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nsISAXContentHandler

IID:2a99c757-dfee-4806-bff3-f721440412e0
Inherits From:nsISupports

Receive notification of the logical content of a document.

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. 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.

This interface is implemented by the following components:


Methods

void characters ( AString value ) void endDocument ( ) void endElement ( AString uri , AString localName , AString qName ) void endPrefixMapping ( AString prefix ) void ignorableWhitespace ( AString whitespace ) void processingInstruction ( AString target , AString data ) void startDocument ( ) void startElement ( AString uri , AString localName , AString qName , nsISAXAttributes attributes ) void startPrefixMapping ( AString prefix , AString uri )

void characters ( AString value )

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.

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

Arguments:
value: the characters from the XML document

void endDocument ( )

Receive notification of the end of a document.

There is an apparent contradiction between the documentation for this method and the documentation for ErrorHandler.fatalError(). Until this ambiguity is resolved in a future major release, clients should make no assumptions about whether endDocument() will or will not be invoked when the parser has reported a fatalError() or thrown an exception.

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.


void endElement ( AString uri , AString localName , AString qName )

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).

For information on the names, see startElement.

Arguments:
uri: the Namespace URI, or the empty string if the element has no Namespace URI or if Namespace processing is not being performed
localName: the local name (without prefix), or the empty string if Namespace processing is not being performed
qName: the qualified XML name (with prefix), or the empty string if qualified names are not available

void endPrefixMapping ( AString prefix )

End the scope of a prefix-URI mapping.

See startPrefixMapping for details. These events will always occur immediately after the corresponding endElement event, but the order of endPrefixMapping events is not otherwise guaranteed.

Arguments:
prefix: The prefix that was being mapped. This is the empty string when a default mapping scope ends.

void ignorableWhitespace ( AString whitespace )

Receive notification of ignorable whitespace in element content.

Validating Parsers must use this method to report each chunk of whitespace in element content (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.

Arguments:
whitespace: the characters from the XML document

void processingInstruction ( AString target , AString data )

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 must 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.

Arguments:
target: the processing instruction target
data: the processing instruction data, or null if none was supplied. The data does not include any whitespace separating it from the target

void startDocument ( )

Receive notification of the beginning of a document.

The SAX parser will invoke this method only once, before any other event callbacks.


void startElement ( AString uri , AString localName , AString qName , nsISAXAttributes attributes )

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.

This event allows up to three name components for each element:

1.) the Namespace URI; 2.) the local name; and 3.) the qualified (prefixed) name.

Any or all of these may be provided, depending on the values of the http://xml.org/sax/features/namespaces and the http://xml.org/sax/features/namespace-prefixes properties:

The Namespace URI and local name are required when the namespaces property is true (the default), and are optional when the namespaces property is false (if one is specified, both must be);

The qualified name is required when the namespace-prefixes property is true, and is optional when the namespace-prefixes property is false (the default).

Note that the attribute list provided will contain only attributes with explicit values (specified or defaulted): #IMPLIED attributes will be omitted. The attribute list will contain attributes used for Namespace declarations (xmlns* attributes) only if the http://xml.org/sax/features/namespace-prefixes property is true (it is false by default, and support for a true value is optional).

Arguments:
uri: the Namespace URI, or the empty string if the element has no Namespace URI or if Namespace processing is not being performed
localName: the local name (without prefix), or the empty string if Namespace processing is not being performed
qName: the qualified name (with prefix), or the empty string if qualified names are not available
attributes

void startPrefixMapping ( AString prefix , AString uri )

Begin the scope of a prefix-URI Namespace mapping.

The information from this event is not necessary for normal Namespace processing: the SAX XML reader will automatically replace prefixes for element and attribute names when the http://xml.org/sax/features/namespaces feature is true (the default).

There are cases, however, when applications need to use prefixes in character data or in attribute values, where they cannot safely be expanded automatically; the start/endPrefixMapping event supplies the information to the application to expand prefixes in those contexts itself, if necessary.

Note that start/endPrefixMapping events are not guaranteed to be properly nested relative to each other: all startPrefixMapping events will occur immediately before the corresponding startElement event, and all endPrefixMapping events will occur immediately after the corresponding endElement event, but their order is not otherwise guaranteed.

There should never be start/endPrefixMapping events for the "xml" prefix, since it is predeclared and immutable.

Arguments:
prefix: The Namespace prefix being declared. An empty string is used for the default element namespace, which has no prefix.
uri: The Namespace URI the prefix is mapped to.

References

This interface is the type of the following properties:

nsISAXXMLReader.contentHandler

Reference documentation is generated from Mozilla's source.