ContentHandler Class Reference

Receive notification of general document events. More...

Inheritance diagram for ContentHandler:

DefaultHandler

List of all members.

Public Member Functions

Constructors and Destructor
 ContentHandler ()
 Default constructor.
virtual ~ContentHandler ()
 Destructor.
The virtual document handler interface
virtual void characters (const XMLCh *const chars, const unsigned int length)=0
 Receive notification of character data.
virtual void endDocument ()=0
 Receive notification of the end of a document.
virtual void endElement (const XMLCh *const uri, const XMLCh *const localname, const XMLCh *const qname)=0
 Receive notification of the end of an element.
virtual void ignorableWhitespace (const XMLCh *const chars, const unsigned int length)=0
 Receive notification of ignorable whitespace in element content.
virtual void processingInstruction (const XMLCh *const target, const XMLCh *const data)=0
 Receive notification of a processing instruction.
virtual void setDocumentLocator (const Locator *const locator)=0
 Receive an object for locating the origin of SAX document events.
virtual void startDocument ()=0
 Receive notification of the beginning of a document.
virtual void startElement (const XMLCh *const uri, const XMLCh *const localname, const XMLCh *const qname, const Attributes &attrs)=0
 Receive notification of the beginning of an element.
virtual void startPrefixMapping (const XMLCh *const prefix, const XMLCh *const uri)=0
 Receive notification of the start of an namespace prefix mapping.
virtual void endPrefixMapping (const XMLCh *const prefix)=0
 Receive notification of the end of an namespace prefix mapping.
virtual void skippedEntity (const XMLCh *const name)=0
 Receive notification of a skipped entity.


Detailed Description

Receive notification of general document events.

This is the main interface that most SAX2 applications implement: if the application needs to be informed of basic parsing events, it implements this interface and registers an instance with the SAX2 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 Sax2HandlerBase, which implements the default functionality; parser writers can instantiate Sax2HandlerBase 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

Sax2HandlerBase::Sax2HandlerBase


Constructor & Destructor Documentation

ContentHandler::ContentHandler (  ) 

Default constructor.

virtual ContentHandler::~ContentHandler (  )  [virtual]

Destructor.


Member Function Documentation

virtual void ContentHandler::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

Implemented in DefaultHandler.

virtual void ContentHandler::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.

Implemented in DefaultHandler.

virtual void ContentHandler::endElement ( const XMLCh *const   uri,
const XMLCh *const   localname,
const XMLCh *const   qname 
) [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).

Parameters:
uri The URI of the asscioated namespace for this element
localname The local part of the element name
qname The QName of this element
Exceptions:
SAXException Any SAX exception, possibly wrapping another exception.

Implemented in DefaultHandler.

virtual void ContentHandler::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

Implemented in DefaultHandler.

virtual void ContentHandler::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.

Implemented in DefaultHandler.

virtual void ContentHandler::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

Implemented in DefaultHandler.

virtual void ContentHandler::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.

Implemented in DefaultHandler.

virtual void ContentHandler::startElement ( const XMLCh *const   uri,
const XMLCh *const   localname,
const XMLCh *const   qname,
const Attributes attrs 
) [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.

Note that the attribute list provided will contain only attributes with explicit values (specified or defaulted): IMPLIED attributes will be omitted.

Parameters:
uri The URI of the asscioated namespace for this element
localname The local part of the element name
qname The QName of this element
attrs The attributes attached to the element, if any.
Exceptions:
SAXException Any SAX exception, possibly wrapping another exception.
See also:
endElement

Attributes::Attributes

Implemented in DefaultHandler.

virtual void ContentHandler::startPrefixMapping ( const XMLCh *const   prefix,
const XMLCh *const   uri 
) [pure virtual]

Receive notification of the start of an namespace prefix mapping.

By default, do nothing. Application writers may override this method in a subclass to take specific actions at the start of each namespace prefix mapping.

Parameters:
prefix The namespace prefix used
uri The namespace URI used.
Exceptions:
SAXException Any SAX exception, possibly wrapping another exception.

Implemented in DefaultHandler.

virtual void ContentHandler::endPrefixMapping ( const XMLCh *const   prefix  )  [pure virtual]

Receive notification of the end of an namespace prefix mapping.

By default, do nothing. Application writers may override this method in a subclass to take specific actions at the end of each namespace prefix mapping.

Parameters:
prefix The namespace prefix used
Exceptions:
SAXException Any SAX exception, possibly wrapping another exception.

Implemented in DefaultHandler.

virtual void ContentHandler::skippedEntity ( const XMLCh *const   name  )  [pure virtual]

Receive notification of a skipped entity.

The parser will invoke this method once for each entity skipped. All processors may skip external entities, depending on the values of the features:
http://xml.org/sax/features/external-general-entities
http://xml.org/sax/features/external-parameter-entities

Note: Xerces (specifically) never skips any entities, regardless of the above features. This function is never called in the Xerces implementation of SAX2.

Introduced with SAX2

Parameters:
name The name of the skipped entity. If it is a parameter entity, the name will begin with %, and if it is the external DTD subset, it will be the string [dtd].
Exceptions:
SAXException Any SAX exception, possibly wrapping another exception.

Implemented in DefaultHandler.


The documentation for this class was generated from the following file:
Generated on Thu Feb 19 11:35:44 2009 for Xerces-C++ by  doxygen 1.5.4