com.google.gdata.util

Class XmlParser

java.lang.Object

org.xml.sax.helpers.DefaultHandler

com.google.gdata.util.XmlParser

All Implemented Interfaces:

ContentHandler, DTDHandler, EntityResolver, ErrorHandler

Direct Known Subclasses:

EventSourceParser

public class XmlParser
extends org.xml.sax.helpers.DefaultHandler

XML parser.

This is a thin layer on top of a SAX parser. The key concept necessary to understand this parser is Element Handler. Element handlers are type-specific parsers. Each handler instance contains an instance of the Java type corresponding to the XML type it parses. At any given time, one handler is active, and zero or more handlers are kept on the stack. This corresponds directly to the set of currently opened XML tags.

To use this parser, one must define an XmlParser.ElementHandler type (usually one per XML schema type), specify the root element handler, and pass a reader to the parse(Reader, com.google.gdata.util.XmlParser.ElementHandler, String, String) method.

See Also:

XmlParser.ElementHandler

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	XmlParser.ElementHandler Base class for custom element handlers.

Field Summary

Fields

Modifier and Type	Field and Description
protected HashMap<String,Stack<com.google.gdata.util.XmlParser.NamespaceDecl>>	namespaceMap Set of all namespace declarations valid at the current location.
protected String	rootElementName Root element name.
protected XmlParser.ElementHandler	rootHandler Root element handler.
protected String	rootNamespace Root element namespace URI.

Constructor Summary

Constructors

Constructor and Description
XmlParser()

Method Summary

Methods

Modifier and Type	Method and Description
void	characters(char[] text, int start, int len) SAX callback.
void	endElement(String namespace, String localName, String qName) SAX callback.
void	endPrefixMapping(String alias) SAX callback.
void	ignorableWhitespace(char[] text, int start, int len) SAX callback.
protected void	parse(InputSource is) Parses XML.
void	parse(InputStream input, XmlParser.ElementHandler rootHandler, String rootNamespace, String rootElementName) Parses XML.
void	parse(Reader reader, XmlParser.ElementHandler rootHandler, String rootNamespace, String rootElementName) Parses XML.
void	parse(XmlParser.ElementHandler rootHandler, String rootNamespace, String rootElementName) Parses XML from a content source provided to the parser at construction time.
void	setDocumentLocator(Locator locator) SAX callback.
void	startElement(String namespace, String localName, String qName, Attributes attrs) SAX callback.
void	startPrefixMapping(String alias, String uri) SAX callback.
protected void	throwParseException(ParseException e) Throws a parse exception with line/column information.

Methods inherited from class org.xml.sax.helpers.DefaultHandler

endDocument, error, fatalError, notationDecl, processingInstruction, resolveEntity, skippedEntity, startDocument, unparsedEntityDecl, warning

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

rootHandler

protected XmlParser.ElementHandler rootHandler

Root element handler.

rootNamespace

protected String rootNamespace

Root element namespace URI.

rootElementName

protected String rootElementName

Root element name.

namespaceMap

protected HashMap<String,Stack<com.google.gdata.util.XmlParser.NamespaceDecl>> namespaceMap

Set of all namespace declarations valid at the current location. Includes namespace declarations from all ancestor elements.

Constructor Detail

XmlParser

public XmlParser()

Method Detail

parse

public void parse(Reader reader,
         XmlParser.ElementHandler rootHandler,
         String rootNamespace,
         String rootElementName)
           throws IOException,
                  ParseException

Parses XML.

Parameters:

reader - Supplies the XML to parse.

rootHandler - The root element handler corresponding to the expected document type.

rootNamespace - Root element namespace URI.

rootElementName - Root element name.

Throws:

IOException - Thrown by reader.

ParseException - XML failed to validate against the schema implemented by rootHandler.

parse

public void parse(InputStream input,
         XmlParser.ElementHandler rootHandler,
         String rootNamespace,
         String rootElementName)
           throws IOException,
                  ParseException

Parses XML.

Parameters:

input - Supplies the XML to parse.

rootHandler - The root element handler corresponding to the expected document type.

rootNamespace - Root element namespace URI.

rootElementName - Root element name.

Throws:

IOException - Thrown by input.

ParseException - XML failed to validate against the schema implemented by rootHandler.

parse

public void parse(XmlParser.ElementHandler rootHandler,
         String rootNamespace,
         String rootElementName)
           throws IOException,
                  ParseException

Parses XML from a content source provided to the parser at construction time.

Parameters:

rootHandler - The root element handler corresponding to the expected document type.

rootNamespace - Root element namespace URI.

rootElementName - Root element name.

Throws:

IOException - Thrown by reader.

ParseException - XML failed to validate against the schema implemented by rootHandler.

parse

protected void parse(InputSource is)
              throws IOException,
                     ParseException

Parses XML.

Parameters:

is - Supplies the XML to parse.

Throws:

IOException - Thrown by is.

ParseException - XML failed to validate against the schema implemented by rootHandler.

throwParseException

protected void throwParseException(ParseException e)
                            throws ParseException

Throws a parse exception with line/column information.

Throws:

ParseException

startElement

public void startElement(String namespace,
                String localName,
                String qName,
                Attributes attrs)
                  throws SAXException

SAX callback.

Specified by:

startElement in interface ContentHandler

Overrides:

startElement in class org.xml.sax.helpers.DefaultHandler

Throws:

SAXException

endElement

public void endElement(String namespace,
              String localName,
              String qName)
                throws SAXException

SAX callback.

Specified by:

endElement in interface ContentHandler

Overrides:

endElement in class org.xml.sax.helpers.DefaultHandler

Throws:

SAXException

characters

public void characters(char[] text,
              int start,
              int len)
                throws SAXException

SAX callback.

Specified by:

characters in interface ContentHandler

Overrides:

characters in class org.xml.sax.helpers.DefaultHandler

Throws:

SAXException

ignorableWhitespace

public void ignorableWhitespace(char[] text,
                       int start,
                       int len)
                         throws SAXException

SAX callback.

Specified by:

ignorableWhitespace in interface ContentHandler

Overrides:

ignorableWhitespace in class org.xml.sax.helpers.DefaultHandler

Throws:

SAXException

setDocumentLocator

public void setDocumentLocator(Locator locator)

SAX callback.

Specified by:

setDocumentLocator in interface ContentHandler

Overrides:

setDocumentLocator in class org.xml.sax.helpers.DefaultHandler

startPrefixMapping

public void startPrefixMapping(String alias,
                      String uri)

SAX callback.

Specified by:

startPrefixMapping in interface ContentHandler

Overrides:

startPrefixMapping in class org.xml.sax.helpers.DefaultHandler

endPrefixMapping

public void endPrefixMapping(String alias)

SAX callback.

Specified by:

endPrefixMapping in interface ContentHandler

Overrides:

endPrefixMapping in class org.xml.sax.helpers.DefaultHandler