data   The processing instruction data, or null if none was supplied.
Exceptions:
SAXException   Any SAX exception, possibly wrapping another exception.

Reimplemented in HandlerBase.

void DocumentHandler::resetDocument ( ) [pure virtual]
 

Reset the Docuemnt object on its reuse.

This method helps in reseting the document implementational defaults each time the document is begun.

Reimplemented in HandlerBase.

void DocumentHandler::setDocumentLocator ( const Locator *const locator ) [pure virtual]
 

Receive an object for locating the origin of SAX document events.

SAX parsers are strongly encouraged (though not absolutely required) to supply a locator: if it does so, it must supply the locator to the application by invoking this method before invoking any of the other methods in the DocumentHandler interface.

The locator allows the application to determine the end position of any document-related event, even if the parser is not reporting an error. Typically, the application will use this information for reporting its own errors (such as character content that does not match an application's business rules). The information returned by the locator is probably not sufficient for use with a search engine.

Note that the locator will return correct information only during the invocation of the events in this interface. The application should not attempt to use it at any other time.

Parameters:
locator   An object that can return the location of any SAX document event. The object is only 'on loan' to the client code and they are not to attempt to delete or modify it in any way!

See also:
Locator::Locator

Reimplemented in HandlerBase.

void DocumentHandler::startDocument ( ) [pure virtual]
 

Receive notification of the beginning of a document.

The SAX parser will invoke this method only once, before any other methods in this interface or in DTDHandler (except for setDocumentLocator).

Exceptions:
SAXException   Any SAX exception, possibly wrapping another exception.

Reimplemented in HandlerBase.

void DocumentHandler::startElement ( const XMLCh *const name,
AttributeList & attributes ) [pure virtual]
 

Receive notification of the beginning of an element.

The Parser will invoke this method at the beginning of every element in the XML document; there will be a corresponding endElement() event for every startElement() event (even when the element is empty). All of the element's content will be reported, in order, before the corresponding endElement() event.

If the element name has a namespace prefix, the prefix will still be attached. Note that the attribute list provided will contain only attributes with explicit values (specified or defaulted): IMPLIED attributes will be omitted.

Parameters:
name   The element type name.
attrs   The attributes attached to the element, if any.
Exceptions:
SAXException   Any SAX exception, possibly wrapping another exception.
See also:
endElement , AttributeList::AttributeList

Reimplemented in HandlerBase.


The documentation for this class was generated from the following file:


Copyright © 2000 The Apache Software Foundation. All Rights Reserved.