updated config, added switchUserProcessingFilter to the filter chain, added the ROLE_SUPERVISOR the ability to switch to other users (i.e. ROLE_USER)

For example: 'marissa' can login,  goto the /switchUser.jsp, then assume the role of another user such as 'scott'. marissa will then see scotts contacts, etc.
Then marissa can goto the /exitUser.jsp, and go back to 'marissa'

This is the similar to the Unix 'su' analogy that Ben made

samples/contacts/src/main/webapp/filter/WEB-INF/applicationContext-acegi-security.xml

@@ -21,7 +21,7 @@
          <value>
 		    CONVERT_URL_TO_LOWERCASE_BEFORE_COMPARISON
 		    PATTERN_TYPE_APACHE_ANT
-            /**=httpSessionContextIntegrationFilter,authenticationProcessingFilter,basicProcessingFilter,rememberMeProcessingFilter,anonymousProcessingFilter,securityEnforcementFilter
+            /**=httpSessionContextIntegrationFilter,authenticationProcessingFilter,basicProcessingFilter,rememberMeProcessingFilter,anonymousProcessingFilter,securityEnforcementFilter,switchUserProcessingFilter
          </value>
       </property>
     </bean>
@@ -174,6 +174,8 @@
 			    /index.jsp=ROLE_ANONYMOUS,ROLE_USER
 			    /hello.htm=ROLE_ANONYMOUS,ROLE_USER
 			    /logoff.jsp=ROLE_ANONYMOUS,ROLE_USER
+			    /switchuser.jsp=ROLE_SUPERVISOR
+			    /j_acegi_switch_user=ROLE_SUPERVISOR
 			    /acegilogin.jsp*=ROLE_ANONYMOUS,ROLE_USER
 				/**=ROLE_USER
          </value>
@@ -182,11 +184,12 @@
 
    <!-- Filter used to switch the user context. Note: the switch and exit url must be secured 
         based on the role granted the ability to 'switch' to another user -->
+   <!-- In this example 'marissa' has ROLE_SUPERVISOR that can switch to regular ROLE_USER(s) -->
    <bean id="switchUserProcessingFilter" class="net.sf.acegisecurity.ui.switchuser.SwitchUserProcessingFilter">
       <property name="authenticationDao" ref="jdbcDaoImpl" />
 	  <property name="switchUserUrl"><value>/j_acegi_switch_user</value></property>
 	  <property name="exitUserUrl"><value>/j_acegi_exit_user</value></property>
-	  <property name="targetUrl"><value>/secure/index.htm</value></property>
+	  <property name="targetUrl"><value>/acegi-security-sample-contacts-filter/secure/index.htm</value></property>
    </bean>    
 
 </beans>