public static synchronized List providers()

in src/main/java/org/apache/neethi/util/Service.java [70:147]
56 lines of code
14 McCabe index (conditional complexity)

    public static synchronized <T> List<? extends T> providers(Class<T> cls) {

        String serviceFile = "META-INF/services/" + cls.getName();

        List<T> l = cast(instanceMap.get(serviceFile));
        if (l != null) {
            return l;
        }

        l = new ArrayList<T>();
        instanceMap.put(serviceFile, l);

        ClassLoader cl = null;
        try {
            cl = cls.getClassLoader();
        } catch (SecurityException se) {
            // Ooops! can't get his class loader.
        }
        // Can always request your own class loader. But it might be 'null'.
        if (cl == null) {
            cl = Service.class.getClassLoader();
        }
        if (cl == null) {
            cl = ClassLoader.getSystemClassLoader();
        }

        // No class loader so we can't find 'serviceFile'.
        if (cl == null) {
            return l;
        }

        Enumeration<URL> e;
        try {
            e = cl.getResources(serviceFile);
        } catch (IOException ioe) {
            return l;
        }

        while (e.hasMoreElements()) {
            URL u = e.nextElement();
            try (Reader r  = new InputStreamReader(u.openStream(), StandardCharsets.UTF_8);
                BufferedReader br = new BufferedReader(r)) {

                String line = br.readLine();
                while (line != null) {
                    try {
                        // First strip any comment...
                        int idx = line.indexOf('#');
                        if (idx != -1) {
                            line = line.substring(0, idx);
                        }

                        // Trim whitespace.
                        line = line.trim();

                        // If nothing left then loop around...
                        if (line.length() == 0) {
                            line = br.readLine();
                            continue;
                        }

                        // Try and load the class
                        Object obj = cl.loadClass(line).newInstance();
                        // stick it into our vector...
                        l.add(cls.cast(obj));
                    } catch (Exception ex) {
                        // Just try the next line
                    }
                    line = br.readLine();
                }
            } catch (Exception ex) {
                // Just try the next file...
            } catch (LinkageError le) {
                // Just try the next file...
            }
        }
        return l;
    }