private static StAXDialect detectDialectFromJarManifest()

in axiom-api/src/main/java/org/apache/axiom/util/stax/dialect/StAXDialectDetector.java [225:289]
58 lines of code
16 McCabe index (conditional complexity)

    private static StAXDialect detectDialectFromJarManifest(URL rootUrl) {
        if (rootUrl.getProtocol().equals("jrt")) {
            // We get here for the StAX implementation in the JRE for Java 9 and above. There is no
            // manifest for the runtime classes, so stop here.
            return null;
        }
        Manifest manifest;
        try {
            URL metaInfUrl = new URL(rootUrl, "META-INF/MANIFEST.MF");
            InputStream is = metaInfUrl.openStream();
            try {
                manifest = new Manifest(is);
            } finally {
                is.close();
            }
        } catch (IOException ex) {
            log.warn("Unable to load manifest for StAX implementation at " + rootUrl);
            return UnknownStAXDialect.INSTANCE;
        }
        Attributes attrs = manifest.getMainAttributes();
        String title = attrs.getValue(IMPLEMENTATION_TITLE);
        String symbolicName = attrs.getValue(BUNDLE_SYMBOLIC_NAME);
        if (symbolicName != null) {
            int i = symbolicName.indexOf(';');
            if (i != -1) {
                symbolicName = symbolicName.substring(0, i);
            }
        }
        String vendor = attrs.getValue(IMPLEMENTATION_VENDOR);
        if (vendor == null) {
            vendor = attrs.getValue(BUNDLE_VENDOR);
        }
        String versionString = attrs.getValue(IMPLEMENTATION_VERSION);
        if (versionString == null) {
            versionString = attrs.getValue(BUNDLE_VERSION);
        }
        if (log.isDebugEnabled()) {
            log.debug("StAX implementation at " + rootUrl + " is:\n" +
                    "  Title:         " + title + "\n" +
                    "  Symbolic name: " + symbolicName + "\n" +
                    "  Vendor:        " + vendor + "\n" +
                    "  Version:       " + versionString);
        }
        
        if (title != null && title.toLowerCase(Locale.ENGLISH).contains("woodstox")) {
            Version version = new Version(versionString);
            return version.getComponent(0) >= 4 ? Woodstox4Dialect.INSTANCE : null;
        } else if (title != null && title.indexOf("SJSXP") != -1) {
            return new SJSXPDialect(false);
        } else if ("com.bea.core.weblogic.stax".equals(symbolicName)) {
            // Weblogic's StAX implementation doesn't support CDATA section reporting and there are
            // a couple of additional test cases (with respect to BEA's reference implementation)
            // that fail.
            log.warn("Weblogic's StAX implementation is unsupported and some Axiom features will not work " +
            		"as expected! Please use Woodstox instead.");
            // This is the best match we can return in this case.
            return BEADialect.INSTANCE;
        } else if ("BEA".equals(vendor)) {
            return BEADialect.INSTANCE;
        } else if ("com.ibm.ws.prereq.banshee".equals(symbolicName)) {
            return XLXP2Dialect.INSTANCE;
        } else {
            return null;
        }
    }