Because I consider some of the “features” of the latest 2.4 specification rather dubious or expensive,
I was reluctant to implement them as core features of Jetty. Instead, Jetty 5.1 will use optional
filters to provide JSR77 statistics, wrap under dispatch semantics, request events and request attribute
events.
Thus Jetty is able to support these features needed for specification compliance, but they can
be simply removed with no lingering classpath dependencies simply be removing the filters.
While this demonstrates the power of filters, it has also revealed a missing filter mapping in
the specification. There is no way to define a filter to intercept ALL dispatches in a webapplication.
A Filter mapped to / for REQUEST,FORWARD,INCLUDE and ERROR comes close, but is unable to filter
named dispatches. Named dispatches can be filtered with filters mapped to a servlet name, but it
is not possible to generically map a filter to all servlets. Something for the 2.5 spec…

Missing Filter Mapping.