domconsumer.java

gcc的组建

	 * if ever needed.
	 * Unfortunately the standard DOM factory APIs encourage those costs
	 * to be incurred early.
	 */
	protected Text createText (
	    boolean	isCDATA,
	    char	ch [],
	    int		start,
	    int		length
	) {
	    String	value = new String (ch, start, length);

	    if (isCDATA)
		return document.createCDATASection (value);
	    else
		return document.createTextNode (value);
	}

	// SAX1
	public void characters (char ch [], int start, int length)
	throws SAXException
	{
	    // we can't create populated entity ref nodes using
	    // only public DOM APIs (they've got to be readonly
	    // at creation time)
	    if (currentEntity != null)
		return;

	    Node	lastChild = top.getLastChild ();

	    // merge consecutive text or CDATA nodes if appropriate.
	    if (lastChild instanceof Text) {
		if (consumer.isHidingCDATA ()
			// consecutive Text content ... always merge
			|| (!inCDATA
			    && !(lastChild instanceof CDATASection))
			// consecutive CDATASection content ... don't
			// merge between sections, only within them
			|| (inCDATA && mergeCDATA
			    && lastChild instanceof CDATASection)
			    ) {
		    CharacterData	last = (CharacterData) lastChild;
		    String		value = new String (ch, start, length);
		    
		    last.appendData (value);
		    return;
		}
	    }
	    if (inCDATA && !consumer.isHidingCDATA ()) {
		top.appendChild (createText (true, ch, start, length));
		mergeCDATA = true;
	    } else
		top.appendChild (createText (false, ch, start, length));
	}

	// SAX2
	public void skippedEntity (String name)
	throws SAXException
	{
	    // this callback is useless except to report errors, since
	    // we can't know if the ref was in content, within an
	    // attribute, within a declaration ... only one of those
	    // cases supports more intelligent action than a panic.
	    fatal ("skipped entity: " + name, null);
	}

	// SAX2
	public void startPrefixMapping (String prefix, String uri)
	throws SAXException
	{
	    // reconstruct "xmlns" attributes deleted by all
	    // SAX2 parsers without "namespace-prefixes" = true
	    if ("".equals (prefix))
		attributes.addAttribute ("", "", "xmlns",
			"CDATA", uri);
	    else
		attributes.addAttribute ("", "", "xmlns:" + prefix,
			"CDATA", uri);
	    recreatedAttrs = true;
	}

	// SAX2
	public void endPrefixMapping (String prefix)
	throws SAXException
	    { }

	// SAX2
	public void startElement (
	    String uri,
	    String localName,
	    String qName,
	    Attributes atts
	) throws SAXException
	{
	    // we can't create populated entity ref nodes using
	    // only public DOM APIs (they've got to be readonly)
	    if (currentEntity != null)
		return;

	    // parser discarded basic information; DOM tree isn't writable
	    // without massaging to assign prefixes to all nodes.
	    // the "NSFilter" class does that massaging.
	    if (qName.length () == 0)
		qName = localName;


	    Element	element;
	    int		length = atts.getLength ();

	    if (!isL2) {
		element = document.createElement (qName);

		// first the explicit attributes ...
		length = atts.getLength ();
		for (int i = 0; i < length; i++)
		    element.setAttribute (atts.getQName (i),
					    atts.getValue (i));
		// ... then any recreated ones (DOM deletes duplicates)
		if (recreatedAttrs) {
		    recreatedAttrs = false;
		    length = attributes.getLength ();
		    for (int i = 0; i < length; i++)
			element.setAttribute (attributes.getQName (i),
						attributes.getValue (i));
		    attributes.clear ();
		}

		top.appendChild (element);
		top = element;
		return;
	    }

	    // For an L2 DOM when namespace use is enabled, use
	    // createElementNS/createAttributeNS except when
	    // (a) it's an element in the default namespace, or
	    // (b) it's an attribute with no prefix
	    String	namespace;
	    
	    if (localName.length () != 0)
		namespace = (uri.length () == 0) ? null : uri;
	    else
		namespace = getNamespace (getPrefix (qName), atts);

	    if (namespace == null)
		element = document.createElement (qName);
	    else
		element = document.createElementNS (namespace, qName);

	    populateAttributes (element, atts);
	    if (recreatedAttrs) {
		recreatedAttrs = false;
		// ... DOM deletes any duplicates
		populateAttributes (element, attributes);
		attributes.clear ();
	    }

	    top.appendChild (element);
	    top = element;
	}

	final static String	xmlnsURI = "http://www.w3.org/2000/xmlns/";

	private void populateAttributes (Element element, Attributes attrs)
	throws SAXParseException
	{
	    int		length = attrs.getLength ();

	    for (int i = 0; i < length; i++) {
		String	type = attrs.getType (i);
		String	value = attrs.getValue (i);
		String	name = attrs.getQName (i);
		String	local = attrs.getLocalName (i);
		String	uri = attrs.getURI (i);

		// parser discarded basic information, DOM tree isn't writable
		if (name.length () == 0)
		    name = local;

		// all attribute types other than these three may not
		// contain scoped names... enumerated attributes get
		// reported as NMTOKEN, except for NOTATION values
		if (!("CDATA".equals (type)
			|| "NMTOKEN".equals (type)
			|| "NMTOKENS".equals (type))) {
		    if (value.indexOf (':') != -1) {
			namespaceError (
				"namespace nonconformant attribute value: "
				    + "<" + element.getNodeName ()
				    + " " + name + "='" + value + "' ...>");
		    }
		}

		// xmlns="" is legal (undoes default NS)
		// xmlns:foo="" is illegal
		String prefix = getPrefix (name);
		String namespace;

		if ("xmlns".equals (prefix)) {
		    if ("".equals (value))
			namespaceError ("illegal null namespace decl, " + name);
		    namespace = xmlnsURI;
		} else if ("xmlns".equals (name))
		    namespace = xmlnsURI;

		else if (prefix == null)
		    namespace = null;
		else if (!"".equals(uri) && uri.length () != 0)
		    namespace = uri;
		else
		    namespace = getNamespace (prefix, attrs);

		if (namespace == null)
		    element.setAttribute (name, value);
		else
		    element.setAttributeNS (namespace, name, value);
	    }
	}

	private String getPrefix (String name)
	{
	    int		temp;

	    if ((temp = name.indexOf (':')) > 0)
		return name.substring (0, temp);
	    return null;
	}

	// used with SAX1-level parser output 
	private String getNamespace (String prefix, Attributes attrs)
	throws SAXParseException
	{
	    String namespace;
	    String decl;

	    // defaulting 
	    if (prefix == null) {
		decl = "xmlns";
		namespace = attrs.getValue (decl);
		if ("".equals (namespace))
		    return null;
		else if (namespace != null)
		    return namespace;

	    // "xmlns" is like a keyword
	    // ... according to the Namespace REC, but DOM L2 CR2+
	    // and Infoset violate that by assigning a namespace.
	    // that conflict is resolved elsewhere.
	    } else if ("xmlns".equals (prefix))
		return null;

	    // "xml" prefix is fixed
	    else if ("xml".equals (prefix))
		return "http://www.w3.org/XML/1998/namespace";

	    // otherwise, expect a declaration
	    else {
		decl = "xmlns:" + prefix;
		namespace = attrs.getValue (decl);
	    }
	    
	    // if we found a local declaration, great
	    if (namespace != null)
		return namespace;


	    // ELSE ... search up the tree we've been building
	    for (Node n = top;
		    n != null && n.getNodeType () != Node.DOCUMENT_NODE;
		    n = (Node) n.getParentNode ()) {
		if (n.getNodeType () == Node.ENTITY_REFERENCE_NODE)
		    continue;
		Element e = (Element) n;
		Attr attr = e.getAttributeNode (decl);
		if (attr != null)
		    return attr.getNodeValue ();
	    }
	    // see above re "xmlns" as keyword
	    if ("xmlns".equals (decl))
		return null;

	    namespaceError ("Undeclared namespace prefix: " + prefix);
	    return null;
	}

	// SAX2
	public void endElement (String uri, String localName, String qName)
	throws SAXException
	{
	    // we can't create populated entity ref nodes using
	    // only public DOM APIs (they've got to be readonly)
	    if (currentEntity != null)
		return;

	    top = top.getParentNode ();
	}

	// SAX1 (mandatory reporting if validating)
	public void ignorableWhitespace (char ch [], int start, int length)
	throws SAXException
	{
	    if (consumer.isHidingWhitespace ())
		return;
	    characters (ch, start, length);
	}

	// SAX2 lexical event
	public void startCDATA ()
	throws SAXException
	{
	    inCDATA = true;
	    // true except for the first fragment of a cdata section
	    mergeCDATA = false;
	}
	
	// SAX2 lexical event
	public void endCDATA ()
	throws SAXException
	{
	    inCDATA = false;
	}
	
	// SAX2 lexical event
	//
	// this SAX2 callback merges two unrelated things:
	//	- Declaration of the root element type ... belongs with
	//    the other DTD declaration methods, NOT HERE.
	//	- IDs for the optional external subset ... belongs here
	//    with other lexical information.
	//
	// ...and it doesn't include the internal DTD subset, desired
	// both to support DOM L2 and to enable "pass through" processing
	//
	public void startDTD (String name, String publicId, String SystemId)
	throws SAXException
	{
	    // need to filter out comments and PIs within the DTD
	    inDTD = true;
	}
	
	// SAX2 lexical event
	public void endDTD ()
	throws SAXException
	{
	    inDTD = false;
	}
	
	// SAX2 lexical event
	public void comment (char ch [], int start, int length)
	throws SAXException
	{
	    Node	comment;

	    // we can't create populated entity ref nodes using
	    // only public DOM APIs (they've got to be readonly)
	    if (consumer.isHidingComments ()
		    || inDTD
		    || currentEntity != null)
		return;
	    comment = document.createComment (new String (ch, start, length));
	    top.appendChild (comment);
	}

	/**
	 * May be overridden by subclasses to return true, indicating
	 * that entity reference nodes can be populated and then made
	 * read-only.
	 */
	public boolean canPopulateEntityRefs ()
	    { return false; }

	// SAX2 lexical event
	public void startEntity (String name)
	throws SAXException
	{
	    // are we ignoring what would be contents of an
	    // entity ref, since we can't populate it?
	    if (currentEntity != null)
		return;

	    // Are we hiding all entity boundaries?
	    if (consumer.isHidingReferences ())
		return;

	    // SAX2 shows parameter entities; DOM hides them
	    if (name.charAt (0) == '%' || "[dtd]".equals (name))
		return;

	    // Since we can't create a populated entity ref node in any
	    // standard way, we create an unpopulated one.
	    EntityReference ref = document.createEntityReference (name);
	    top.appendChild (ref);
	    top = ref;

	    // ... allowing subclasses to populate them
	    if (!canPopulateEntityRefs ())
		currentEntity = name;
	}

	// SAX2 lexical event
	public void endEntity (String name)
	throws SAXException
	{
	    if (name.charAt (0) == '%' || "[dtd]".equals (name))
		return;
	    if (name.equals (currentEntity))
		currentEntity = null;
	    if (!consumer.isHidingReferences ())
		top = top.getParentNode ();
	}


	// SAX1 DTD event
	public void notationDecl (
	    String name,
	    String publicId, String SystemId
	) throws SAXException
	{
	    /* IGNORE -- no public DOM API lets us store these
	     * into the doctype node
	     */
	}

	// SAX1 DTD event
	public void unparsedEntityDecl (
	    String name,
	    String publicId, String SystemId,
	    String notationName
	) throws SAXException
	{
	    /* IGNORE -- no public DOM API lets us store these
	     * into the doctype node
	     */
	}

	// SAX2 declaration event
	public void elementDecl (String name, String model)
	throws SAXException
	{
	    /* IGNORE -- no content model support in DOM L2 */
	}

	// SAX2 declaration event
	public void attributeDecl (
	    String eName,
	    String aName,
	    String type,
	    String mode,
	    String value
	) throws SAXException
	{
	    /* IGNORE -- no attribute model support in DOM L2 */
	}

	// SAX2 declaration event
	public void internalEntityDecl (String name, String value)
	throws SAXException
	{
	    /* IGNORE -- no public DOM API lets us store these
	     * into the doctype node
	     */
	}

	// SAX2 declaration event
	public void externalEntityDecl (
	    String name,
	    String publicId,
	    String SystemId
	) throws SAXException
	{
	    /* IGNORE -- no public DOM API lets us store these
	     * into the doctype node
	     */
	}

	//
	// These really should offer the option of nonfatal handling,
	// like other validity errors, though that would cause major
	// chaos in the DOM data structures.  DOM is already spec'd
	// to treat many of these as fatal, so this is consistent.
	//
	private void namespaceError (String description)
	throws SAXParseException
	{
	    SAXParseException err;
	    
	    err = new SAXParseException (description, locator);
	    throw err;
	}
    }
}