| org.springframework.web.portlet.HandlerInterceptor
All known Subclasses: org.springframework.web.portlet.handler.HandlerInterceptorAdapter, org.springframework.web.portlet.handler.WebRequestHandlerInterceptorAdapter,
| HandlerInterceptor | | public interface HandlerInterceptor (Code) | | Workflow interface that allows for customized handler execution chains.
Applications can register any number of existing or custom interceptors
for certain groups of handlers, to add common preprocessing behavior
without needing to modify each handler implementation.
A HandlerInterceptor gets called before the appropriate
org.springframework.web.portlet.HandlerAdapter triggers the
execution of the handler itself. This mechanism can be used for a large
field of preprocessing aspects, e.g. for authorization checks,
or common handler behavior like locale or theme changes. Its main purpose
is to permit the factoring out of otherwise repetitive handler code.
Typically an interceptor chain is defined per
org.springframework.web.portlet.HandlerMapping bean, sharing its
granularity. To be able to apply a certain interceptor chain to a group of
handlers, one needs to map the desired handlers via one
HandlerMapping bean. The interceptors themselves are defined as
beans in the application context, referenced by the mapping bean definition
via its
org.springframework.web.portlet.handler.AbstractHandlerMapping.setInterceptors "interceptors" property (in XML: a <list> of <ref> elements).
A HandlerInterceptor is basically similar to a Servlet 2.3
javax.servlet.Filter , but in contrast to the latter it allows
custom pre-processing with the option to prohibit the execution of the handler
itself, and custom post-processing. Filters are more powerful;
for example they allow for exchanging the request and response objects that
are handed down the chain. Note that a filter gets configured in
web.xml, a HandlerInterceptor in the application context.
As a basic guideline, fine-grained handler-related preprocessing tasks are
candidates for HandlerInterceptor implementations, especially
factored-out common handler code and authorization checks. On the other hand,
a Filter is well-suited for request content and view content
handling, like multipart forms and GZIP compression. This typically shows when
one needs to map the filter to certain content types (e.g. images), or to all
requests. Be aware that filters cannot be applied to portlet requests (they
only operate on servlet requests), so for portlet requests interceptors are
essential.
If we assume a "sunny day" request (i.e. a request where nothing goes wrong
and all is well), the workflow of a HandlerInterceptor will be as
follows:
- (
DispatcherServlet maps a request to particular handler
and assembles a handler execution chain consisting of the handler that
is to be invoked and all of the HandlerInterceptor
instances that apply to the request.)
-
org.springframework.web.portlet.HandlerInterceptor.preHandleAction(javax.portlet.ActionRequestjavax.portlet.ActionResponseObject) preHandleAction(..) is called; if the invocation of this method returns
true then
this workflow continues
- The target handler handles the action phase of the request (via
org.springframework.web.portlet.HandlerAdapter.handleAction(javax.portlet.ActionRequestjavax.portlet.ActionResponseObject) HandlerAdapter.handleAction(..) )
-
org.springframework.web.portlet.HandlerInterceptor.afterActionCompletion(javax.portlet.ActionRequestjavax.portlet.ActionResponseObjectException) afterActionCompletion(..) is called
-
org.springframework.web.portlet.HandlerInterceptor.preHandleRender(javax.portlet.RenderRequestjavax.portlet.RenderResponseObject) preHandleRender(..) is called; if the invocation of this method returns
true then
this workflow continues
- The target handler handles the render phase of the request (via
org.springframework.web.portlet.HandlerAdapter.handleRender(javax.portlet.RenderRequestjavax.portlet.RenderResponseObject) HandlerAdapter.handleRender(..) )
-
org.springframework.web.portlet.HandlerInterceptor.postHandleRender(javax.portlet.RenderRequestjavax.portlet.RenderResponseObjectModelAndView) postHandleRender(..) is called
-
org.springframework.web.portlet.HandlerInterceptor.afterRenderCompletion(javax.portlet.RenderRequestjavax.portlet.RenderResponseObjectException) afterRenderCompletion(..) is called
author:
Juergen Hoeller
author:
John A. Lewis
since:
2.0
See Also: HandlerExecutionChain.getInterceptors
See Also: org.springframework.web.portlet.HandlerMapping
See Also: org.springframework.web.portlet.handler.AbstractHandlerMapping.setInterceptors
See Also: org.springframework.web.portlet.HandlerExecutionChain |
| Method Summary | |
| void | afterActionCompletion(ActionRequest request, ActionResponse response, Object handler, Exception ex)
Callback after completion of request processing in the action phase, that is,
after rendering the view. | | void | afterRenderCompletion(RenderRequest request, RenderResponse response, Object handler, Exception ex)
Callback after completion of request processing, that is, after rendering
the view. | | void | postHandleRender(RenderRequest request, RenderResponse response, Object handler, ModelAndView modelAndView)
Intercept the execution of a handler in the render phase.
Called after a
HandlerAdapter actually invoked the handler, but
before the DispatcherPortlet renders the view. | | boolean | preHandleAction(ActionRequest request, ActionResponse response, Object handler)
Intercept the execution of a handler in the action phase.
Called after a HandlerMapping determines an appropriate handler object
to handle an
ActionRequest , but before said HandlerAdapter actually
invokes the handler.
DispatcherPortlet processes a handler in an execution chain,
consisting of any number of interceptors, with the handler itself at the end.
With this method, each interceptor can decide to abort the execution chain,
typically throwing an exception or writing a custom response.
Parameters:
request - current portlet action request
Parameters:
response - current portlet action response
Parameters:
handler - chosen handler to execute, for type and/or instance evaluation true if the execution chain should proceed with thenext interceptor or the handler itself. | | boolean | preHandleRender(RenderRequest request, RenderResponse response, Object handler)
Intercept the execution of a handler in the render phase.
Called after a HandlerMapping determines an appropriate handler object
to handle a
RenderRequest , but before said HandlerAdapter actually
invokes the handler.
DispatcherPortlet processes a handler in an execution chain,
consisting of any number of interceptors, with the handler itself at the end.
With this method, each interceptor can decide to abort the execution chain,
typically throwing an exception or writing a custom response.
Parameters:
request - current portlet render request
Parameters:
response - current portlet render response
Parameters:
handler - chosen handler to execute, for type and/or instance evaluation true if the execution chain should proceed with thenext interceptor or the handler itself. |
| afterActionCompletion | | void afterActionCompletion(ActionRequest request, ActionResponse response, Object handler, Exception ex) throws Exception(Code) | | Callback after completion of request processing in the action phase, that is,
after rendering the view. Will be called on any outcome of handler execution,
thus allowing for proper resource cleanup.
Note: Will only be called if this interceptor's
HandlerInterceptor.preHandleAction(javax.portlet.ActionRequest,javax.portlet.ActionResponse,Object) method has successfully completed and returned true!
Parameters:
request - current portlet action request
Parameters:
response - current portlet action response
Parameters:
handler - chosen handler to execute, for type and/or instance examination
Parameters:
ex - exception thrown on handler execution, if any (only included asadditional context information for the case where a handler threw an exception;request execution may have failed even when this argument is null)
throws:
Exception - in case of errors |
| afterRenderCompletion | | void afterRenderCompletion(RenderRequest request, RenderResponse response, Object handler, Exception ex) throws Exception(Code) | | Callback after completion of request processing, that is, after rendering
the view. Will be called on any outcome of handler execution, thus allowing
for proper resource cleanup.
Note: Will only be called if this interceptor's
HandlerInterceptor.preHandleRender(javax.portlet.RenderRequest,javax.portlet.RenderResponse,Object) method has successfully completed and returned true!
Parameters:
request - current portlet render request
Parameters:
response - current portlet render response
Parameters:
handler - chosen handler to execute, for type and/or instance examination
Parameters:
ex - exception thrown on handler execution, if any
throws:
Exception - in case of errors |
| postHandleRender | | void postHandleRender(RenderRequest request, RenderResponse response, Object handler, ModelAndView modelAndView) throws Exception(Code) | | Intercept the execution of a handler in the render phase.
Called after a
HandlerAdapter actually invoked the handler, but
before the DispatcherPortlet renders the view. Can thus expose
additional model objects to the view via the given
ModelAndView .
DispatcherPortlet processes a handler in an execution chain,
consisting of any number of interceptors, with the handler itself at the end.
With this method, each interceptor can post-process an execution, getting
applied in inverse order of the execution chain.
Parameters:
request - current portlet render request
Parameters:
response - current portlet render response
Parameters:
handler - chosen handler to execute, for type and/or instance examination
Parameters:
modelAndView - the ModelAndView that the handler returned(can also be null)
throws:
Exception - in case of errors
|
| preHandleAction | | boolean preHandleAction(ActionRequest request, ActionResponse response, Object handler) throws Exception(Code) | | Intercept the execution of a handler in the action phase.
Called after a HandlerMapping determines an appropriate handler object
to handle an
ActionRequest , but before said HandlerAdapter actually
invokes the handler.
DispatcherPortlet processes a handler in an execution chain,
consisting of any number of interceptors, with the handler itself at the end.
With this method, each interceptor can decide to abort the execution chain,
typically throwing an exception or writing a custom response.
Parameters:
request - current portlet action request
Parameters:
response - current portlet action response
Parameters:
handler - chosen handler to execute, for type and/or instance evaluation true if the execution chain should proceed with thenext interceptor or the handler itself. Else, DispatcherPortletassumes that this interceptor has already dealt with the response itself
throws:
Exception - in case of errors |
| preHandleRender | | boolean preHandleRender(RenderRequest request, RenderResponse response, Object handler) throws Exception(Code) | | Intercept the execution of a handler in the render phase.
Called after a HandlerMapping determines an appropriate handler object
to handle a
RenderRequest , but before said HandlerAdapter actually
invokes the handler.
DispatcherPortlet processes a handler in an execution chain,
consisting of any number of interceptors, with the handler itself at the end.
With this method, each interceptor can decide to abort the execution chain,
typically throwing an exception or writing a custom response.
Parameters:
request - current portlet render request
Parameters:
response - current portlet render response
Parameters:
handler - chosen handler to execute, for type and/or instance evaluation true if the execution chain should proceed with thenext interceptor or the handler itself. Else, DispatcherPortletassumes that this interceptor has already dealt with the response itself
throws:
Exception - in case of errors |
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