static Object find()

in jaxrs-api-2.1/src/main/java/javax/ws/rs/ext/FactoryFinder.java [93:179]
71 lines of code
16 McCabe index (conditional complexity)

    static <T> Object find(final String factoryId, final String fallbackClassName, Class<T> service) throws ClassNotFoundException {
        
        try {
            // If we are deployed into an OSGi environment, leverage it
            Class factoryClass = null;
            try {
                factoryClass = FactoryFinder.class.getClassLoader().loadClass(factoryId);
            } catch (Throwable t) {
                if (service != null) {
                    factoryClass = service;
                } else {
                    throw t;
                }
            }
            Class spiClass = org.apache.servicemix.specs.locator.OsgiLocator.locate(factoryClass, factoryId);
            if (spiClass != null) {
                return spiClass.newInstance();
            }
        } catch (Throwable e) {
        }
        
        ClassLoader classLoader;
        try {
            classLoader = Thread.currentThread().getContextClassLoader();
        } catch (Exception x) {
            throw new ClassNotFoundException(x.toString(), x);
        }

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

            if (is != null) {
                BufferedReader rd =
                        new BufferedReader(new InputStreamReader(is, "UTF-8"));

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

                if (factoryClassName != null &&
                        !"".equals(factoryClassName)) {
                    return newInstance(factoryClassName, classLoader);
                }
            }
        } catch (Exception ex) {
        }


        // try to read from $java.home/lib/jaxrs.properties
        try {
            String javah = System.getProperty("java.home");
            String configFile = javah + File.separator +
                    "lib" + File.separator + "jaxrs.properties";
            File f = new File(configFile);
            if (f.exists()) {
                Properties props = new Properties();
                props.load(new FileInputStream(f));
                String factoryClassName = props.getProperty(factoryId);
                return newInstance(factoryClassName, classLoader);
            }
        } catch (Exception ex) {
        }


        // Use the system property
        try {
            String systemProp =
                    System.getProperty(factoryId);
            if (systemProp != null) {
                return newInstance(systemProp, classLoader);
            }
        } catch (SecurityException se) {
        }

        if (fallbackClassName == null) {
            throw new ClassNotFoundException(
                    "Provider for " + factoryId + " cannot be found", null);
        }

        return newInstance(fallbackClassName, classLoader);
    }