org.springframework.web.portlet
Class DispatcherPortlet

java.lang.Object
  javax.portlet.GenericPortlet
      org.springframework.web.portlet.GenericPortletBean
          org.springframework.web.portlet.FrameworkPortlet
              org.springframework.web.portlet.DispatcherPortlet

All Implemented Interfaces:

EventListener, Portlet, PortletConfig, ApplicationListener

public class DispatcherPortlet
extends FrameworkPortlet

Central dispatcher for use within the Portlet MVC framework, e.g. for web UI controllers. Dispatches to registered handlers for processing a portlet request.

This portlet is very flexible: It can be used with just about any workflow, with the installation of the appropriate adapter classes. It offers the following functionality that distinguishes it from other request-driven portlet MVC frameworks:

• It is based around a JavaBeans configuration mechanism.
• It can use any HandlerMapping implementation - pre-built or provided as part of an application - to control the routing of requests to handler objects. Default is PortletModeHandlerMapping. HandlerMapping objects can be defined as beans in the portlet's application context, implementing the HandlerMapping interface, overriding the default HandlerMapping if present. HandlerMappings can be given any bean name (they are tested by type).
• It can use any HandlerAdapter; this allows to use any handler interface. The default adapter is SimpleControllerHandlerAdapter for Spring's Controller interface. HandlerAdapter objects can be added as beans in the application context, overriding the default HandlerAdapter. Like HandlerMappings, HandlerAdapters can be given any bean name (they are tested by type).
• The dispatcher's exception resolution strategy can be specified via a HandlerExceptionResolver, for example mapping certain exceptions to error pages. Default is none. Additional HandlerExceptionResolvers can be added through the application context. HandlerExceptionResolver can be given any bean name (they are tested by type).
• Its view resolution strategy can be specified via a ViewResolver implementation, resolving symbolic view names into View objects. Default is InternalResourceViewResolver. ViewResolver objects can be added as beans in the application context, overriding the default ViewResolver. ViewResolvers can be given any bean name (they are tested by type).
• The dispatcher's strategy for resolving multipart requests is determined by a PortletMultipartResolver implementation. An implementations for Jakarta Commons FileUpload is included: CommonsPortletMultipartResolver. The MultipartResolver bean name is "portletMultipartResolver"; default is none.

A web application can define any number of DispatcherPortlets. Each portlet will operate in its own namespace, loading its own application context with mappings, handlers, etc. Only the root application context as loaded by ContextLoaderListener, if any, will be shared.

Thanks to Rainer Schmitz and Nick Lothian for their suggestions!

Since:

2.0

Author:

William G. Thompson, Jr., John A. Lewis, Juergen Hoeller

See Also:

Controller, ViewRendererServlet, ContextLoaderListener

Field Summary

static String	ACTION_EXCEPTION_RENDER_PARAMETER This render parameter is used to indicate forward to the render phase that an exception occurred during the action phase.
static String	ACTION_EXCEPTION_SESSION_ATTRIBUTE Unlike the Servlet version of this class, we have to deal with the two-phase nature of the portlet request.
static String	DEFAULT_VIEW_RENDERER_URL Default URL to ViewRendererServlet.
static String	HANDLER_ADAPTER_BEAN_NAME Well-known name for the HandlerAdapter object in the bean factory for this namespace.
static String	HANDLER_EXCEPTION_RESOLVER_BEAN_NAME Well-known name for the HandlerExceptionResolver object in the bean factory for this namespace.
static String	HANDLER_EXECUTION_CHAIN_ATTRIBUTE Request attribute to hold the currently chosen HandlerExecutionChain.
static String	HANDLER_MAPPING_BEAN_NAME Well-known name for the HandlerMapping object in the bean factory for this namespace.
static String	MULTIPART_RESOLVER_BEAN_NAME Well-known name for the PortletMultipartResolver object in the bean factory for this namespace.
static String	PAGE_NOT_FOUND_LOG_CATEGORY Log category to use when no mapped handler is found for a request.
protected static Log	pageNotFoundLogger Additional logger to use when no mapped handler is found for a request.
static String	VIEW_RESOLVER_BEAN_NAME Well-known name for the ViewResolver object in the bean factory for this namespace.

Fields inherited from class org.springframework.web.portlet.FrameworkPortlet

DEFAULT_CONTEXT_CLASS, DEFAULT_NAMESPACE_SUFFIX, DEFAULT_USERINFO_ATTRIBUTE_NAMES, PORTLET_CONTEXT_PREFIX

Fields inherited from class org.springframework.web.portlet.GenericPortletBean

logger

Constructor Summary

DispatcherPortlet()

Method Summary

protected LocaleContext	buildLocaleContext(PortletRequest request) Build a LocaleContext for the given request, exposing the request's primary locale as current locale.
protected ActionRequest	checkMultipart(ActionRequest request) Convert the request into a multipart request, and make multipart resolver available.
protected Object	createDefaultStrategy(ApplicationContext context, Class clazz) Create a default strategy.
protected void	doActionService(ActionRequest request, ActionResponse response) Processes the actual dispatching to the handler for action requests.
protected void	doRenderService(RenderRequest request, RenderResponse response) Processes the actual dispatching to the handler for render requests.
protected List	getDefaultStrategies(ApplicationContext context, Class strategyInterface) Create a List of default strategy objects for the given strategy interface.
protected Object	getDefaultStrategy(ApplicationContext context, Class strategyInterface) Return the default strategy object for the given strategy interface.
protected HandlerExecutionChain	getHandler(PortletRequest request, boolean cache) Return the HandlerExecutionChain for this request.
protected HandlerAdapter	getHandlerAdapter(Object handler) Return the HandlerAdapter for this handler object.
PortletMultipartResolver	getMultipartResolver() Obtain this portlet's PortletMultipartResolver, if any.
protected void	initStrategies(ApplicationContext context) Refresh the strategy objects that this portlet uses.
protected void	noHandlerFound(PortletRequest request, PortletResponse response) No handler found -> throw appropriate exception.
void	onRefresh(ApplicationContext context) This implementation calls initStrategies(org.springframework.context.ApplicationContext).
protected ModelAndView	processHandlerException(RenderRequest request, RenderResponse response, Object handler, Exception ex) Determine an error ModelAndView via the registered HandlerExceptionResolvers.
protected void	render(ModelAndView mv, RenderRequest request, RenderResponse response) Render the given ModelAndView.
protected View	resolveViewName(String viewName, Map model, RenderRequest request) Resolve the given view name into a View object (to be rendered).
void	setDetectAllHandlerAdapters(boolean detectAllHandlerAdapters) Set whether to detect all HandlerAdapter beans in this portlet's context.
void	setDetectAllHandlerExceptionResolvers(boolean detectAllHandlerExceptionResolvers) Set whether to detect all HandlerExceptionResolver beans in this portlet's context.
void	setDetectAllHandlerMappings(boolean detectAllHandlerMappings) Set whether to detect all HandlerMapping beans in this portlet's context.
void	setDetectAllViewResolvers(boolean detectAllViewResolvers) Set whether to detect all ViewResolver beans in this portlet's context.
void	setThreadContextInheritable(boolean threadContextInheritable) Set whether to expose the LocaleContext and RequestAttributes as inheritable for child threads (using an InheritableThreadLocal).
void	setViewRendererUrl(String viewRendererUrl) Set the URL to the ViewRendererServlet.

Methods inherited from class org.springframework.web.portlet.FrameworkPortlet

createPortletApplicationContext, destroy, doDispatch, getContextClass, getContextConfigLocation, getNamespace, getPortletApplicationContext, getPortletContextAttributeName, getUserinfoUsernameAttributes, getUsernameForRequest, initFrameworkPortlet, initPortletApplicationContext, initPortletBean, isPublishContext, isPublishEvents, onApplicationEvent, postProcessPortletApplicationContext, processAction, processRequest, refresh, setContextClass, setContextConfigLocation, setNamespace, setPublishContext, setPublishEvents, setUserinfoUsernameAttributes

Methods inherited from class org.springframework.web.portlet.GenericPortletBean

addRequiredProperty, getPortletContext, getPortletName, init, initBeanWrapper

Methods inherited from class javax.portlet.GenericPortlet

doEdit, doHelp, doView, getInitParameter, getInitParameterNames, getPortletConfig, getResourceBundle, getTitle, init, render

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

MULTIPART_RESOLVER_BEAN_NAME

public static final String MULTIPART_RESOLVER_BEAN_NAME

Well-known name for the PortletMultipartResolver object in the bean factory for this namespace.

See Also:

Constant Field Values

HANDLER_MAPPING_BEAN_NAME

public static final String HANDLER_MAPPING_BEAN_NAME

Well-known name for the HandlerMapping object in the bean factory for this namespace. Only used when "detectAllHandlerMappings" is turned off.

See Also:

setDetectAllViewResolvers(boolean), Constant Field Values

HANDLER_ADAPTER_BEAN_NAME

public static final String HANDLER_ADAPTER_BEAN_NAME

Well-known name for the HandlerAdapter object in the bean factory for this namespace. Only used when "detectAllHandlerAdapters" is turned off.

See Also:

setDetectAllHandlerAdapters(boolean), Constant Field Values

HANDLER_EXCEPTION_RESOLVER_BEAN_NAME

public static final String HANDLER_EXCEPTION_RESOLVER_BEAN_NAME

Well-known name for the HandlerExceptionResolver object in the bean factory for this namespace. Only used when "detectAllHandlerExceptionResolvers" is turned off.

See Also:

setDetectAllViewResolvers(boolean), Constant Field Values

VIEW_RESOLVER_BEAN_NAME

public static final String VIEW_RESOLVER_BEAN_NAME

Well-known name for the ViewResolver object in the bean factory for this namespace.

See Also:

Constant Field Values

DEFAULT_VIEW_RENDERER_URL

public static final String DEFAULT_VIEW_RENDERER_URL

Default URL to ViewRendererServlet. This bridge servlet is used to convert portlet render requests to servlet requests in order to leverage the view support in the org.springframework.web.view package.

See Also:

Constant Field Values

HANDLER_EXECUTION_CHAIN_ATTRIBUTE

public static final String HANDLER_EXECUTION_CHAIN_ATTRIBUTE

Request attribute to hold the currently chosen HandlerExecutionChain. Only used for internal optimizations.

ACTION_EXCEPTION_SESSION_ATTRIBUTE

public static final String ACTION_EXCEPTION_SESSION_ATTRIBUTE

Unlike the Servlet version of this class, we have to deal with the two-phase nature of the portlet request. To do this, we need to pass forward any exception that occurs during the action phase, so that it can be displayed in the render phase. The only direct way to pass things forward and preserve them for each render request is through render parameters, but these are limited to String objects and we need to pass the Exception itself. The only other way to do this is in the session. The bad thing about using the session is that we have no way of knowing when we are done re-rendering the request and so we don't know when we can remove the objects from the session. So we will end up polluting the session with an old exception when we finally leave the render phase of one request and move on to something else.

ACTION_EXCEPTION_RENDER_PARAMETER

public static final String ACTION_EXCEPTION_RENDER_PARAMETER

This render parameter is used to indicate forward to the render phase that an exception occurred during the action phase.

See Also:

Constant Field Values

PAGE_NOT_FOUND_LOG_CATEGORY

public static final String PAGE_NOT_FOUND_LOG_CATEGORY

Log category to use when no mapped handler is found for a request.

See Also:

Constant Field Values

pageNotFoundLogger

protected static final Log pageNotFoundLogger

Additional logger to use when no mapped handler is found for a request.

Constructor Detail

DispatcherPortlet

public DispatcherPortlet()

Method Detail

setDetectAllHandlerMappings

public void setDetectAllHandlerMappings(boolean detectAllHandlerMappings)

Set whether to detect all HandlerMapping beans in this portlet's context. Else, just a single bean with name "handlerMapping" will be expected.

Default is true. Turn this off if you want this portlet to use a single HandlerMapping, despite multiple HandlerMapping beans being defined in the context.

setDetectAllHandlerAdapters

public void setDetectAllHandlerAdapters(boolean detectAllHandlerAdapters)

Set whether to detect all HandlerAdapter beans in this portlet's context. Else, just a single bean with name "handlerAdapter" will be expected.

Default is "true". Turn this off if you want this portlet to use a single HandlerAdapter, despite multiple HandlerAdapter beans being defined in the context.

setDetectAllHandlerExceptionResolvers

public void setDetectAllHandlerExceptionResolvers(boolean detectAllHandlerExceptionResolvers)

Set whether to detect all HandlerExceptionResolver beans in this portlet's context. Else, just a single bean with name "handlerExceptionResolver" will be expected.

Default is true. Turn this off if you want this portlet to use a single HandlerExceptionResolver, despite multiple HandlerExceptionResolver beans being defined in the context.

setDetectAllViewResolvers

public void setDetectAllViewResolvers(boolean detectAllViewResolvers)

Set whether to detect all ViewResolver beans in this portlet's context. Else, just a single bean with name "viewResolver" will be expected.

Default is true. Turn this off if you want this portlet to use a single ViewResolver, despite multiple ViewResolver beans being defined in the context.

setViewRendererUrl

public void setViewRendererUrl(String viewRendererUrl)

Set the URL to the ViewRendererServlet. That servlet is used to ultimately render all views in the portlet application.

setThreadContextInheritable

public void setThreadContextInheritable(boolean threadContextInheritable)

Set whether to expose the LocaleContext and RequestAttributes as inheritable for child threads (using an InheritableThreadLocal).

Default is "false", to avoid side effects on spawned background threads. Switch this to "true" to enable inheritance for custom child threads which are spawned during request processing and only used for this request (that is, ending after their initial task, without reuse of the thread).

WARNING: Do not use inheritance for child threads if you are accessing a thread pool which is configured to potentially add new threads on demand (e.g. a JDK ThreadPoolExecutor), since this will expose the inherited context to such a pooled thread.

onRefresh

public void onRefresh(ApplicationContext context)

This implementation calls initStrategies(org.springframework.context.ApplicationContext).

Overrides:

onRefresh in class FrameworkPortlet

Parameters:

context - the current Portlet ApplicationContext

See Also:

FrameworkPortlet.refresh()

initStrategies

protected void initStrategies(ApplicationContext context)

Refresh the strategy objects that this portlet uses.

May be overridden in subclasses in order to initialize further strategy objects.

getDefaultStrategy

protected Object getDefaultStrategy(ApplicationContext context,
                                    Class strategyInterface)
                             throws BeansException

Return the default strategy object for the given strategy interface.

The default implementation delegates to getDefaultStrategies(org.springframework.context.ApplicationContext, java.lang.Class), expecting a single object in the list.

Parameters:

context - the current Portlet ApplicationContext

strategyInterface - the strategy interface

Returns:

the corresponding strategy object

Throws:

BeansException - if initialization failed

See Also:

getDefaultStrategies(org.springframework.context.ApplicationContext, java.lang.Class)

getDefaultStrategies

protected List getDefaultStrategies(ApplicationContext context,
                                    Class strategyInterface)
                             throws BeansException

Create a List of default strategy objects for the given strategy interface.

The default implementation uses the "DispatcherPortlet.properties" file (in the same package as the DispatcherPortlet class) to determine the class names. It instantiates the strategy objects and satisifies ApplicationContextAware if necessary.

Parameters:

context - the current Portlet ApplicationContext

strategyInterface - the strategy interface

Returns:

the List of corresponding strategy objects

Throws:

BeansException - if initialization failed

createDefaultStrategy

protected Object createDefaultStrategy(ApplicationContext context,
                                       Class clazz)
                                throws BeansException

Create a default strategy.

The default implementation uses AutowireCapableBeanFactory.createBean(java.lang.Class, int, boolean).

Parameters:

context - the current Portlet ApplicationContext

clazz - the strategy implementation class to instantiate

Returns:

the fully configured strategy instance

Throws:

BeansException - if initialization failed

See Also:

ApplicationContext.getAutowireCapableBeanFactory()

getMultipartResolver

public PortletMultipartResolver getMultipartResolver()

Obtain this portlet's PortletMultipartResolver, if any.

Returns:

the PortletMultipartResolver used by this portlet, or null if none (indicating that no multipart support is available)

doActionService

protected void doActionService(ActionRequest request,
                               ActionResponse response)
                        throws Exception

Processes the actual dispatching to the handler for action requests.

The handler will be obtained by applying the portlet's HandlerMappings in order. The HandlerAdapter will be obtained by querying the portlet's installed HandlerAdapters to find the first that supports the handler class.

Specified by:

doActionService in class FrameworkPortlet

Parameters:

request - current portlet action request

response - current portlet Action response

Throws:

Exception - in case of any kind of processing failure

See Also:

GenericPortlet.processAction(javax.portlet.ActionRequest, javax.portlet.ActionResponse)

doRenderService

protected void doRenderService(RenderRequest request,
                               RenderResponse response)
                        throws Exception

Processes the actual dispatching to the handler for render requests.

The handler will be obtained by applying the portlet's HandlerMappings in order. The HandlerAdapter will be obtained by querying the portlet's installed HandlerAdapters to find the first that supports the handler class.

Specified by:

doRenderService in class FrameworkPortlet

Parameters:

request - current portlet render request

response - current portlet render response

Throws:

Exception - in case of any kind of processing failure

See Also:

GenericPortlet.doDispatch(javax.portlet.RenderRequest, javax.portlet.RenderResponse)

buildLocaleContext

protected LocaleContext buildLocaleContext(PortletRequest request)

Build a LocaleContext for the given request, exposing the request's primary locale as current locale.

Parameters:

request - current HTTP request

Returns:

the corresponding LocaleContext

checkMultipart

protected ActionRequest checkMultipart(ActionRequest request)
                                throws MultipartException

Convert the request into a multipart request, and make multipart resolver available. If no multipart resolver is set, simply use the existing request.

Parameters:

request - current HTTP request

Returns:

the processed request (multipart wrapper if necessary)

Throws:

MultipartException

getHandler

protected HandlerExecutionChain getHandler(PortletRequest request,
                                           boolean cache)
                                    throws Exception

Return the HandlerExecutionChain for this request. Try all handler mappings in order.

Parameters:

request - current portlet request

cache - whether to cache the HandlerExecutionChain in a request attribute

Returns:

the HandlerExceutionChain, or null if no handler could be found

Throws:

Exception

noHandlerFound

protected void noHandlerFound(PortletRequest request,
                              PortletResponse response)
                       throws PortletException

No handler found -> throw appropriate exception.

Parameters:

request - current portlet request

response - current portlet response

Throws:

PortletException - if preparing the response failed

getHandlerAdapter

protected HandlerAdapter getHandlerAdapter(Object handler)
                                    throws PortletException

Return the HandlerAdapter for this handler object.

Parameters:

handler - the handler object to find an adapter for

Throws:

PortletException - if no HandlerAdapter can be found for the handler. This is a fatal error.

processHandlerException

protected ModelAndView processHandlerException(RenderRequest request,
                                               RenderResponse response,
                                               Object handler,
                                               Exception ex)
                                        throws Exception

Determine an error ModelAndView via the registered HandlerExceptionResolvers.

Parameters:

request - current portlet request

response - current portlet response

handler - the executed handler, or null if none chosen at the time of the exception (for example, if multipart resolution failed)

ex - the exception that got thrown during handler execution

Returns:

a corresponding ModelAndView to forward to

Throws:

Exception - if no error ModelAndView found

render

protected void render(ModelAndView mv,
                      RenderRequest request,
                      RenderResponse response)
               throws Exception

Render the given ModelAndView. This is the last stage in handling a request. It may involve resolving the view by name.

Parameters:

mv - the ModelAndView to render

request - current portlet render request

response - current portlet render response

Throws:

Exception - if there's a problem rendering the view

resolveViewName

protected View resolveViewName(String viewName,
                               Map model,
                               RenderRequest request)
                        throws Exception

Resolve the given view name into a View object (to be rendered).

Default implementations asks all ViewResolvers of this dispatcher. Can be overridden for custom resolution strategies, potentially based on specific model attributes or request parameters.

Parameters:

viewName - the name of the view to resolve

model - the model to be passed to the view

request - current portlet render request

Returns:

the View object, or null if none found

Throws:

Exception - if the view cannot be resolved (typically in case of problems creating an actual View object)

See Also:

ViewResolver.resolveViewName(java.lang.String, java.util.Locale)