static Object find()

in jaxp-api-1.3/src/main/java/javax/xml/transform/FactoryFinder.java [145:225]
60 lines of code
19 McCabe index (conditional complexity)

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

        // Figure out which ClassLoader to use for loading the provider
        // class.  If there is a Context ClassLoader then use it.
        
        ClassLoader classLoader = SecuritySupport.getContextClassLoader();
        
        if (classLoader == null) {
            // if we have no Context ClassLoader
            // so use the current ClassLoader
            classLoader = FactoryFinder.class.getClassLoader();
        }

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

        // Use the system property first
        try {
            String systemProp = SecuritySupport.getSystemProperty(factoryId);
            if( systemProp!=null) {                
                if (debug) dPrint("found system property, value=" + systemProp);
                return newInstance(systemProp, classLoader, true );
            }
        } catch (SecurityException se) {
            //if first option fails due to any reason we should try next option in the
            //look up algorithm.
        }

        // try to read from $java.home/lib/jaxp.properties
        try {
            String javah = SecuritySupport.getSystemProperty("java.home");
            String configFile = javah + File.separator +
                "lib" + File.separator + "jaxp.properties";
            String factoryClassName = null;
            if(firstTime){
                synchronized(cacheProps){
                    if(firstTime){
                        File f=new File( configFile );
                        firstTime = false;
                        if(SecuritySupport.doesFileExist(f)){
                            if (debug) dPrint("Read properties file "+f);
                            //cacheProps.load( new FileInputStream(f));
                            cacheProps.load(SecuritySupport.getFileInputStream(f));
                        }
                    }
                }
            }
            factoryClassName = cacheProps.getProperty(factoryId);            

            if(factoryClassName != null){
                if (debug) dPrint("found in $java.home/jaxp.properties, value=" + factoryClassName);
                return newInstance(factoryClassName, classLoader, true);
            }
        } catch(Exception ex ) {
            if( debug ) ex.printStackTrace();
        }

        // Try Jar Service Provider Mechanism
        Object provider = findJarServiceProvider(factoryId);
        if (provider != null) {
            return provider;
        }
        if (fallbackClassName == null) {
            throw new ConfigurationError(
                "Provider for " + factoryId + " cannot be found", null);
        }

        if (debug) dPrint("loaded from fallback value: " + fallbackClassName);
        return newInstance(fallbackClassName, classLoader, true);
    }