Package org.eclipse.jetty.server.handler

Class ScopedHandler

java.lang.Object
org.eclipse.jetty.util.component.AbstractLifeCycle
org.eclipse.jetty.util.component.ContainerLifeCycle
org.eclipse.jetty.server.handler.AbstractHandler
org.eclipse.jetty.server.handler.AbstractHandlerContainer
org.eclipse.jetty.server.handler.HandlerWrapper
org.eclipse.jetty.server.handler.ScopedHandler
All Implemented Interfaces:
Handler, HandlerContainer, Container, Destroyable, Dumpable, Dumpable.DumpableContainer, LifeCycle
Direct Known Subclasses:
ContextHandler, ServletHandler, SessionHandler
public abstract class ScopedHandler extends HandlerWrapper
ScopedHandler. A ScopedHandler is a HandlerWrapper where the wrapped handlers each define a scope.

When handle(String, Request, HttpServletRequest, HttpServletResponse) is called on the first ScopedHandler in a chain of HandlerWrappers, the doScope(String, Request, HttpServletRequest, HttpServletResponse) method is called on all contained ScopedHandlers, before the doHandle(String, Request, HttpServletRequest, HttpServletResponse) method is called on all contained handlers.

For example if Scoped handlers A, B & C were chained together, then the calling order would be:

 A.handle(...)
   A.doScope(...)
     B.doScope(...)
       C.doScope(...)
         A.doHandle(...)
           B.doHandle(...)
              C.doHandle(...)

If non scoped handler X was in the chained A, B, X & C, then the calling order would be:

 A.handle(...)
   A.doScope(...)
     B.doScope(...)
       C.doScope(...)
         A.doHandle(...)
           B.doHandle(...)
             X.handle(...)
               C.handle(...)
                 C.doHandle(...)

A typical usage pattern is:

     private static class MyHandler extends ScopedHandler
     {
         public void doScope(String target, HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException
         {
             try
             {
                 setUpMyScope();
                 super.doScope(target,request,response);
             }
             finally
             {
                 tearDownMyScope();
             }
         }

         public void doHandle(String target, HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException
         {
             try
             {
                 doMyHandling();
                 super.doHandle(target,request,response);
             }
             finally
             {
                 cleanupMyHandling();
             }
         }
     }