feedreader1.java

Read web RSS Feeds to break it into simple tags elements

        }
    }

    /**
     * Recursive routine to print out DOM tree nodes
     */
    private void echo(Node n) {
        // Indent to the current level before printing anything
       // outputIndentation();

        int type = n.getNodeType();
        switch (type) {
        case Node.ATTRIBUTE_NODE:
//            out.print("ATTR:");
            printlnCommon(n);
            break;
        case Node.CDATA_SECTION_NODE:
//            out.print("CDATA:");
            printlnCommon(n);
            break;
        case Node.COMMENT_NODE:
//            out.print("COMM:");
            printlnCommon(n);
            break;
        case Node.DOCUMENT_FRAGMENT_NODE:
//            out.print("DOC_FRAG:");
            printlnCommon(n);
            break;
        case Node.DOCUMENT_NODE:
//            out.print("DOC:");
            printlnCommon(n);
            break;
        case Node.DOCUMENT_TYPE_NODE:
//            out.print("DOC_TYPE:");
            printlnCommon(n);

            // Print entities if any
            NamedNodeMap nodeMap = ((DocumentType)n).getEntities();
            indent += 2;
            for (int i = 0; i < nodeMap.getLength(); i++) {
                Entity entity = (Entity)nodeMap.item(i);
                echo(entity);
            }
            indent -= 2;
            break;
        case Node.ELEMENT_NODE:
//            out.print("ELEM:");
            printlnCommon(n);

            // Print attributes if any.  Note: element attributes are not
            // children of ELEMENT_NODEs but are properties of their
            // associated ELEMENT_NODE.  For this reason, they are printed
            // with 2x the indent level to indicate this.
            NamedNodeMap atts = n.getAttributes();
            indent += 2;
            for (int i = 0; i < atts.getLength(); i++) {
                Node att = atts.item(i);
                echo(att);
            }
            indent -= 2;
            break;
        case Node.ENTITY_NODE:
//            out.print("ENT:");
            printlnCommon(n);
            break;
        case Node.ENTITY_REFERENCE_NODE:
//            out.print("ENT_REF:");
            printlnCommon(n);
            break;
        case Node.NOTATION_NODE:
//            out.print("NOTATION:");
            printlnCommon(n);
            break;
        case Node.PROCESSING_INSTRUCTION_NODE:
//            out.print("PROC_INST:");
            printlnCommon(n);
            break;
        case Node.TEXT_NODE:
//            out.print("TEXT:");
            printlnCommon(n);
            break;
        default:
            out.print("UNSUPPORTED NODE: " + type);
            printlnCommon(n);
            break;
        }

        // Print children if any
        indent++;
        for (Node child = n.getFirstChild(); child != null;
             child = child.getNextSibling()) {
            echo(child);
        }
        indent--;
    }

    private static void usage() {
        System.err.println("Usage: DOMEcho [-options] <file.xml>");
        System.err.println("       -dtd = DTD validation");
        System.err.println("       -ws = do not create element content whitespace nodes");
        System.err.println("       -co[mments] = do not create comment nodes");
        System.err.println("       -cd[ata] = put CDATA into Text nodes");
        System.err.println("       -e[ntity-ref] = create EntityReference nodes");
        System.err.println("       -usage or -help = this message");
        System.exit(1);
    }

    public static void main(String[] args) throws Exception {
        String filename = null;
        boolean dtdValidate = false;

        boolean ignoreWhitespace = false;
        boolean ignoreComments = false;
        boolean putCDATAIntoText = false;
        boolean createEntityRefs = false;

        for (int i = 0; i < args.length; i++) {
            if (args[i].equals("-dtd")) {
                dtdValidate = true;
            } else if (args[i].equals("-ws")) {
                ignoreWhitespace = true;
            } else if (args[i].startsWith("-co")) {
                ignoreComments = true;
            } else if (args[i].startsWith("-cd")) {
                putCDATAIntoText = true;
            } else if (args[i].startsWith("-e")) {
                createEntityRefs = true;
            } else if (args[i].equals("-usage")) {
                usage();
            } else if (args[i].equals("-help")) {
                usage();
            } else {
                filename = args[i];

                // Must be last arg
                if (i != args.length - 1) {
                    usage();
                }
            }
        }
        if (filename == null) {
            usage();
        }

        // Step 1: create a DocumentBuilderFactory and configure it
        DocumentBuilderFactory dbf =
            DocumentBuilderFactory.newInstance();

        // Set namespaceAware to true to get a DOM Level 2 tree with nodes
        // containing namesapce information.  This is necessary because the
        // default value from JAXP 1.0 was defined to be false.
        dbf.setNamespaceAware(true);

        // Set the validation mode to either: no validation, DTD
        // validation 
        dbf.setValidating(dtdValidate);


        // Optional: set various configuration options
        dbf.setIgnoringComments(ignoreComments);
        dbf.setIgnoringElementContentWhitespace(ignoreWhitespace);
        dbf.setCoalescing(putCDATAIntoText);
        // The opposite of creating entity ref nodes is expanding them inline
        dbf.setExpandEntityReferences(!createEntityRefs);

        // Step 2: create a DocumentBuilder that satisfies the constraints
        // specified by the DocumentBuilderFactory
        DocumentBuilder db = dbf.newDocumentBuilder();

        // Set an ErrorHandler before parsing
        OutputStreamWriter errorWriter =
            new OutputStreamWriter(System.err, outputEncoding);
        db.setErrorHandler(
            new MyErrorHandler(new PrintWriter(errorWriter, true)));

        // Step 3: parse the input file
        Document doc = db.parse(new File(filename));

        // Print out the DOM tree
        OutputStreamWriter outWriter =
            new OutputStreamWriter(System.out, outputEncoding);
        FeedReader1 FR1= new FeedReader1(new PrintWriter(outWriter, true));
	FR1.echo(doc);
	FR1.FD.showFeeds();
    }

    // Error handler to report errors and warnings
    private static class MyErrorHandler implements ErrorHandler {
        /** Error handler output goes here */
        private PrintWriter out;

        MyErrorHandler(PrintWriter out) {
            this.out = out;
        }

        /**
         * Returns a string describing parse exception details
         */
        private String getParseExceptionInfo(SAXParseException spe) {
            String systemId = spe.getSystemId();
            if (systemId == null) {
                systemId = "null";
            }
            String info = "URI=" + systemId +
                " Line=" + spe.getLineNumber() +
                ": " + spe.getMessage();
            return info;
        }

        // The following methods are standard SAX ErrorHandler methods.
        // See SAX documentation for more info.

        public void warning(SAXParseException spe) throws SAXException {
            out.println("Warning: " + getParseExceptionInfo(spe));
        }
        
        public void error(SAXParseException spe) throws SAXException {
            String message = "Error: " + getParseExceptionInfo(spe);
            throw new SAXException(message);
        }

        public void fatalError(SAXParseException spe) throws SAXException {
            String message = "Fatal Error: " + getParseExceptionInfo(spe);
            throw new SAXException(message);
        }
    }
}