AttributesImpl
is a default implementation of the
Attributes interface that SAX parsers and filters
may use. Besides the methods of the Attributes
interface, this class offers manipulator methods so the list of
attributes can be modified or reused. These methods allow you to take
a persistent snapshot of an Attributes object in
startElement( ) and construct or modify an
Attributes object in a SAX driver or filter:
package org.xml.sax.helpers;
public class AttributesImpl implements Attributes {
public AttributesImpl( );
public AttributesImpl(Attributes atts);
public int getLength( );
public String getURI(int index);
public String getLocalName(int index);
public String getQName(int index);
public String getType(int index);
public String getValue(int index);
public int getIndex(String uri, String localName);
public int getIndex(String qualifiedName);
public String getType(String uri, String localName);
public String getType(String qualifiedName);
public String getValue(String uri, String localName);
public String getValue(String qualifiedName);
public void clear( );
public void setAttributes(Attributes atts);
public void addAttribute(String uri, String localName,
String qualifiedName, String type, String value);
public void setAttribute(int index, String uri, String localName,
String qualifiedName, String type, String value);
public void removeAttribute(int index)
public void setURI(int index, String uri)
public void setLocalName(int index, String localName)
public void setQName(int index, String qualifiedName);
public void setType(int index, String type);
public void setValue(int index, String value);
}
DefaultHandler
is a convenience class that implements
the EntityResolver, DTDHandler,
ContentHandler, and
ErrorHandler interfaces with do-nothing methods.
You can subclass DefaultHandler and override
methods for events to which you actually want to respond. You never
have to use this class. You can always implement the interfaces
directly instead. The pattern is similar to the adapter classes in
the AWT, such as MouseAdapter and
WindowAdapter:
package org.xml.sax.helpers;
public class DefaultHandler
implements EntityResolver, DTDHandler, ContentHandler, ErrorHandler {
// Default implementation of the EntityResolver interface.
public InputSource resolveEntity(String publicID, String systemID)
throws SAXException {
return null;
}
// Default implementation of the DTDHandler interface.
public void notationDecl(String name, String publicID, String systemID)
throws SAXException {}
public void unparsedEntityDecl(String name, String publicID,
String systemID, String notationName) throws SAXException{}
// Default implementation of the ContentHandler interface.
public void setDocumentLocator(Locator locator) {}
public void startDocument( ) throws SAXException {}
public void endDocument( ) throws SAXException {}
public void startPrefixMapping(String prefix, String uri)
throws SAXException {}
public void endPrefixMapping(String prefix) throws SAXException {}
public void startElement(String uri, String localName,
String qualifiedName, Attributes attributes) throws SAXException {}
public void endElement(String uri, String localName,
String qualifiedName) throws SAXException {}
public void characters(char[] text, int start, int length)
throws SAXException {}
public void ignorableWhitespace(char[] whitespace, int start,
int length) throws SAXException {}
public void processingInstruction(String target, String data)
throws SAXException {}
public void skippedEntity(String name) throws SAXException {}
// Default implementation of the ErrorHandler interface.
public void warning(SAXParseException ex) throws SAXException {}
public void error(SAXParseException ex) throws SAXException {}
public void fatalError(SAXParseException ex) throws SAXException {
throw ex;
}
}
LocatorImpl is a
default implementation of the
Locator interface for the convenience of parser
writers. You probably won't need to use it directly.
Besides the constructors, it adds setter methods to set the public
ID, system ID, line number, and column number returned by the getter
methods declared in Locator:
package org.xml.sax.helpers;
public class LocatorImpl implements Locator {
public LocatorImpl( );
public LocatorImpl(Locator locator);
public String getPublicId( );
public String getSystemId( );
public int getLineNumber( );
public int getColumnNumber( );
public void setPublicId(String publicID);
public void setSystemId(String systemID);
public void setLineNumber(int lineNumber);
public void setColumnNumber(int columnNumber);
}
| The NamespaceSupport Class | |
NamespaceSupport
provides a stack that can track the namespaces in
scope at various points in the document. To use it, push a new
context at the beginning of each element's namespace
mappings, and place it at the end of each element. Each
startPrefixMapping( ) invocation should call
declarePrefix( ) to add a new mapping to the
NamespaceSupport object. Then at any point where
you need to figure out to which URI a prefix is bound, you can call
getPrefix( ). The empty string indicates the
default namespace. The getter methods can then tell you the prefix
that is mapped to any URI or the URI that is mapped to any prefix at
each point in the document. If you reuse the same
NamespaceSupport object for multiple documents, be
sure to call reset( ) in between documents.
package org.xml.sax.helpers;
public class NamespaceSupport {
public final static String XMLNS="http://www.w3.org/XML/1998/namespace";
public NamespaceSupport( );
public void reset( );
public void pushContext( );
public void popContext( );
public boolean declarePrefix(String prefix, String uri);
public String[] processName(String qualifiedName, String[] parts,
boolean isAttribute);
public String getURI(String prefix);
public Enumeration getPrefixes( );
public String getPrefix(String uri);
public Enumeration getPrefixes(String uri);
public Enumeration getDeclaredPrefixes( );
}
The ParserAdapter
class uses the adapter design pattern to convert
a SAX1 org.xml.sax.Parser object into a SAX2
org.xml.sax.XMLReader object. As more parsers
support SAX2, this class becomes less necessary. Note that some SAX2
features are not available through an adapted SAX1 parser. For
instance, a parser created with this adapter does not report skipped
entities and does not support most features and properties, not even
the core features and properties:
package org.xml.sax.helpers;
public class ParserAdapter implements XMLReader, DocumentHandler {
public ParserAdapter( ) throws SAXException;
public ParserAdapter(Parser parser);
// Implementation of org.xml.sax.XMLReader.
public void setFeature(String name, boolean state)
throws SAXNotRecognizedException, SAXNotSupportedException;
public boolean getFeature(String name)
throws SAXNotRecognizedException, SAXNotSupportedException;
public void setProperty(String name, Object value)
throws SAXNotRecognizedException, SAXNotSupportedException;
public Object getProperty(String name)
throws SAXNotRecognizedException, SAXNotSupportedException;
public void setEntityResolver(EntityResolver resolver);
public EntityResolver getEntityResolver( );
public void setDTDHandler(DTDHandler handler);
public DTDHandler getDTDHandler( );
public void setContentHandler(ContentHandler handler);
public ContentHandler getContentHandler( );
public void setErrorHandler(ErrorHandler handler);
public ErrorHandler getErrorHandler( );
public void parse(String systemID) throws IOException, SAXException;
public void parse(InputSource input) throws IOException, SAXException;
// Implementation of org.xml.sax.DocumentHandler.
public void setDocumentLocator(Locator locator);
public void startDocument( ) throws SAXException;
public void endDocument( ) throws SAXException;
public void startElement(String qualifiedName,
AttributeList qualifiedAttributes) throws SAXException;
public void endElement(String qualifiedName) throws SAXException;
public void characters(char[] text, int start, int length)
throws SAXException;
public void ignorableWhitespace(char[] text, int start, int length)
throws SAXException;
public void processingInstruction(String target, String data)
throws SAXException;
}
XMLFilterImpl
is invaluable for implementing
XML filters correctly. An
instance of this class sits between an XMLReader
and the client application's event handlers. It
receives messages from the reader and passes them to the application
unchanged, and vice versa. However, by subclassing this class and
overriding particular methods, you can change the events that are
sent before the application gets to see them. You chain a filter to
an XMLReader by passing the reader as an argument
to the filter's constructor. When parsing, you
invoke the filter's parse( )
method, not the reader's parse( )
method.
package org.xml.sax.helpers;
public class XMLFilterImpl implements XMLFilter, EntityResolver,
DTDHandler, ContentHandler, ErrorHandler {
public XMLFilterImpl( );
public XMLFilterImpl(XMLReader parent);
// Implementation of org.xml.sax.XMLFilter
public void setParent(XMLReader parent);
public XMLReader getParent( );
// Implementation of org.xml.sax.XMLReader
public void setFeature(String name, boolean state)
throws SAXNotRecognizedException, SAXNotSupportedException;
public boolean getFeature(String name)
throws SAXNotRecognizedException, SAXNotSupportedException;
public void setProperty(String name, Object value)
throws SAXNotRecognizedException, SAXNotSupportedException;
public Object getProperty(String name)
throws SAXNotRecognizedException, SAXNotSupportedException;
public void setEntityResolver(EntityResolver resolver);
public EntityResolver getEntityResolver( );
public void setDTDHandler(DTDHandler handler);
public DTDHandler getDTDHandler( );
public void setContentHandler(ContentHandler handler);
public ContentHandler getContentHandler( );
public void setErrorHandler(ErrorHandler handler);
public ErrorHandler getErrorHandler( );
public void parse(InputSource input) throws SAXException, IOException;
public void parse(String systemID) throws SAXException, IOException
// Implementation of org.xml.sax.EntityResolver
public InputSource resolveEntity(String publicID, String systemID)
throws SAXException, IOException;
// Implementation of org.xml.sax.DTDHandler
public void notationDecl(String name, String publicID, String systemID)
throws SAXException;
public void unparsedEntityDecl(String name, String publicID,
String systemID, String notationName) throws SAXException;
// Implementation of org.xml.sax.ContentHandler
public void setDocumentLocator(Locator locator);
public void startDocument( ) throws SAXException;
public void endDocument( ) throws SAXException;
public void startPrefixMapping(String prefix, String uri)
throws SAXException;
public void endPrefixMapping(String prefix) throws SAXException;
public void startElement(String namespaceURI, String localName,
String qualifiedName, Attributes atts) throws SAXException;
public void endElement(String namespaceURI, String localName,
String qualifiedName) throws SAXException;
public void characters(char[] text, int start, int length)
throws SAXException;
public void ignorableWhitespace(char[] text, int start, int length)
throws SAXException;
public void processingInstruction(String target, String data)
throws SAXException;
public void skippedEntity(String name) throws SAXException;
// Implementation of org.xml.sax.ErrorHandler
public void warning(SAXParseException ex) throws SAXException;
public void error(SAXParseException ex) throws SAXException;
public void fatalError(SAXParseException ex) throws SAXException;
}
| The XMLReaderAdapter Class | |
XMLReaderAdapter
is the reverse of
ParserAdapter; it uses the
Adapter design pattern to adapt a SAX2
XMLReader to a SAX1 Parser.
This lets you use SAX2 parsers for legacy programs written to a SAX1
interface:
package org.xml.sax.helpers;
public class XMLReaderAdapter implements Parser, ContentHandler {
public XMLReaderAdapter( ) throws SAXException;
public XMLReaderAdapter(XMLReader reader);
// Implementation of org.xml.sax.Parser.
public void setLocale(Locale locale) throws SAXException;
public void setEntityResolver(EntityResolver resolver);
public void setDTDHandler(DTDHandler handler);
public void setDocumentHandler(DocumentHandler handler);
public void setErrorHandler(ErrorHandler handler);
public void parse(String systemID) throws IOException, SAXException;
public void parse(InputSource input) throws IOException, SAXException
// Implementation of org.xml.sax.ContentHandler.
public void setDocumentLocator(Locator locator);
public void startDocument( ) throws SAXException;
public void endDocument( ) throws SAXException;
public void startPrefixMapping(String prefix, String uri)
throws SAXException;
public void endPrefixMapping(String prefix) throws SAXException;
public void startElement(String namespaceURI, String localName,
String qualifiedName, Attributes atts) throws SAXException;
public void endElement(String namespaceURI, String localName,
String qualifiedName) throws SAXException;
public void characters(char[] text, int start, int length)
throws SAXException;
public void ignorableWhitespace(char[] text, int start, int length)
throws SAXException;
public void processingInstruction(String target, String data)
throws SAXException;
public void skippedEntity(String name) throws SAXException;
}
| The XMLReaderFactory Class | |
XMLReaderFactory
creates XMLReader
instances in a parser-independent manner. The noargs
createXMLReader( )
method instantiates the class named by the
org.xml.sax.driver system property. The other
createXMLReader( ) method instantiates the class
named by its argument. This argument should be a fully packaged
qualified name, such as
org.apache.xerces.parsers.SAXParser:
package org.xml.sax.helpers;
public final class XMLReaderFactory {
public static XMLReader createXMLReader( ) throws SAXException;
public static XMLReader createXMLReader(String className)
throws SAXException;
}
