+ * This module, both source code and documentation, is in the + * Public Domain, and comes with NO WARRANTY. + * See http://www.saxproject.org + * for further information. + *+ * + *
This class is available as a convenience base class for SAX2 + * applications: it provides default implementations for all of the + * callbacks in the four core SAX2 handler classes:
+ * + *Application writers can extend this class when they need to + * implement only part of an interface; parser writers can + * instantiate this class to provide default handlers when the + * application has not supplied its own.
+ * + *This class replaces the deprecated SAX1 + * {@link org.xml.sax.HandlerBase HandlerBase} class.
+ * + * @since SAX 2.0 + * @author David Megginson, + * @see org.xml.sax.EntityResolver + * @see org.xml.sax.DTDHandler + * @see org.xml.sax.ContentHandler + * @see org.xml.sax.ErrorHandler + */ +public class DefaultHandler + implements EntityResolver, DTDHandler, ContentHandler, ErrorHandler +{ + + + //////////////////////////////////////////////////////////////////// + // Default implementation of the EntityResolver interface. + //////////////////////////////////////////////////////////////////// + + /** + * Resolve an external entity. + * + *Always return null, so that the parser will use the system + * identifier provided in the XML document. This method implements + * the SAX default behaviour: application writers can override it + * in a subclass to do special translations such as catalog lookups + * or URI redirection.
+ * + * @param publicId The public identifier, or null if none is + * available. + * @param systemId The system identifier provided in the XML + * document. + * @return The new input source, or null to require the + * default behaviour. + * @exception java.io.IOException If there is an error setting + * up the new input source. + * @exception org.xml.sax.SAXException Any SAX exception, possibly + * wrapping another exception. + * @see org.xml.sax.EntityResolver#resolveEntity + */ + public InputSource resolveEntity (String publicId, String systemId) + throws IOException, SAXException + { + return null; + } + + + + //////////////////////////////////////////////////////////////////// + // Default implementation of DTDHandler interface. + //////////////////////////////////////////////////////////////////// + + + /** + * Receive notification of a notation declaration. + * + *By default, do nothing. Application writers may override this + * method in a subclass if they wish to keep track of the notations + * declared in a document.
+ * + * @param name The notation name. + * @param publicId The notation public identifier, or null if not + * available. + * @param systemId The notation system identifier. + * @exception org.xml.sax.SAXException Any SAX exception, possibly + * wrapping another exception. + * @see org.xml.sax.DTDHandler#notationDecl + */ + public void notationDecl (String name, String publicId, String systemId) + throws SAXException + { + // no op + } + + + /** + * Receive notification of an unparsed entity declaration. + * + *By default, do nothing. Application writers may override this + * method in a subclass to keep track of the unparsed entities + * declared in a document.
+ * + * @param name The entity name. + * @param publicId The entity public identifier, or null if not + * available. + * @param systemId The entity system identifier. + * @param notationName The name of the associated notation. + * @exception org.xml.sax.SAXException Any SAX exception, possibly + * wrapping another exception. + * @see org.xml.sax.DTDHandler#unparsedEntityDecl + */ + public void unparsedEntityDecl (String name, String publicId, + String systemId, String notationName) + throws SAXException + { + // no op + } + + + + //////////////////////////////////////////////////////////////////// + // Default implementation of ContentHandler interface. + //////////////////////////////////////////////////////////////////// + + + /** + * Receive a Locator object for document events. + * + *By default, do nothing. Application writers may override this + * method in a subclass if they wish to store the locator for use + * with other document events.
+ * + * @param locator A locator for all SAX document events. + * @see org.xml.sax.ContentHandler#setDocumentLocator + * @see org.xml.sax.Locator + */ + public void setDocumentLocator (Locator locator) + { + // no op + } + + + /** + * Receive notification of the beginning of the document. + * + *By default, do nothing. Application writers may override this + * method in a subclass to take specific actions at the beginning + * of a document (such as allocating the root node of a tree or + * creating an output file).
+ * + * @exception org.xml.sax.SAXException Any SAX exception, possibly + * wrapping another exception. + * @see org.xml.sax.ContentHandler#startDocument + */ + public void startDocument () + throws SAXException + { + // no op + } + + + /** + * Receive notification of the end of the document. + * + *By default, do nothing. Application writers may override this + * method in a subclass to take specific actions at the end + * of a document (such as finalising a tree or closing an output + * file).
+ * + * @exception org.xml.sax.SAXException Any SAX exception, possibly + * wrapping another exception. + * @see org.xml.sax.ContentHandler#endDocument + */ + public void endDocument () + throws SAXException + { + // no op + } + + + /** + * Receive notification of the start of a Namespace mapping. + * + *By default, do nothing. Application writers may override this + * method in a subclass to take specific actions at the start of + * each Namespace prefix scope (such as storing the prefix mapping).
+ * + * @param prefix The Namespace prefix being declared. + * @param uri The Namespace URI mapped to the prefix. + * @exception org.xml.sax.SAXException Any SAX exception, possibly + * wrapping another exception. + * @see org.xml.sax.ContentHandler#startPrefixMapping + */ + public void startPrefixMapping (String prefix, String uri) + throws SAXException + { + // no op + } + + + /** + * Receive notification of the end of a Namespace mapping. + * + *By default, do nothing. Application writers may override this + * method in a subclass to take specific actions at the end of + * each prefix mapping.
+ * + * @param prefix The Namespace prefix being declared. + * @exception org.xml.sax.SAXException Any SAX exception, possibly + * wrapping another exception. + * @see org.xml.sax.ContentHandler#endPrefixMapping + */ + public void endPrefixMapping (String prefix) + throws SAXException + { + // no op + } + + + /** + * Receive notification of the start of an element. + * + *By default, do nothing. Application writers may override this + * method in a subclass to take specific actions at the start of + * each element (such as allocating a new tree node or writing + * output to a file).
+ * + * @param uri The Namespace URI, or the empty string if the + * element has no Namespace URI or if Namespace + * processing is not being performed. + * @param localName The local name (without prefix), or the + * empty string if Namespace processing is not being + * performed. + * @param qName The qualified name (with prefix), or the + * empty string if qualified names are not available. + * @param attributes The attributes attached to the element. If + * there are no attributes, it shall be an empty + * Attributes object. + * @exception org.xml.sax.SAXException Any SAX exception, possibly + * wrapping another exception. + * @see org.xml.sax.ContentHandler#startElement + */ + public void startElement (String uri, String localName, + String qName, Attributes attributes) + throws SAXException + { + // no op + } + + + /** + * Receive notification of the end of an element. + * + *By default, do nothing. Application writers may override this + * method in a subclass to take specific actions at the end of + * each element (such as finalising a tree node or writing + * output to a file).
+ * + * @param uri The Namespace URI, or the empty string if the + * element has no Namespace URI or if Namespace + * processing is not being performed. + * @param localName The local name (without prefix), or the + * empty string if Namespace processing is not being + * performed. + * @param qName The qualified name (with prefix), or the + * empty string if qualified names are not available. + * @exception org.xml.sax.SAXException Any SAX exception, possibly + * wrapping another exception. + * @see org.xml.sax.ContentHandler#endElement + */ + public void endElement (String uri, String localName, String qName) + throws SAXException + { + // no op + } + + + /** + * Receive notification of character data inside an element. + * + *By default, do nothing. Application writers may override this + * method to take specific actions for each chunk of character data + * (such as adding the data to a node or buffer, or printing it to + * a file).
+ * + * @param ch The characters. + * @param start The start position in the character array. + * @param length The number of characters to use from the + * character array. + * @exception org.xml.sax.SAXException Any SAX exception, possibly + * wrapping another exception. + * @see org.xml.sax.ContentHandler#characters + */ + public void characters (char ch[], int start, int length) + throws SAXException + { + // no op + } + + + /** + * Receive notification of ignorable whitespace in element content. + * + *By default, do nothing. Application writers may override this + * method to take specific actions for each chunk of ignorable + * whitespace (such as adding data to a node or buffer, or printing + * it to a file).
+ * + * @param ch The whitespace characters. + * @param start The start position in the character array. + * @param length The number of characters to use from the + * character array. + * @exception org.xml.sax.SAXException Any SAX exception, possibly + * wrapping another exception. + * @see org.xml.sax.ContentHandler#ignorableWhitespace + */ + public void ignorableWhitespace (char ch[], int start, int length) + throws SAXException + { + // no op + } + + + /** + * Receive notification of a processing instruction. + * + *By default, do nothing. Application writers may override this + * method in a subclass to take specific actions for each + * processing instruction, such as setting status variables or + * invoking other methods.
+ * + * @param target The processing instruction target. + * @param data The processing instruction data, or null if + * none is supplied. + * @exception org.xml.sax.SAXException Any SAX exception, possibly + * wrapping another exception. + * @see org.xml.sax.ContentHandler#processingInstruction + */ + public void processingInstruction (String target, String data) + throws SAXException + { + // no op + } + + + /** + * Receive notification of a skipped entity. + * + *By default, do nothing. Application writers may override this + * method in a subclass to take specific actions for each + * processing instruction, such as setting status variables or + * invoking other methods.
+ * + * @param name The name of the skipped entity. + * @exception org.xml.sax.SAXException Any SAX exception, possibly + * wrapping another exception. + * @see org.xml.sax.ContentHandler#processingInstruction + */ + public void skippedEntity (String name) + throws SAXException + { + // no op + } + + + + //////////////////////////////////////////////////////////////////// + // Default implementation of the ErrorHandler interface. + //////////////////////////////////////////////////////////////////// + + + /** + * Receive notification of a parser warning. + * + *The default implementation does nothing. Application writers + * may override this method in a subclass to take specific actions + * for each warning, such as inserting the message in a log file or + * printing it to the console.
+ * + * @param e The warning information encoded as an exception. + * @exception org.xml.sax.SAXException Any SAX exception, possibly + * wrapping another exception. + * @see org.xml.sax.ErrorHandler#warning + * @see org.xml.sax.SAXParseException + */ + public void warning (SAXParseException e) + throws SAXException + { + // no op + } + + + /** + * Receive notification of a recoverable parser error. + * + *The default implementation does nothing. Application writers + * may override this method in a subclass to take specific actions + * for each error, such as inserting the message in a log file or + * printing it to the console.
+ * + * @param e The error information encoded as an exception. + * @exception org.xml.sax.SAXException Any SAX exception, possibly + * wrapping another exception. + * @see org.xml.sax.ErrorHandler#warning + * @see org.xml.sax.SAXParseException + */ + public void error (SAXParseException e) + throws SAXException + { + // no op + } + + + /** + * Report a fatal XML parsing error. + * + *The default implementation throws a SAXParseException. + * Application writers may override this method in a subclass if + * they need to take specific actions for each fatal error (such as + * collecting all of the errors into a single report): in any case, + * the application must stop all regular processing when this + * method is invoked, since the document is no longer reliable, and + * the parser may no longer report parsing events.
+ * + * @param e The error information encoded as an exception. + * @exception org.xml.sax.SAXException Any SAX exception, possibly + * wrapping another exception. + * @see org.xml.sax.ErrorHandler#fatalError + * @see org.xml.sax.SAXParseException + */ + public void fatalError (SAXParseException e) + throws SAXException + { + throw e; + } + +} + +// end of DefaultHandler.java