org.springframework.web.portlet.HandlerInterceptor |
Known Indirect Subclasses |
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 pre-processing behavior without needing to modify each handler implementation.
A HandlerInterceptor
gets called before the appropriate
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
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
"interceptors"
property (in XML: a <list> of <ref> elements).
A HandlerInterceptor
is basically similar to a Servlet
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 pre-processing 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 cycle (i.e. a request where nothing goes wrong
and all is well), the workflow of a HandlerInterceptor
will be as
follows:
Action Request:
DispatcherPortlet
maps the action request to a 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.true
then
this workflow continuesRender Request:
DispatcherPortlet
maps the render request to a 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.true
then
this workflow continuesHandlerAdapter
returned a ModelAndView
,
then DispatcherPortlet
renders the view accordingly
Public Methods | |||||||||||
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Callback after completion of request processing in the action phase, that is,
after rendering the view.
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Callback after completion of request processing in the action phase, that is,
after rendering the view.
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Callback after completion of request processing, that is, after rendering
the view.
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Callback after completion of request processing, that is, after rendering
the view.
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Intercept the execution of a handler in the render phase.
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Intercept the execution of a handler in the render phase.
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Intercept the execution of a handler in the action phase.
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Intercept the execution of a handler in the action phase.
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Intercept the execution of a handler in the render phase.
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Intercept the execution of a handler in the render phase.
|
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
#preHandleAction(javax.portlet.ActionRequest, javax.portlet.ActionResponse, Object)
method has successfully completed and returned true
!
request | current portlet action request |
---|---|
response | current portlet action response |
handler | chosen handler to execute, for type and/or instance examination |
ex | exception thrown on handler execution, if any (only included as
additional context information for the case where a handler threw an exception;
request execution may have failed even when this argument is null ) |
Exception | in case of errors |
---|
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
#preHandleAction(javax.portlet.ActionRequest, javax.portlet.ActionResponse, Object)
method has successfully completed and returned true
!
request | current portlet action request |
---|---|
response | current portlet action response |
handler | chosen handler to execute, for type and/or instance examination |
ex | exception thrown on handler execution, if any (only included as
additional context information for the case where a handler threw an exception;
request execution may have failed even when this argument is null ) |
Exception | in case of errors |
---|
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
#preHandleRender(javax.portlet.RenderRequest, javax.portlet.RenderResponse, Object)
method has successfully completed and returned true
!
request | current portlet render request |
---|---|
response | current portlet render response |
handler | chosen handler to execute, for type and/or instance examination |
ex | exception thrown on handler execution, if any |
Exception | in case of errors |
---|
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
#preHandleRender(javax.portlet.RenderRequest, javax.portlet.RenderResponse, Object)
method has successfully completed and returned true
!
request | current portlet render request |
---|---|
response | current portlet render response |
handler | chosen handler to execute, for type and/or instance examination |
ex | exception thrown on handler execution, if any |
Exception | in case of errors |
---|
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.
request | current portlet render request |
---|---|
response | current portlet render response |
handler | chosen handler to execute, for type and/or instance examination |
modelAndView | the ModelAndView that the handler returned
(can also be null ) |
Exception | in case of errors |
---|
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.
request | current portlet render request |
---|---|
response | current portlet render response |
handler | chosen handler to execute, for type and/or instance examination |
modelAndView | the ModelAndView that the handler returned
(can also be null ) |
Exception | in case of errors |
---|
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.
request | current portlet action request |
---|---|
response | current portlet action response |
handler | chosen handler to execute, for type and/or instance evaluation |
true
if the execution chain should proceed with the
next interceptor or the handler itself. Else, DispatcherPortlet
assumes that this interceptor has already dealt with the response itselfException | in case of errors |
---|
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.
request | current portlet action request |
---|---|
response | current portlet action response |
handler | chosen handler to execute, for type and/or instance evaluation |
true
if the execution chain should proceed with the
next interceptor or the handler itself. Else, DispatcherPortlet
assumes that this interceptor has already dealt with the response itselfException | in case of errors |
---|
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.
request | current portlet render request |
---|---|
response | current portlet render response |
handler | chosen handler to execute, for type and/or instance evaluation |
true
if the execution chain should proceed with the
next interceptor or the handler itself. Else, DispatcherPortlet
assumes that this interceptor has already dealt with the response itselfException | in case of errors |
---|
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.
request | current portlet render request |
---|---|
response | current portlet render response |
handler | chosen handler to execute, for type and/or instance evaluation |
true
if the execution chain should proceed with the
next interceptor or the handler itself. Else, DispatcherPortlet
assumes that this interceptor has already dealt with the response itselfException | in case of errors |
---|