static Object find()

in src/main/java/org/apache/servicemix/executors/impl/FactoryFinder.java [155:252]
67 lines of code
14 McCabe index (conditional complexity)

    static Object find(String factoryId, String fallbackClassName)
            throws ConfigurationError {

        final String iFactoryId = factoryId;
        final String iFallbackClassName = fallbackClassName;

        Object obj =
            doPrivileged( new PrivilegedAction() {
                public Object run() {
                    debugPrintln("debug is on");

                    ClassLoader classLoader = findClassLoader();

                    try {
                        // If we are deployed into an OSGi environment, leverage it
                        ClassLoader cl = FactoryFinder.class.getClassLoader();
                        if (cl == null) {
                            cl = ClassLoader.getSystemClassLoader();
                        }
                        Class factoryClass = cl.loadClass(iFactoryId);
                        Class spiClass = org.apache.servicemix.specs.locator.OsgiLocator.locate(factoryClass, iFactoryId);
                        if (spiClass != null) {
                            return spiClass.newInstance();
                        }
                    } catch (Throwable e) {
                    }

                    // Use the system property first
                    try {
                        String systemProp =
                            System.getProperty(iFactoryId);
                        if (systemProp != null) {
                            debugPrintln("found system property " + systemProp);
                            return newInstance(systemProp, classLoader);
                        }
                    } catch (SecurityException se) {
                    }

                    String serviceId = "META-INF/services/" + iFactoryId;
                    // try to find services in CLASSPATH
                    try {
                        InputStream is = null;
                        if (classLoader == null) {
                            is = ClassLoader.getSystemResourceAsStream(serviceId);
                        } else {
                            is = classLoader.getResourceAsStream(serviceId);
                        }

                        if (is != null) {
                            debugPrintln("found " + serviceId);

                            // Read the service provider name in UTF-8 as specified in
                            // the jar spec.  Unfortunately this fails in Microsoft
                            // VJ++, which does not implement the UTF-8
                            // encoding. Theoretically, we should simply let it fail in
                            // that case, since the JVM is obviously broken if it
                            // doesn't support such a basic standard.  But since there
                            // are still some users attempting to use VJ++ for
                            // development, we have dropped in a fallback which makes a
                            // second attempt using the platform's default encoding. In
                            // VJ++ this is apparently ASCII, which is a subset of
                            // UTF-8... and since the strings we'll be reading here are
                            // also primarily limited to the 7-bit ASCII range (at
                            // least, in English versions), this should work well
                            // enough to keep us on the air until we're ready to
                            // officially decommit from VJ++. [Edited comment from
                            // jkesselm]
                            BufferedReader rd;
                            try {
                                rd = new BufferedReader(new InputStreamReader(is, "UTF-8"));
                            } catch (java.io.UnsupportedEncodingException e) {
                                rd = new BufferedReader(new InputStreamReader(is));
                            }

                            String factoryClassName = rd.readLine();
                            rd.close();

                            if (factoryClassName != null &&
                                    ! "".equals(factoryClassName)) {
                                debugPrintln("loaded from services: " + factoryClassName);
                                return newInstance(factoryClassName, classLoader);
                            }
                        }
                    } catch (Exception ex) {
                        if (debug) ex.printStackTrace();
                    }

                    if (iFallbackClassName == null) {
                        throw new ConfigurationError(
                                "Provider for " + iFactoryId + " cannot be found", null);
                    }

                    debugPrintln("loaded from fallback value: " + iFallbackClassName);
                    return newInstance(iFallbackClassName, classLoader);
                }
            });
        return obj;
    }