static List parseDescriptor()

in axiom-api/src/main/java/org/apache/axiom/locator/ImplementationFactory.java [78:129]
48 lines of code
11 McCabe index (conditional complexity)

    static List<Implementation> parseDescriptor(Loader loader, URL url) {
        if (log.isDebugEnabled()) {
            log.debug("Loading " + url);
        }
        List<Implementation> implementations = new ArrayList<Implementation>();
        try {
            // Since this code is used to discover Axiom implementations, we have to use DOM here.
            DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
            dbf.setNamespaceAware(true);
            // Use URL#openStream() (instead of converting the URL to a String and passing it to the
            // parser) to avoid situations where the parser can't reconstruct/interpret the URL.
            InputStream in = url.openStream();
            try {
                Element root = dbf.newDocumentBuilder().parse(in).getDocumentElement();
                QName rootQName = getQName(root);
                if (rootQName.equals(QNAME_IMPLEMENTATIONS)) {
                    Node child = root.getFirstChild();
                    while (child != null) {
                        if (child instanceof Element) {
                            QName childQName = getQName(child);
                            if (childQName.equals(QNAME_IMPLEMENTATION)) {
                                Implementation implementation = parseImplementation(loader, (Element)child);
                                if (implementation != null) {
                                    implementations.add(implementation);
                                }
                            } else {
                                log.warn("Skipping unexpected element " + childQName + "; only "
                                        + QNAME_IMPLEMENTATION + " is expected");
                            }
                        }
                        child = child.getNextSibling();
                    }
                } else {
                    log.error(url + " is not a valid implementation descriptor: unexpected root element "
                            + rootQName + "; expected " + QNAME_IMPLEMENTATIONS);
                }
            } finally {
                in.close();
            }
        } catch (ParserConfigurationException ex) {
            // If we get here, something went badly wrong
            throw new Error(ex);
        } catch (IOException ex) {
            log.error("Unable to read " + url, ex);
        } catch (SAXException ex) {
            log.error("Parser error while reading " + url, ex);
        }
        if (log.isDebugEnabled()) {
            log.debug("Discovered implementations: " + implementations);
        }
        return implementations;
    }