public interface EventFilter extends PortletFilter
EventFilteris an object that performs filtering tasks on either the event request to a portlet, or on the event response from a portlet, or both.
Filters perform filtering in the
doFilter method. Every Filter has
access to a
FilterConfig object from which it can obtain
its initialization parameters, a reference to the PortletContext
which it can use, for example, to load resources needed for filtering tasks.
Filters are configured in the portlet deployment descriptor of a portlet application.
|Modifier and Type||Method and Description|
void doFilter(EventRequest request, EventResponse response, FilterChain chain) throws IOException, PortletException
doFiltermethod of the Filter is called by the portlet container each time a event request/response pair is passed through the chain due to a client request for a portlet method at the end of the chain.
FilterChain passed in to this method allows
the Filter to pass on the event request and response to the next
component in the chain.
doFilter method of a filter will typically be implemented
following this or some subset of the following pattern:
ActionRequestWrapperin order to modify request data.
doFiltermethod with a customized implementation of the response wrapper
ActionResponseWrapperto modify response data.
doFiltermethod on the
FilterChainobject, and passing in the request and response with which it was called or passing in wrapped versions it may have created. The filter chain's implementation of the
doFiltermethod, provided by the portlet container, must locate the next component in the filter chain and invoke its
doFiltermethod, passing in the appropriate request and response objects. Alternatively, the filter chain can block the request by not making the call to invoke the next component, leaving the filter responsible for filling out the response object.
doFilterprocessing, the portlet container must not attempt continued processing down the filter chain. It may choose to retry the whole chain at a later time if the exception is not marked permanent.
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