Examples of org.apache.xmlrpc.server.RequestProcessorFactoryFactory

org.apache.xmlrpc.server.RequestProcessorFactoryFactory

The request processor is the object, which is actually performing the request. There is nothing magic about the request processor: It may very well be a POJO. The {@link RequestProcessorFactoryFactory}is passed to the {@link AbstractReflectiveHandlerMapping} at startup.The mapping uses this factory to create instances of {@link RequestProcessorFactory}, which are used to initialize the {@link ReflectiveXmlRpcHandler}. The handler in turn uses its factory to create the actual request processor when a request comes in.

However, the question arises, when and how the request processor is created and whether it needs request specific initialization. The {@link RequestProcessorFactoryFactory} is an object, which makesthat logic pluggable. Unfortunately, we aren't done with a single factory: We even need a factory for factories. The rationale is best explained by looking at the different use cases and how to implement them.

The default {@link RequestProcessorFactoryFactory} is the{@link RequestSpecificProcessorFactoryFactory}. It creates a new processor instance for any request. In other words, it allows to request processor to have some state. This is fine, if the request processor is a lightweight object or needs request specific initialization. In this case, the actual request processor is created and invoked when calling {@link RequestProcessorFactory#getRequestProcessor(XmlRpcRequest)}.

An alternative implementation is the {@link StatelessProcessorFactoryFactory}, which may be used to create stateless request processors. Stateless request processors are typically heavyweight objects, which have an expensive initialization phase. The processor factory, which is created by {@link #getRequestProcessorFactory(Class pClass)} contains aninitialized singleton, which is returned by {@link RequestProcessorFactory#getRequestProcessor(XmlRpcRequest)}.

Other alternatives might be a {@link RequestProcessorFactoryFactory}, which maintains a pool of {@link RequestProcessorFactory} instances. The instances areconfigured by calling {@link RequestProcessorFactory#getRequestProcessor(XmlRpcRequest)}.

     * Adds an instance of this class to the given handler
     * mapping.
   */
  public static void addSystemHandler(final PropertyHandlerMapping pMapping)
            throws XmlRpcException {
      final RequestProcessorFactoryFactory factory = pMapping.getRequestProcessorFactoryFactory();
        final XmlRpcSystemImpl systemHandler = new XmlRpcSystemImpl(pMapping);
        pMapping.setRequestProcessorFactoryFactory(new RequestProcessorFactoryFactory(){
            public RequestProcessorFactory getRequestProcessorFactory(Class pClass)
                    throws XmlRpcException {
                if (XmlRpcSystemImpl.class.equals(pClass)) {
                    return new RequestProcessorFactory(){
                        public Object getRequestProcessor(XmlRpcRequest request)
                                throws XmlRpcException {
                            return systemHandler;
                        }
                    };
                } else {
                    return factory.getRequestProcessorFactory(pClass);
                }
            }
        });
        pMapping.addHandler("system", XmlRpcSystemImpl.class);
    }

     * Adds an instance of this class to the given handler
     * mapping.
   */
  public static void addSystemHandler(final PropertyHandlerMapping pMapping)
            throws XmlRpcException {
      final RequestProcessorFactoryFactory factory = pMapping.getRequestProcessorFactoryFactory();
        final XmlRpcSystemImpl systemHandler = new XmlRpcSystemImpl(pMapping);
        pMapping.setRequestProcessorFactoryFactory(new RequestProcessorFactoryFactory(){
            public RequestProcessorFactory getRequestProcessorFactory(Class pClass)
                    throws XmlRpcException {
                if (XmlRpcSystemImpl.class.equals(pClass)) {
                    return new RequestProcessorFactory(){
                        public Object getRequestProcessor(XmlRpcRequest request)
                                throws XmlRpcException {
                            return systemHandler;
                        }
                    };
                } else {
                    return factory.getRequestProcessorFactory(pClass);
                }
            }
        });
        pMapping.addHandler("system", XmlRpcSystemImpl.class);
    }

Examples of org.apache.xmlrpc.server.RequestProcessorFactoryFactory

Related Classes of org.apache.xmlrpc.server.RequestProcessorFactoryFactory