parser.java

java1.6众多例子参考

		ErrorMsg err = new ErrorMsg(ErrorMsg.CLASS_NOT_FOUND_ERR, node);
		reportError(ERROR, err);
	    }
	    catch (Exception e) {
		ErrorMsg err = new ErrorMsg(ErrorMsg.INTERNAL_ERR,
					    e.getMessage(), node);
		reportError(FATAL, err);
	    }
	}
	else {
	    if (uri != null) {
		// Check if the element belongs in our namespace
		if (uri.equals(XSLT_URI)) {
		    node = new UnsupportedElement(uri, prefix, local, false);
		    UnsupportedElement element = (UnsupportedElement)node;
		    ErrorMsg msg = new ErrorMsg(ErrorMsg.UNSUPPORTED_XSL_ERR,
						getLineNumber(),local);
		    element.setErrorMessage(msg);
		    if (versionIsOne) {
		    	reportError(UNSUPPORTED,msg);
 		    }
		}
		// Check if this is an XSLTC extension element
		else if (uri.equals(TRANSLET_URI)) {
		    node = new UnsupportedElement(uri, prefix, local, true);
		    UnsupportedElement element = (UnsupportedElement)node;
		    ErrorMsg msg = new ErrorMsg(ErrorMsg.UNSUPPORTED_EXT_ERR,
						getLineNumber(),local);
		    element.setErrorMessage(msg);
		}
		// Check if this is an extension of some other XSLT processor
		else {
		    Stylesheet sheet = _xsltc.getStylesheet();
		    if ((sheet != null) && (sheet.isExtension(uri))) {
			if (sheet != (SyntaxTreeNode)_parentStack.peek()) {
			    node = new UnsupportedElement(uri, prefix, local, true);
			    UnsupportedElement elem = (UnsupportedElement)node;
			    ErrorMsg msg =
				new ErrorMsg(ErrorMsg.UNSUPPORTED_EXT_ERR,
					     getLineNumber(),
					     prefix+":"+local);
			    elem.setErrorMessage(msg);
			}
		    }
		}
	    }
	    if (node == null) {
                node = new LiteralElement();
                node.setLineNumber(getLineNumber());
            }
	}
	if ((node != null) && (node instanceof LiteralElement)) {
	    ((LiteralElement)node).setQName(qname);
	}
	return(node);
    }

    /**
     * checks the list of attributes against a list of allowed attributes
     * for a particular element node.
     */
    private void checkForSuperfluousAttributes(SyntaxTreeNode node, 
	Attributes attrs)
    {
	QName qname = node.getQName();
	boolean isStylesheet = (node instanceof Stylesheet); 
        String[] legal = (String[]) _instructionAttrs.get(qname);
	if (versionIsOne && legal != null) {
	    int j;
	    final int n = attrs.getLength();

	    for (int i = 0; i < n; i++) {
	        final String attrQName = attrs.getQName(i);

	        if (isStylesheet && attrQName.equals("version")) {
	            versionIsOne = attrs.getValue(i).equals("1.0");
	        }

		// Ignore if special or if it has a prefix
	        if (attrQName.startsWith("xml") ||
		    attrQName.indexOf(':') > 0) continue;

	        for (j = 0; j < legal.length; j++) {
	            if (attrQName.equalsIgnoreCase(legal[j])) {
		        break;
		    }	
	        }
	        if (j == legal.length) {
	            final ErrorMsg err = 
		        new ErrorMsg(ErrorMsg.ILLEGAL_ATTRIBUTE_ERR, 
				attrQName, node);
		    // Workaround for the TCK failure ErrorListener.errorTests.error001..
	            err.setWarningError(true);
		    reportError(WARNING, err);
	        }
	    }
        }	
    }


    /**
     * Parse an XPath expression:
     *  @param parent - XSL element where the expression occured
     *  @param exp    - textual representation of the expression
     */
    public Expression parseExpression(SyntaxTreeNode parent, String exp) {
	return (Expression)parseTopLevel(parent, "<EXPRESSION>"+exp, null);
    }

    /**
     * Parse an XPath expression:
     *  @param parent - XSL element where the expression occured
     *  @param attr   - name of this element's attribute to get expression from
     *  @param def    - default expression (if the attribute was not found)
     */
    public Expression parseExpression(SyntaxTreeNode parent,
				      String attr, String def) {
	// Get the textual representation of the expression (if any)
        String exp = parent.getAttribute(attr);
	// Use the default expression if none was found
        if ((exp.length() == 0) && (def != null)) exp = def;
	// Invoke the XPath parser
        return (Expression)parseTopLevel(parent, "<EXPRESSION>"+exp, exp);
    }

    /**
     * Parse an XPath pattern:
     *  @param parent  - XSL element where the pattern occured
     *  @param pattern - textual representation of the pattern
     */
    public Pattern parsePattern(SyntaxTreeNode parent, String pattern) {
	return (Pattern)parseTopLevel(parent, "<PATTERN>"+pattern, pattern);
    }

    /**
     * Parse an XPath pattern:
     *  @param parent - XSL element where the pattern occured
     *  @param attr   - name of this element's attribute to get pattern from
     *  @param def    - default pattern (if the attribute was not found)
     */
    public Pattern parsePattern(SyntaxTreeNode parent,
				String attr, String def) {
	// Get the textual representation of the pattern (if any)
        String pattern = parent.getAttribute(attr);
	// Use the default pattern if none was found
	if ((pattern.length() == 0) && (def != null)) pattern = def;
	// Invoke the XPath parser
        return (Pattern)parseTopLevel(parent, "<PATTERN>"+pattern, pattern);
    }

    /**
     * Parse an XPath expression or pattern using the generated XPathParser
     * The method will return a Dummy node if the XPath parser fails.
     */
    private SyntaxTreeNode parseTopLevel(SyntaxTreeNode parent, String text,
					 String expression) {
	int line = getLineNumber();

	try {
	    _xpathParser.setScanner(new XPathLexer(new StringReader(text)));
	    Symbol result = _xpathParser.parse(expression, line);
	    if (result != null) {
		final SyntaxTreeNode node = (SyntaxTreeNode)result.value;
		if (node != null) {
		    node.setParser(this);
		    node.setParent(parent);
		    node.setLineNumber(line);
// System.out.println("e = " + text + " " + node);
		    return node;
		}
	    } 
	    reportError(ERROR, new ErrorMsg(ErrorMsg.XPATH_PARSER_ERR,
					    expression, parent));
	}
	catch (Exception e) {
	    if (_xsltc.debug()) e.printStackTrace();
	    reportError(ERROR, new ErrorMsg(ErrorMsg.XPATH_PARSER_ERR,
					    expression, parent));
	}

	// Return a dummy pattern (which is an expression)
	SyntaxTreeNode.Dummy.setParser(this);
        return SyntaxTreeNode.Dummy; 
    }

    /************************ ERROR HANDLING SECTION ************************/

    /**
     * Returns true if there were any errors during compilation
     */
    public boolean errorsFound() {
	return _errors.size() > 0;
    }

    /**
     * Prints all compile-time errors
     */
    public void printErrors() {
	final int size = _errors.size();
	if (size > 0) {
	    System.err.println(new ErrorMsg(ErrorMsg.COMPILER_ERROR_KEY));
	    for (int i = 0; i < size; i++) {
		System.err.println("  " + _errors.elementAt(i));
	    }
	}
    }

    /**
     * Prints all compile-time warnings
     */
    public void printWarnings() {
	final int size = _warnings.size();
	if (size > 0) {
	    System.err.println(new ErrorMsg(ErrorMsg.COMPILER_WARNING_KEY));
	    for (int i = 0; i < size; i++) {
		System.err.println("  " + _warnings.elementAt(i));
	    }
	}
    }

    /**
     * Common error/warning message handler
     */
    public void reportError(final int category, final ErrorMsg error) {
	switch (category) {
	case Constants.INTERNAL:
	    // Unexpected internal errors, such as null-ptr exceptions, etc.
	    // Immediately terminates compilation, no translet produced
	    _errors.addElement(error);
	    break;
	case Constants.UNSUPPORTED:
	    // XSLT elements that are not implemented and unsupported ext.
	    // Immediately terminates compilation, no translet produced
	    _errors.addElement(error);
	    break;
	case Constants.FATAL:
	    // Fatal error in the stylesheet input (parsing or content)
	    // Immediately terminates compilation, no translet produced
	    _errors.addElement(error);
	    break;
	case Constants.ERROR:
	    // Other error in the stylesheet input (parsing or content)
	    // Does not terminate compilation, no translet produced
	    _errors.addElement(error);
	    break;
	case Constants.WARNING:
	    // Other error in the stylesheet input (content errors only)
	    // Does not terminate compilation, a translet is produced
	    _warnings.addElement(error);
	    break;
	}
    }

    public Vector getErrors() {
	return _errors;
    }

    public Vector getWarnings() {
	return _warnings;
    }

    /************************ SAX2 ContentHandler INTERFACE *****************/

    private Stack _parentStack = null;
    private Hashtable _prefixMapping = null;

    /**
     * SAX2: Receive notification of the beginning of a document.
     */
    public void startDocument() {
	_root = null;
	_target = null;
	_prefixMapping = null;
	_parentStack = new Stack();
    }

    /**
     * SAX2: Receive notification of the end of a document.
     */
    public void endDocument() { }


    /**
     * SAX2: Begin the scope of a prefix-URI Namespace mapping.
     *       This has to be passed on to the symbol table!
     */
    public void startPrefixMapping(String prefix, String uri) {
	if (_prefixMapping == null) {
	    _prefixMapping = new Hashtable();
	}
	_prefixMapping.put(prefix, uri);
    }

    /**
     * SAX2: End the scope of a prefix-URI Namespace mapping.
     *       This has to be passed on to the symbol table!
     */
    public void endPrefixMapping(String prefix) { }

    /**
     * SAX2: Receive notification of the beginning of an element.
     *       The parser may re-use the attribute list that we're passed so
     *       we clone the attributes in our own Attributes implementation
     */
    public void startElement(String uri, String localname,
			     String qname, Attributes attributes) 
	throws SAXException {
	final int col = qname.lastIndexOf(':');
	final String prefix = (col == -1) ? null : qname.substring(0, col);

	SyntaxTreeNode element = makeInstance(uri, prefix, 
					localname, attributes);
	if (element == null) {
	    ErrorMsg err = new ErrorMsg(ErrorMsg.ELEMENT_PARSE_ERR,
					prefix+':'+localname);
	    throw new SAXException(err.toString());
	}

	// If this is the root element of the XML document we need to make sure
	// that it contains a definition of the XSL namespace URI
	if (_root == null) {
	    if ((_prefixMapping == null) ||
		(_prefixMapping.containsValue(Constants.XSLT_URI) == false))
		_rootNamespaceDef = false;
	    else
		_rootNamespaceDef = true;
	    _root = element;
	}
	else {
	    SyntaxTreeNode parent = (SyntaxTreeNode)_parentStack.peek();
	    parent.addElement(element);
	    element.setParent(parent);
	}
	element.setAttributes(new AttributeList(attributes));
	element.setPrefixMapping(_prefixMapping);
	
	if (element instanceof Stylesheet) {
	    // Extension elements and excluded elements have to be
	    // handled at this point in order to correctly generate
	    // Fallback elements from <xsl:fallback>s.
	    getSymbolTable().setCurrentNode(element);
	    ((Stylesheet)element).excludeExtensionPrefixes(this);
	}

	_prefixMapping = null;
	_parentStack.push(element);
    }

    /**
     * SAX2: Receive notification of the end of an element.
     */
    public void endElement(String uri, String localname, String qname) {
	_parentStack.pop();
    }

    /**
     * SAX2: Receive notification of character data.
     */
    public void characters(char[] ch, int start, int length) {
	String string = new String(ch, start, length);
	SyntaxTreeNode parent = (SyntaxTreeNode)_parentStack.peek();

	if (string.length() == 0) return;

	// If this text occurs within an <xsl:text> element we append it
	// as-is to the existing text element
	if (parent instanceof Text) {
	    ((Text)parent).setText(string);
	    return;
	}

	// Ignore text nodes that occur directly under <xsl:stylesheet>
	if (parent instanceof Stylesheet) return;

	SyntaxTreeNode bro = parent.lastChild();
	if ((bro != null) && (bro instanceof Text)) {
	    Text text = (Text)bro;
	    if (!text.isTextElement()) {
		if ((length > 1) || ( ((int)ch[0]) < 0x100)) {
		    text.setText(string);
		    return;
		}
	    }
	}

	// Add it as a regular text node otherwise
	parent.addElement(new Text(string));
    }

    private String getTokenValue(String token) {
	final int start = token.indexOf('"');
	final int stop = token.lastIndexOf('"');
	return token.substring(start+1, stop);
    }

    /**
     * SAX2: Receive notification of a processing instruction.
     *       These require special handling for stylesheet PIs.
     */
    public void processingInstruction(String name, String value) {
	// We only handle the <?xml-stylesheet ...?> PI
	if ((_target == null) && (name.equals("xml-stylesheet"))) {

	    String href = null;    // URI of stylesheet found
	    String media = null;   // Media of stylesheet found
	    String title = null;   // Title of stylesheet found
	    String charset = null; // Charset of stylesheet found

	    // Get the attributes from the processing instruction
	    StringTokenizer tokens = new StringTokenizer(value);
	    while (tokens.hasMoreElements()) {
		String token = (String)tokens.nextElement();
		if (token.startsWith("href"))
		    href = getTokenValue(token);
		else if (token.startsWith("media"))
		    media = getTokenValue(token);
		else if (token.startsWith("title"))
		    title = getTokenValue(token);
		else if (token.startsWith("charset"))
		    charset = getTokenValue(token);
	    }

	    // Set the target to this PI's href if the parameters are
	    // null or match the corresponding attributes of this PI.
	    if ( ((_PImedia == null) || (_PImedia.equals(media))) &&
		 ((_PItitle == null) || (_PImedia.equals(title))) &&
		 ((_PIcharset == null) || (_PImedia.equals(charset))) ) {
		_target = href;
	    }
	}
    }

    /**
     * IGNORED - all ignorable whitespace is ignored
     */
    public void ignorableWhitespace(char[] ch, int start, int length) { }

    /**
     * IGNORED - we do not have to do anything with skipped entities
     */
    public void skippedEntity(String name) { }

    /**
     * Store the document locator to later retrieve line numbers of all
     * elements from the stylesheet
     */
    public void setDocumentLocator(Locator locator) {
	_locator = locator;
    }
    
    /**
     * Get the line number, or zero
     * if there is no _locator.
     */
    private int getLineNumber() {
    	int line = 0;
    	if (_locator != null)
    		line = _locator.getLineNumber();
    	return line;
    }

}