DelegatingPluginFilter We wrap the plugins filter so that we can set some things up before the plugins filter is called. 
IteratingFilterChain This FilterChain passes control from the first Filter in an iterator to the last. 
PluginFilterConfig Instances of the PluginFilterConfig are passed to plugins Filter init() method. 
ServletFilterModuleContainerFilter Applications need to create a concrete subclass of this for use in their filter stack. 


FilterDispatcherCondition The dispatching conditions that are taken into account when deciding to match a filter. 
FilterLocation An enumeration defining the places plugin filters can appear in an applications filter stack.