W E B   S E R V I C E S  

            > 

You will also find some useful tips on the Jetty website at 

http://jetty.mortbay.org/jetty/doc/SslListener.html

Using JAAS 

JAAS support is configurable across the JettyService instance via specifying the JAAS name 

of the attribute in which the active subject is transported: 

       j_subject 

Using Distributed HttpSessions 

What distribution means 

An 

HttpSession

  is an object used in a webapp to store conversational state between 

requests. It is configured in the webapp by specifying  distributable  in it s 

WEB 

INF/web.xml

. 

The J2EE specification requires that a  distributable  app may be  migrated  between nodes 

of a cluster   i.e. taken down on one node and brought up on another. Extant 

HttpSession

s 

must continue to be available to the new webapp instance. Many appservers extend this 

functionality from simply allowing migration to providing failover i.e. if a webapp is not 

undeployed from it s node cleanly (eg the  node crashes, hangs, becomes overloaded) it s 

HttpSessions

 are still made available to other instances of the same webapp within the 

cluster. 

This extension is problematic since J2EE requires that on being undeployed, a distributed 

webapp should notify 

HttpSession

 attributes implementing 

HttpSessionActivationListener

 before passivating/distributing them. When the 

webapp has been re deployed and it re activates an 

HttpSession

, the same attributes must 

be notified again. If, because of the reuse of this functionality to provide fail over, attributes 

do not receive passivation events on one node before receipt of activation events on another, 

an asymmetry   which would not happen on a fully compliant appserver   occurs. 

The Jetty integration allows the user to specify whether this extended behaviour (called 

 snapshotting ) is required and, if so, exactly what combination of events attributes should 

expect. 

Configuring it 

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