private void initializeResourceManager()

in velocity-engine-core/src/main/java/org/apache/velocity/runtime/RuntimeInstance.java [768:847]
61 lines of code
9 McCabe index (conditional complexity)

    private void initializeResourceManager()
    {
        /*
         * Which resource manager?
         */
        Object inst = getProperty(RuntimeConstants.RESOURCE_MANAGER_INSTANCE);
        String rm = getString(RuntimeConstants.RESOURCE_MANAGER_CLASS);

        if (inst != null)
        {
            if (ResourceManager.class.isAssignableFrom(inst.getClass()))
            {
                resourceManager = (ResourceManager)inst;
                resourceManager.initialize(this);
            }
            else
            {
                String msg = inst.getClass().getName() + " object set as resource.manager.instance is not a valid org.apache.velocity.runtime.resource.ResourceManager.";
                log.error(msg);
                throw new VelocityException(msg);
            }
        }
        else if (rm != null && rm.length() > 0)
        {
            /*
             *  if something was specified, then make one.
             *  if that isn't a ResourceManager, consider
             *  this a huge error and throw
             */

            Object o = null;

            try
            {
               o = ClassUtils.getNewInstance( rm );
            }
            catch (ClassNotFoundException cnfe )
            {
                String err = "The specified class for ResourceManager (" + rm
                    + ") does not exist or is not accessible to the current classloader.";
                log.error(err);
                throw new VelocityException(err, cnfe);
            }
            catch (InstantiationException ie)
            {
              throw new VelocityException("Could not instantiate class '" + rm + "'", ie);
            }
            catch (IllegalAccessException ae)
            {
              throw new VelocityException("Cannot access class '" + rm + "'", ae);
            }

            if (!(o instanceof ResourceManager))
            {
                String err = "The specified class for ResourceManager (" + rm
                    + ") does not implement " + ResourceManager.class.getName()
                    + "; Velocity is not initialized correctly.";

                log.error(err);
                throw new VelocityException(err);
            }

            resourceManager = (ResourceManager) o;
            resourceManager.initialize(this);
            setProperty(RESOURCE_MANAGER_INSTANCE, resourceManager);
         }
         else
         {
            /*
             *  someone screwed up.  Lets not fool around...
             */

            String err = "It appears that no class or instance was specified as the"
            + " ResourceManager.  Please ensure that all configuration"
            + " information is correct.";

            log.error(err);
            throw new VelocityException( err );
        }
    }