saxoutputter.java

JAVA的Jdom包

        // Output node list as a document fragment.
        elementContent(nodes, new NamespaceStack());
    }

    /**
     * This will output a single JDOM nodes as a fragment of an XML
     * document, firing off the SAX events that have been registered.
     * <p>
     * <strong>Warning</strong>: This method does not call the
     * {@link ContentHandler#setDocumentLocator},
     * {@link ContentHandler#startDocument} and
     * {@link ContentHandler#endDocument} callbacks on the
     * {@link #setContentHandler ContentHandler}.  The user shall
     * invoke these methods directly prior/after outputting the
     * document fragments.</p>
     *
     * @param node the <code>Content</code> node to output.
     *
     * @throws JDOMException if any error occurred.
     *
     * @see #outputFragment(java.util.List)
     */
    public void outputFragment(Content node) throws JDOMException {
        if (node == null) {
            return;
        }

        // Output single node as a document fragment.
        elementContent(node, new NamespaceStack());
    }

    /**
     * This parses a DTD declaration to fire the related events towards
     * the registered handlers.
     *
     * @param document <code>JDOM Document</code> the DocType is to
     *                 process.
     */
    private void dtdEvents(Document document) throws JDOMException {
        DocType docType = document.getDocType();

        // Fire DTD-related events only if handlers have been registered.
        if ((docType != null) &&
            ((dtdHandler != null) || (declHandler != null))) {

            // Build a dummy XML document that only references the DTD...
            String dtdDoc = new XMLOutputter().outputString(docType);

            try {
                // And parse it to fire DTD events.
                createDTDParser().parse(new InputSource(
                                                new StringReader(dtdDoc)));

                // We should never reach this point as the document is
                // ill-formed; it does not have any root element.
            }
            catch (SAXParseException e) {
                // Expected exception: There's no root element in document.
            }
            catch (SAXException e) {
                throw new JDOMException("DTD parsing error", e);
            }
            catch (IOException e) {
                throw new JDOMException("DTD parsing error", e);
            }
        }
    }

    /**
     * <p>
     * This method tells you the line of the XML file being parsed.
     * For an in-memory document, it's meaningless. The location
     * is only valid for the current parsing lifecycle, but
     * the document has already been parsed. Therefore, it returns
     * -1 for both line and column numbers.
     * </p>
     *
     * @param document JDOM <code>Document</code>.
     */
    private void documentLocator(Document document) {
        locator = new JDOMLocator();
        String publicID = null;
        String systemID = null;

        if (document != null) {
            DocType docType = document.getDocType();
            if (docType != null) {
                publicID = docType.getPublicID();
                systemID = docType.getSystemID();
            }
        }
        locator.setPublicId(publicID);
        locator.setSystemId(systemID);
        locator.setLineNumber(-1);
        locator.setColumnNumber(-1);

        contentHandler.setDocumentLocator(locator);
    }

    /**
     * <p>
     * This method is always the second method of all callbacks in
     * all handlers to be invoked (setDocumentLocator is always first).
     * </p>
     */
    private void startDocument() throws JDOMException {
        try {
            contentHandler.startDocument();
        }
        catch (SAXException se) {
            throw new JDOMException("Exception in startDocument", se);
        }
    }

    /**
     * <p>
     * Always the last method of all callbacks in all handlers
     * to be invoked.
     * </p>
     */
    private void endDocument() throws JDOMException {
        try {
            contentHandler.endDocument();

            // reset locator
            locator = null;
        }
        catch (SAXException se) {
            throw new JDOMException("Exception in endDocument", se);
        }
    }

    /**
     * <p>
     * This will invoke the <code>ContentHandler.processingInstruction</code>
     * callback when a processing instruction is encountered.
     * </p>
     *
     * @param pi <code>ProcessingInstruction</code> containing target and data.
     */
    private void processingInstruction(ProcessingInstruction pi)
                           throws JDOMException {
        if (pi != null) {
            String target = pi.getTarget();
            String data = pi.getData();
            try {
                contentHandler.processingInstruction(target, data);
            }
            catch (SAXException se) {
                throw new JDOMException(
                    "Exception in processingInstruction", se);
            }
        }
    }

    /**
     * <p>
     * This will recursively invoke all of the callbacks for a particular
     * element.
     * </p>
     *
     * @param element <code>Element</code> used in callbacks.
     * @param namespaces <code>List</code> stack of Namespaces in scope.
     */
    private void element(Element element, NamespaceStack namespaces)
                           throws JDOMException {
        // used to check endPrefixMapping
        int previouslyDeclaredNamespaces = namespaces.size();

        // contentHandler.startPrefixMapping()
        Attributes nsAtts = startPrefixMapping(element, namespaces);

        // contentHandler.startElement()
        startElement(element, nsAtts);

        // handle content in the element
        elementContent(element.getContent(), namespaces);

        // update locator
        if (locator != null) {
          locator.setNode(element);
        }

        // contentHandler.endElement()
        endElement(element);

        // contentHandler.endPrefixMapping()
        endPrefixMapping(namespaces, previouslyDeclaredNamespaces);
    }

    /**
     * <p>
     * This will invoke the <code>ContentHandler.startPrefixMapping</code>
     * callback
     * when a new namespace is encountered in the <code>Document</code>.
     * </p>
     *
     * @param element <code>Element</code> used in callbacks.
     * @param namespaces <code>List</code> stack of Namespaces in scope.
     *
     * @return <code>Attributes</code> declaring the namespaces local to
     * <code>element</code> or <code>null</code>.
     */
    private Attributes startPrefixMapping(Element element,
                                          NamespaceStack namespaces)
                                                   throws JDOMException {
        AttributesImpl nsAtts = null;   // The namespaces as xmlns attributes

        Namespace ns = element.getNamespace();
        if (ns != Namespace.XML_NAMESPACE) {
            String prefix = ns.getPrefix();
            String uri = namespaces.getURI(prefix);
            if (!ns.getURI().equals(uri)) {
                namespaces.push(ns);
                nsAtts = this.addNsAttribute(nsAtts, ns);
                try {
                    contentHandler.startPrefixMapping(prefix, ns.getURI());
                }
                catch (SAXException se) {
                   throw new JDOMException(
                       "Exception in startPrefixMapping", se);
                }
            }
        }

        // Fire additional namespace declarations
        List additionalNamespaces = element.getAdditionalNamespaces();
        if (additionalNamespaces != null) {
            Iterator itr = additionalNamespaces.iterator();
            while (itr.hasNext()) {
                ns = (Namespace)itr.next();
                String prefix = ns.getPrefix();
                String uri = namespaces.getURI(prefix);
                if (!ns.getURI().equals(uri)) {
                    namespaces.push(ns);
                    nsAtts = this.addNsAttribute(nsAtts, ns);
                    try {
                        contentHandler.startPrefixMapping(prefix, ns.getURI());
                    }
                    catch (SAXException se) {
                        throw new JDOMException(
                            "Exception in startPrefixMapping", se);
                    }
                }
            }
        }
        return nsAtts;
    }

    /**
     * <p>
     * This will invoke the <code>endPrefixMapping</code> callback in the
     * <code>ContentHandler</code> when a namespace is goes out of scope
     * in the <code>Document</code>.
     * </p>
     *
     * @param namespaces <code>List</code> stack of Namespaces in scope.
     * @param previouslyDeclaredNamespaces number of previously declared
     * namespaces
     */
    private void endPrefixMapping(NamespaceStack namespaces,
                                  int previouslyDeclaredNamespaces)
                                                throws JDOMException {
        while (namespaces.size() > previouslyDeclaredNamespaces) {
            String prefix = namespaces.pop();
            try {
                contentHandler.endPrefixMapping(prefix);
            }
            catch (SAXException se) {
                throw new JDOMException("Exception in endPrefixMapping", se);
            }
        }
    }

    /**
     * <p>
     * This will invoke the <code>startElement</code> callback
     * in the <code>ContentHandler</code>.
     * </p>
     *
     * @param element <code>Element</code> used in callbacks.
     * @param nsAtts <code>List</code> of namespaces to declare with
     * the element or <code>null</code>.
     */
    private void startElement(Element element, Attributes nsAtts)
                      throws JDOMException {
        String namespaceURI = element.getNamespaceURI();
        String localName = element.getName();
        String rawName = element.getQualifiedName();

        // Allocate attribute list.
        AttributesImpl atts = (nsAtts != null)?
                              new AttributesImpl(nsAtts): new AttributesImpl();

        List attributes = element.getAttributes();
        Iterator i = attributes.iterator();
        while (i.hasNext()) {
            Attribute a = (Attribute) i.next();
            atts.addAttribute(a.getNamespaceURI(),
                              a.getName(),
                              a.getQualifiedName(),
                              getAttributeTypeName(a.getAttributeType()),
                              a.getValue());
        }

        try {
            contentHandler.startElement(namespaceURI, localName, rawName, atts);
        }
        catch (SAXException se) {
            throw new JDOMException("Exception in startElement", se);
        }
    }

    /**
     * <p>
     * This will invoke the <code>endElement</code> callback
     * in the <code>ContentHandler</code>.
     * </p>
     *
     * @param element <code>Element</code> used in callbacks.
     */
    private void endElement(Element element) throws JDOMException {
        String namespaceURI = element.getNamespaceURI();
        String localName = element.getName();
        String rawName = element.getQualifiedName();

        try {
            contentHandler.endElement(namespaceURI, localName, rawName);
        }
        catch (SAXException se) {
            throw new JDOMException("Exception in endElement", se);
        }
    }

    /**
     * <p>
     * This will invoke the callbacks for the content of an element.
     * </p>
     *
     * @param content element content as a <code>List</code> of nodes.
     * @param namespaces <code>List</code> stack of Namespaces in scope.
     */
    private void elementContent(List content, NamespaceStack namespaces)
                      throws JDOMException {
        for (Iterator i=content.iterator(); i.hasNext(); ) {
            Object obj = i.next();

            if (obj instanceof Content) {
                this.elementContent((Content)obj, namespaces);
            }
            else {
                // Not a valid element child. This could happen with
                // application-provided lists which may contain non
                // JDOM objects.
                handleError(new JDOMException(
                                        "Invalid element content: " + obj));
            }
        }
    }