xmlfilterbase.java

JAVA的Jdom包

     * with character data content, including the start tag
     * and end tag.  This method provides an empty string
     * for the qname and an empty attribute list. It invokes
     * {@link #dataElement(String, String, String, Attributes, String)}}
     * directly.</p>
     *
     * @param uri The element's Namespace URI.
     * @param localName The element's local name.
     * @param content The character data content.
     * @exception org.xml.sax.SAXException If a filter
     *            further down the chain raises an exception.
     * @see org.xml.sax.ContentHandler#startElement
     * @see #characters(String)
     * @see org.xml.sax.ContentHandler#endElement
     */
    public void dataElement (String uri, String localName, String content)
    throws SAXException
    {
        dataElement(uri, localName, "", EMPTY_ATTS, content);
    }


    /**
     * Add an element with character data content but no Namespace URI or qname.
     *
     * <p>This is a convenience method to add a complete element
     * with character data content, including the start tag
     * and end tag.  The method provides an empty string for the
     * Namespace URI, and empty string for the qualified name. It invokes
     * {@link #dataElement(String, String, String, Attributes, String)}}
     * directly.</p>
     *
     * @param localName The element's local name.
     * @param atts The element's attributes.
     * @param content The character data content.
     * @exception org.xml.sax.SAXException If a filter
     *            further down the chain raises an exception.
     * @see org.xml.sax.ContentHandler#startElement
     * @see #characters(String)
     * @see org.xml.sax.ContentHandler#endElement
     */
    public void dataElement (String localName, Attributes atts, String content)
    throws SAXException
    {
        dataElement("", localName, "", atts, content);
    }


    /**
     * Add an element with character data content but no attributes
     * or Namespace URI.
     *
     * <p>This is a convenience method to add a complete element
     * with character data content, including the start tag
     * and end tag.  The method provides an empty string for the
     * Namespace URI, and empty string for the qualified name,
     * and an empty attribute list. It invokes
     * {@link #dataElement(String, String, String, Attributes, String)}}
     * directly.</p>
     *
     * @param localName The element's local name.
     * @param content The character data content.
     * @exception org.xml.sax.SAXException If a filter
     *            further down the chain raises an exception.
     * @see org.xml.sax.ContentHandler#startElement
     * @see #characters(String)
     * @see org.xml.sax.ContentHandler#endElement
     */
    public void dataElement (String localName, String content)
    throws SAXException
    {
        dataElement("", localName, "", EMPTY_ATTS, content);
    }


    /**
     * Add a string of character data, with XML escaping.
     *
     * <p>This is a convenience method that takes an XML
     * String, converts it to a character array, then invokes
     * {@link @see org.xml.sax.ContentHandler#characters}.</p>
     *
     * @param data The character data.
     * @exception org.xml.sax.SAXException If a filter
     *            further down the chain raises an exception.
     * @see @see org.xml.sax.ContentHandler#characters
     */
    public void characters (String data)
    throws SAXException
    {
        char ch[] = data.toCharArray();
        characters(ch, 0, ch.length);
    }



    ////////////////////////////////////////////////////////////////////
    // Override org.xml.sax.helpers.XMLFilterImpl methods.
    ////////////////////////////////////////////////////////////////////


    /**
     * Set the value of a property.
     *
     * <p>This will always fail if the parent is null.</p>
     *
     * @param name The property name.
     * @param state The requested property value.
     * @exception org.xml.sax.SAXNotRecognizedException When the
     *            XMLReader does not recognize the property name.
     * @exception org.xml.sax.SAXNotSupportedException When the
     *            XMLReader recognizes the property name but
     *            cannot set the requested value.
     * @see org.xml.sax.XMLReader#setProperty
     */
    public void setProperty (String name, Object value)
    throws SAXNotRecognizedException, SAXNotSupportedException
    {
        for (int i = 0; i < LEXICAL_HANDLER_NAMES.length; i++) {
            if (LEXICAL_HANDLER_NAMES[i].equals(name)) {
                setLexicalHandler((LexicalHandler) value);
                return;
            }
        }
        super.setProperty(name, value);
    }
    
    
    /**
     * Look up the value of a property.
     *
     * @param name The property name.
     * @return The current value of the property.
     * @exception org.xml.sax.SAXNotRecognizedException When the
     *            XMLReader does not recognize the feature name.
     * @exception org.xml.sax.SAXNotSupportedException When the
     *            XMLReader recognizes the property name but
     *            cannot determine its value at this time.
     * @see org.xml.sax.XMLReader#setFeature
     */
    public Object getProperty (String name)
    throws SAXNotRecognizedException, SAXNotSupportedException
    {
        for (int i = 0; i < LEXICAL_HANDLER_NAMES.length; i++) {
            if (LEXICAL_HANDLER_NAMES[i].equals(name)) {
                return getLexicalHandler();
            }
        }
        return super.getProperty(name);
    }


    /**
     * 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.
     * @see org.xml.sax.XMLReader#parse(org.xml.sax.InputSource)
     */
    public void parse (InputSource input)
    throws SAXException, IOException
    {
        installLexicalHandler();
        super.parse(input);
    }



    ////////////////////////////////////////////////////////////////////
    // Registration of org.xml.sax.ext.LexicalHandler.
    ////////////////////////////////////////////////////////////////////


    /**
     * Set the lexical handler.
     *
     * @param handler The new lexical handler.
     * @exception java.lang.NullPointerException If the handler
     *            is null.
     */
    public void setLexicalHandler (LexicalHandler handler)
    {
        if (handler == null) {
            throw new NullPointerException("Null lexical handler");
        } else {
            lexicalHandler = handler;
        }
    }
    
    
    /**
     * Get the current lexical handler.
     *
     * @return The current lexical handler, or null if none was set.
     */
    public LexicalHandler getLexicalHandler ()
    {
        return lexicalHandler;
    }



    ////////////////////////////////////////////////////////////////////
    // Implementation of org.xml.sax.ext.LexicalHandler.
    ////////////////////////////////////////////////////////////////////


    /**
     * Filter a start DTD event.
     *
     * @param name The document type name.
     * @param publicId The declared public identifier for the
     *        external DTD subset, or null if none was declared.
     * @param systemId The declared system identifier for the
     *        external DTD subset, or null if none was declared.
     * @exception org.xml.sax.SAXException If a filter
     *            further down the chain raises an exception.
     * @see org.xml.sax.ext.LexicalHandler#startDTD
     */
    public void startDTD(String name, String publicId, String systemId)
    throws SAXException {
        if (lexicalHandler != null) {
            lexicalHandler.startDTD(name, publicId, systemId);
        }
    }


    /**
     * Filter a end DTD event.
     *
     * @exception org.xml.sax.SAXException If a filter
     *            further down the chain raises an exception.
     * @see org.xml.sax.ext.LexicalHandler#endDTD
     */
    public void endDTD()
    throws SAXException {
        if (lexicalHandler != null) {
            lexicalHandler.endDTD();
        }
    }    


    /*
     * Filter a start entity event.
     *
     * @param name The name of the entity.  If it is a parameter
     *        entity, the name will begin with '%', and if it is the
     *        external DTD subset, it will be "[dtd]".
     * @exception org.xml.sax.SAXException If a filter
     *            further down the chain raises an exception.
     * @see org.xml.sax.ext.LexicalHandler#startEntity
     */
    public void startEntity(String name)
    throws SAXException {
        if (lexicalHandler != null) {
            lexicalHandler.startEntity(name);
        }
    }


    /*
     * Filter a end entity event.
     *
     * @param name The name of the entity that is ending.
     * @exception org.xml.sax.SAXException If a filter
     *            further down the chain raises an exception.
     * @see org.xml.sax.ext.LexicalHandler#endEntity
     */
    public void endEntity(String name)
    throws SAXException {
        if (lexicalHandler != null) {
            lexicalHandler.endEntity(name);
        }
    }


    /*
     * Filter a start CDATA event.
     *
     * @exception org.xml.sax.SAXException If a filter
     *            further down the chain raises an exception.
     * @see org.xml.sax.ext.LexicalHandler#startCDATA
     */
    public void startCDATA()
    throws SAXException {
        if (lexicalHandler != null) {
            lexicalHandler.startCDATA();
        }
    }    


    /*
     * Filter a end CDATA event.
     *
     * @exception org.xml.sax.SAXException If a filter
     *            further down the chain raises an exception.
     * @see org.xml.sax.ext.LexicalHandler#endCDATA
     */
    public void endCDATA()
    throws SAXException {
        if (lexicalHandler != null) {
            lexicalHandler.endCDATA();
        }
    }


    /*
     * Filter a comment event.
     *
     * @param ch An array holding the characters in the comment.
     * @param start The starting position in the array.
     * @param length The number of characters to use from the array.
     * @exception org.xml.sax.SAXException If a filter
     *            further down the chain raises an exception.
     * @see org.xml.sax.ext.LexicalHandler#comment
     */
    public void comment(char[] ch, int start, int length)
    throws SAXException {
        if (lexicalHandler != null) {
            lexicalHandler.comment(ch, start, length);
        }
    }



    ////////////////////////////////////////////////////////////////////
    // Internal methods.
    ////////////////////////////////////////////////////////////////////


    /**
     * Installs lexical handler before a parse.
     *
     * <p>Before every parse, check whether the parent is
     * non-null, and re-register the filter for the lexical
     * events.</p>
     */
    private void installLexicalHandler ()
    {
        XMLReader parent = getParent();
        if (parent == null) {
            throw new NullPointerException("No parent for filter");
        }
        // try to register for lexical events
        for (int i = 0; i < LEXICAL_HANDLER_NAMES.length; i++) {
            try {
                parent.setProperty(LEXICAL_HANDLER_NAMES[i], this);
                break;
            }
            catch (SAXNotRecognizedException ex) {
                // ignore
            }
            catch (SAXNotSupportedException ex) {
                // ignore
            }
        }
    }



    ////////////////////////////////////////////////////////////////////
    // Internal state.
    ////////////////////////////////////////////////////////////////////


    private LexicalHandler lexicalHandler = null;



    ////////////////////////////////////////////////////////////////////
    // Constants.
    ////////////////////////////////////////////////////////////////////


    protected static final Attributes EMPTY_ATTS = new AttributesImpl();

    protected static final String[] LEXICAL_HANDLER_NAMES = {
        "http://xml.org/sax/properties/lexical-handler",
        "http://xml.org/sax/handlers/LexicalHandler"
    };


}

// end of XMLFilterBase.java