Xerces-C++: DocumentHandler Class Reference

Xerces-C++ 3.3.0

List of all members
DocumentHandler Class Referenceabstract

Receive notification of general document events. More...

`#include <xercesc/sax/DocumentHandler.hpp>`

Inheritance diagram for DocumentHandler:

## Public Member Functions
Constructors and Destructor
| DocumentHandler ()
| Default constructor.
virtual | ~DocumentHandler ()
| Destructor.

## The virtual document handler interface
virtual void | characters (const XMLCh *const chars, const XMLSize_t 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 name)=0
| Receive notification of the end of an element.
virtual void | ignorableWhitespace (const XMLCh *const chars, const XMLSize_t 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 | resetDocument ()=0
| Reset the Document object on its reuse.
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 name, AttributeList &attrs)=0
| Receive notification of the beginning of an element.

## 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::DocumentHandler | ( |  | ) |

Default constructor.

## ◆ ~DocumentHandler()

virtual DocumentHandler::~DocumentHandler | ( |  | ) |
| virtual

Destructor.

## Member Function Documentation

## ◆ characters()

virtual void DocumentHandler::characters | ( | const XMLCh *const | chars,
|  | const XMLSize_t | 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 HandlerBase.

## ◆ endDocument()

virtual 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.

Implemented in HandlerBase.

## ◆ endElement()

virtual 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.

Implemented in HandlerBase.

## ◆ ignorableWhitespace()

virtual void DocumentHandler::ignorableWhitespace | ( | const XMLCh *const | chars,
|  | const XMLSize_t | 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 HandlerBase.

## ◆ processingInstruction()

virtual 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.

Implemented in HandlerBase.

## ◆ resetDocument()

virtual void DocumentHandler::resetDocument | ( |  | ) |
| pure virtual

Reset the Document object on its reuse.

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

Implemented in HandlerBase.

## ◆ setDocumentLocator()

virtual 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

Implemented in HandlerBase.

## ◆ startDocument()

virtual 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.

Implemented in HandlerBase.

## ◆ startElement()

virtual void DocumentHandler::startElement | ( | const XMLCh *const | name,
|  | AttributeList & | 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.

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

Implemented in HandlerBase.

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

- DocumentHandler.hpp