+ * 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 designed to sit between an {@link org.xml.sax.XMLReader + * XMLReader} and the client application's event handlers. By default, it + * does nothing but pass requests up to the reader and events + * on to the handlers unmodified, but subclasses can override + * specific methods to modify the event stream or the configuration + * requests as they pass through.
+ * + * @since 1.4, SAX 2.0 + * @author David Megginson + * @see org.xml.sax.XMLFilter + * @see org.xml.sax.XMLReader + * @see org.xml.sax.EntityResolver + * @see org.xml.sax.DTDHandler + * @see org.xml.sax.ContentHandler + * @see org.xml.sax.ErrorHandler + */ +public class XMLFilterImpl + implements XMLFilter, EntityResolver, DTDHandler, ContentHandler, ErrorHandler +{ + + + //////////////////////////////////////////////////////////////////// + // Constructors. + //////////////////////////////////////////////////////////////////// + + + /** + * Construct an empty XML filter, with no parent. + * + *This filter will have no parent: you must assign a parent + * before you start a parse or do any configuration with + * setFeature or setProperty, unless you use this as a pure event + * consumer rather than as an {@link XMLReader}.
+ * + * @see org.xml.sax.XMLReader#setFeature + * @see org.xml.sax.XMLReader#setProperty + * @see #setParent + */ + public XMLFilterImpl () + { + super(); + } + + + /** + * Construct an XML filter with the specified parent. + * + * @see #setParent + * @see #getParent + */ + public XMLFilterImpl (XMLReader parent) + { + super(); + setParent(parent); + } + + + + //////////////////////////////////////////////////////////////////// + // Implementation of org.xml.sax.XMLFilter. + //////////////////////////////////////////////////////////////////// + + + /** + * Set the parent reader. + * + *This is the {@link org.xml.sax.XMLReader XMLReader} from which + * this filter will obtain its events and to which it will pass its + * configuration requests. The parent may itself be another filter.
+ * + *If there is no parent reader set, any attempt to parse + * or to set or get a feature or property will fail.
+ * + * @param parent The parent XML reader. + * @see #getParent + */ + public void setParent (XMLReader parent) + { + this.parent = parent; + } + + + /** + * Get the parent reader. + * + * @return The parent XML reader, or null if none is set. + * @see #setParent + */ + public XMLReader getParent () + { + return parent; + } + + + + //////////////////////////////////////////////////////////////////// + // Implementation of org.xml.sax.XMLReader. + //////////////////////////////////////////////////////////////////// + + + /** + * Set the value of a feature. + * + *This will always fail if the parent is null.
+ * + * @param name The feature name. + * @param value The requested feature value. + * @exception org.xml.sax.SAXNotRecognizedException If the feature + * value can't be assigned or retrieved from the parent. + * @exception org.xml.sax.SAXNotSupportedException When the + * parent recognizes the feature name but + * cannot set the requested value. + */ + public void setFeature (String name, boolean value) + throws SAXNotRecognizedException, SAXNotSupportedException + { + if (parent != null) { + parent.setFeature(name, value); + } else { + throw new SAXNotRecognizedException("Feature: " + name); + } + } + + + /** + * Look up the value of a feature. + * + *This will always fail if the parent is null.
+ * + * @param name The feature name. + * @return The current value of the feature. + * @exception org.xml.sax.SAXNotRecognizedException If the feature + * value can't be assigned or retrieved from the parent. + * @exception org.xml.sax.SAXNotSupportedException When the + * parent recognizes the feature name but + * cannot determine its value at this time. + */ + public boolean getFeature (String name) + throws SAXNotRecognizedException, SAXNotSupportedException + { + if (parent != null) { + return parent.getFeature(name); + } else { + throw new SAXNotRecognizedException("Feature: " + name); + } + } + + + /** + * Set the value of a property. + * + *This will always fail if the parent is null.
+ * + * @param name The property name. + * @param value The requested property value. + * @exception org.xml.sax.SAXNotRecognizedException If the property + * value can't be assigned or retrieved from the parent. + * @exception org.xml.sax.SAXNotSupportedException When the + * parent recognizes the property name but + * cannot set the requested value. + */ + public void setProperty (String name, Object value) + throws SAXNotRecognizedException, SAXNotSupportedException + { + if (parent != null) { + parent.setProperty(name, value); + } else { + throw new SAXNotRecognizedException("Property: " + name); + } + } + + + /** + * Look up the value of a property. + * + * @param name The property name. + * @return The current value of the property. + * @exception org.xml.sax.SAXNotRecognizedException If the property + * value can't be assigned or retrieved from the parent. + * @exception org.xml.sax.SAXNotSupportedException When the + * parent recognizes the property name but + * cannot determine its value at this time. + */ + public Object getProperty (String name) + throws SAXNotRecognizedException, SAXNotSupportedException + { + if (parent != null) { + return parent.getProperty(name); + } else { + throw new SAXNotRecognizedException("Property: " + name); + } + } + + + /** + * Set the entity resolver. + * + * @param resolver The new entity resolver. + */ + public void setEntityResolver (EntityResolver resolver) + { + entityResolver = resolver; + } + + + /** + * Get the current entity resolver. + * + * @return The current entity resolver, or null if none was set. + */ + public EntityResolver getEntityResolver () + { + return entityResolver; + } + + + /** + * Set the DTD event handler. + * + * @param handler the new DTD handler + */ + public void setDTDHandler (DTDHandler handler) + { + dtdHandler = handler; + } + + + /** + * Get the current DTD event handler. + * + * @return The current DTD handler, or null if none was set. + */ + public DTDHandler getDTDHandler () + { + return dtdHandler; + } + + + /** + * Set the content event handler. + * + * @param handler the new content handler + */ + public void setContentHandler (ContentHandler handler) + { + contentHandler = handler; + } + + + /** + * Get the content event handler. + * + * @return The current content handler, or null if none was set. + */ + public ContentHandler getContentHandler () + { + return contentHandler; + } + + + /** + * Set the error event handler. + * + * @param handler the new error handler + */ + public void setErrorHandler (ErrorHandler handler) + { + errorHandler = handler; + } + + + /** + * Get the current error event handler. + * + * @return The current error handler, or null if none was set. + */ + public ErrorHandler getErrorHandler () + { + return errorHandler; + } + + + /** + * Parse a document. + * + * @param input The input source for the document entity. + * @exception org.xml.sax.SAXException Any SAX exception, possibly + * wrapping another exception. + * @exception java.io.IOException An IO exception from the parser, + * possibly from a byte stream or character stream + * supplied by the application. + */ + public void parse (InputSource input) + throws SAXException, IOException + { + setupParse(); + parent.parse(input); + } + + + /** + * Parse a document. + * + * @param systemId The system identifier as a fully-qualified URI. + * @exception org.xml.sax.SAXException Any SAX exception, possibly + * wrapping another exception. + * @exception java.io.IOException An IO exception from the parser, + * possibly from a byte stream or character stream + * supplied by the application. + */ + public void parse (String systemId) + throws SAXException, IOException + { + parse(new InputSource(systemId)); + } + + + + //////////////////////////////////////////////////////////////////// + // Implementation of org.xml.sax.EntityResolver. + //////////////////////////////////////////////////////////////////// + + + /** + * Filter an external entity resolution. + * + * @param publicId The entity's public identifier, or null. + * @param systemId The entity's system identifier. + * @return A new InputSource or null for the default. + * @exception org.xml.sax.SAXException The client may throw + * an exception during processing. + * @exception java.io.IOException The client may throw an + * I/O-related exception while obtaining the + * new InputSource. + */ + public InputSource resolveEntity (String publicId, String systemId) + throws SAXException, IOException + { + if (entityResolver != null) { + return entityResolver.resolveEntity(publicId, systemId); + } else { + return null; + } + } + + + + //////////////////////////////////////////////////////////////////// + // Implementation of org.xml.sax.DTDHandler. + //////////////////////////////////////////////////////////////////// + + + /** + * Filter a notation declaration event. + * + * @param name The notation name. + * @param publicId The notation's public identifier, or null. + * @param systemId The notation's system identifier, or null. + * @exception org.xml.sax.SAXException The client may throw + * an exception during processing. + */ + public void notationDecl (String name, String publicId, String systemId) + throws SAXException + { + if (dtdHandler != null) { + dtdHandler.notationDecl(name, publicId, systemId); + } + } + + + /** + * Filter an unparsed entity declaration event. + * + * @param name The entity name. + * @param publicId The entity's public identifier, or null. + * @param systemId The entity's system identifier, or null. + * @param notationName The name of the associated notation. + * @exception org.xml.sax.SAXException The client may throw + * an exception during processing. + */ + public void unparsedEntityDecl (String name, String publicId, + String systemId, String notationName) + throws SAXException + { + if (dtdHandler != null) { + dtdHandler.unparsedEntityDecl(name, publicId, systemId, + notationName); + } + } + + + + //////////////////////////////////////////////////////////////////// + // Implementation of org.xml.sax.ContentHandler. + //////////////////////////////////////////////////////////////////// + + + /** + * Filter a new document locator event. + * + * @param locator The document locator. + */ + public void setDocumentLocator (Locator locator) + { + this.locator = locator; + if (contentHandler != null) { + contentHandler.setDocumentLocator(locator); + } + } + + + /** + * Filter a start document event. + * + * @exception org.xml.sax.SAXException The client may throw + * an exception during processing. + */ + public void startDocument () + throws SAXException + { + if (contentHandler != null) { + contentHandler.startDocument(); + } + } + + + /** + * Filter an end document event. + * + * @exception org.xml.sax.SAXException The client may throw + * an exception during processing. + */ + public void endDocument () + throws SAXException + { + if (contentHandler != null) { + contentHandler.endDocument(); + } + } + + + /** + * Filter a start Namespace prefix mapping event. + * + * @param prefix The Namespace prefix. + * @param uri The Namespace URI. + * @exception org.xml.sax.SAXException The client may throw + * an exception during processing. + */ + public void startPrefixMapping (String prefix, String uri) + throws SAXException + { + if (contentHandler != null) { + contentHandler.startPrefixMapping(prefix, uri); + } + } + + + /** + * Filter an end Namespace prefix mapping event. + * + * @param prefix The Namespace prefix. + * @exception org.xml.sax.SAXException The client may throw + * an exception during processing. + */ + public void endPrefixMapping (String prefix) + throws SAXException + { + if (contentHandler != null) { + contentHandler.endPrefixMapping(prefix); + } + } + + + /** + * Filter a start element event. + * + * @param uri The element's Namespace URI, or the empty string. + * @param localName The element's local name, or the empty string. + * @param qName The element's qualified (prefixed) name, or the empty + * string. + * @param atts The element's attributes. + * @exception org.xml.sax.SAXException The client may throw + * an exception during processing. + */ + public void startElement (String uri, String localName, String qName, + Attributes atts) + throws SAXException + { + if (contentHandler != null) { + contentHandler.startElement(uri, localName, qName, atts); + } + } + + + /** + * Filter an end element event. + * + * @param uri The element's Namespace URI, or the empty string. + * @param localName The element's local name, or the empty string. + * @param qName The element's qualified (prefixed) name, or the empty + * string. + * @exception org.xml.sax.SAXException The client may throw + * an exception during processing. + */ + public void endElement (String uri, String localName, String qName) + throws SAXException + { + if (contentHandler != null) { + contentHandler.endElement(uri, localName, qName); + } + } + + + /** + * Filter a character data event. + * + * @param ch An array of characters. + * @param start The starting position in the array. + * @param length The number of characters to use from the array. + * @exception org.xml.sax.SAXException The client may throw + * an exception during processing. + */ + public void characters (char ch[], int start, int length) + throws SAXException + { + if (contentHandler != null) { + contentHandler.characters(ch, start, length); + } + } + + + /** + * Filter an ignorable whitespace event. + * + * @param ch An array of characters. + * @param start The starting position in the array. + * @param length The number of characters to use from the array. + * @exception org.xml.sax.SAXException The client may throw + * an exception during processing. + */ + public void ignorableWhitespace (char ch[], int start, int length) + throws SAXException + { + if (contentHandler != null) { + contentHandler.ignorableWhitespace(ch, start, length); + } + } + + + /** + * Filter a processing instruction event. + * + * @param target The processing instruction target. + * @param data The text following the target. + * @exception org.xml.sax.SAXException The client may throw + * an exception during processing. + */ + public void processingInstruction (String target, String data) + throws SAXException + { + if (contentHandler != null) { + contentHandler.processingInstruction(target, data); + } + } + + + /** + * Filter a skipped entity event. + * + * @param name The name of the skipped entity. + * @exception org.xml.sax.SAXException The client may throw + * an exception during processing. + */ + public void skippedEntity (String name) + throws SAXException + { + if (contentHandler != null) { + contentHandler.skippedEntity(name); + } + } + + + + //////////////////////////////////////////////////////////////////// + // Implementation of org.xml.sax.ErrorHandler. + //////////////////////////////////////////////////////////////////// + + + /** + * Filter a warning event. + * + * @param e The warning as an exception. + * @exception org.xml.sax.SAXException The client may throw + * an exception during processing. + */ + public void warning (SAXParseException e) + throws SAXException + { + if (errorHandler != null) { + errorHandler.warning(e); + } + } + + + /** + * Filter an error event. + * + * @param e The error as an exception. + * @exception org.xml.sax.SAXException The client may throw + * an exception during processing. + */ + public void error (SAXParseException e) + throws SAXException + { + if (errorHandler != null) { + errorHandler.error(e); + } + } + + + /** + * Filter a fatal error event. + * + * @param e The error as an exception. + * @exception org.xml.sax.SAXException The client may throw + * an exception during processing. + */ + public void fatalError (SAXParseException e) + throws SAXException + { + if (errorHandler != null) { + errorHandler.fatalError(e); + } + } + + + + //////////////////////////////////////////////////////////////////// + // Internal methods. + //////////////////////////////////////////////////////////////////// + + + /** + * Set up before a parse. + * + *Before every parse, check whether the parent is + * non-null, and re-register the filter for all of the + * events.
+ */ + private void setupParse () + { + if (parent == null) { + throw new NullPointerException("No parent for filter"); + } + parent.setEntityResolver(this); + parent.setDTDHandler(this); + parent.setContentHandler(this); + parent.setErrorHandler(this); + } + + + + //////////////////////////////////////////////////////////////////// + // Internal state. + //////////////////////////////////////////////////////////////////// + + private XMLReader parent = null; + private Locator locator = null; + private EntityResolver entityResolver = null; + private DTDHandler dtdHandler = null; + private ContentHandler contentHandler = null; + private ErrorHandler errorHandler = null; + +} + +// end of XMLFilterImpl.java