public class XmlParser extends org.xml.sax.helpers.DefaultHandler implements WireFormatParser
XmlParser
.
The plan is to integrate it tighter with the WireFormatParser
interface, remove unnecessary interfaces and parameters (in our new
data model, there is only one XmlParser.ElementHandler
),
and move it away from the util package.
Existing data classes continue to use the old XML parser until they've been migrated to the new data model, at which point they will start to use the new 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(Element)
method.
XmlParser.ElementHandler
Modifier and Type | Field and Description |
---|---|
protected java.util.Map<java.lang.String,java.util.Stack<com.google.gdata.wireformats.XmlParser.NamespaceDecl>> |
namespaceMap
Set of all namespace declarations valid at the current location.
|
protected StreamProperties |
props
Input properties for parsing
|
protected java.lang.String |
rootElementName
Root element name.
|
protected com.google.gdata.wireformats.XmlParser.ElementHandler |
rootHandler
Root element handler.
|
protected java.lang.String |
rootNamespace
Root element namespace URI.
|
Constructor and Description |
---|
XmlParser(StreamProperties props,
java.io.Reader r,
java.nio.charset.Charset cs)
Construct XML parser for given reader.
|
XmlParser(StreamProperties props,
XmlEventSource eventSource)
Construct XML parser for a given event source.
|
Modifier and Type | Method and Description |
---|---|
void |
characters(char[] text,
int start,
int len)
SAX callback.
|
protected XmlHandler |
createRootHandler(ValidationContext vc,
Element element,
ElementMetadata<?,?> metadata)
Create the xml handler for the root element.
|
void |
endElement(java.lang.String namespace,
java.lang.String localName,
java.lang.String qName)
SAX callback.
|
void |
endPrefixMapping(java.lang.String alias)
SAX callback.
|
void |
ignorableWhitespace(char[] text,
int start,
int len)
SAX callback.
|
Element |
parse(Element element)
Parse content from a source provided to the parser at
construction time.
|
void |
setDocumentLocator(org.xml.sax.Locator newLocator)
SAX callback.
|
void |
startElement(java.lang.String namespace,
java.lang.String localName,
java.lang.String qName,
org.xml.sax.Attributes attrs)
SAX callback.
|
void |
startPrefixMapping(java.lang.String alias,
java.lang.String uri)
SAX callback.
|
protected void |
throwParseException(ParseException e)
Throws a parse exception with line/column information.
|
protected final StreamProperties props
protected com.google.gdata.wireformats.XmlParser.ElementHandler rootHandler
protected java.lang.String rootNamespace
protected java.lang.String rootElementName
protected java.util.Map<java.lang.String,java.util.Stack<com.google.gdata.wireformats.XmlParser.NamespaceDecl>> namespaceMap
public XmlParser(StreamProperties props, java.io.Reader r, java.nio.charset.Charset cs)
props
- stream properties for parsingr
- reader where input is retrieved fromcs
- character set used to encode inputpublic XmlParser(StreamProperties props, XmlEventSource eventSource)
props
- stream properties for parsingeventSource
- event sourcepublic Element parse(Element element) throws java.io.IOException, ParseException, ContentValidationException
WireFormatParser
parse
in interface WireFormatParser
element
- root of parsed element treejava.io.IOException
- if content cannot be accessedParseException
- if content cannot be parsed invalidContentValidationException
- if content fails metadata validationprotected XmlHandler createRootHandler(ValidationContext vc, Element element, ElementMetadata<?,?> metadata)
protected void throwParseException(ParseException e) throws ParseException
ParseException
public void startElement(java.lang.String namespace, java.lang.String localName, java.lang.String qName, org.xml.sax.Attributes attrs) throws org.xml.sax.SAXException
startElement
in interface org.xml.sax.ContentHandler
startElement
in class org.xml.sax.helpers.DefaultHandler
org.xml.sax.SAXException
public void endElement(java.lang.String namespace, java.lang.String localName, java.lang.String qName) throws org.xml.sax.SAXException
endElement
in interface org.xml.sax.ContentHandler
endElement
in class org.xml.sax.helpers.DefaultHandler
org.xml.sax.SAXException
public void characters(char[] text, int start, int len) throws org.xml.sax.SAXException
characters
in interface org.xml.sax.ContentHandler
characters
in class org.xml.sax.helpers.DefaultHandler
org.xml.sax.SAXException
public void ignorableWhitespace(char[] text, int start, int len) throws org.xml.sax.SAXException
ignorableWhitespace
in interface org.xml.sax.ContentHandler
ignorableWhitespace
in class org.xml.sax.helpers.DefaultHandler
org.xml.sax.SAXException
public void setDocumentLocator(org.xml.sax.Locator newLocator)
setDocumentLocator
in interface org.xml.sax.ContentHandler
setDocumentLocator
in class org.xml.sax.helpers.DefaultHandler
public void startPrefixMapping(java.lang.String alias, java.lang.String uri)
startPrefixMapping
in interface org.xml.sax.ContentHandler
startPrefixMapping
in class org.xml.sax.helpers.DefaultHandler
public void endPrefixMapping(java.lang.String alias)
endPrefixMapping
in interface org.xml.sax.ContentHandler
endPrefixMapping
in class org.xml.sax.helpers.DefaultHandler