Hi Simon! Thanks for all the hard work you put into documentation and cleanup of the Orchestra API. This really brings the project even further!
Have a nice Weekend! Ciao, Mario [EMAIL PROTECTED] schrieb: > Author: skitching > Date: Fri Aug 17 04:19:22 2007 > New Revision: 567017 > > URL: http://svn.apache.org/viewvc?view=rev&rev=567017 > Log: > Add javadoc only. > > Modified: > > myfaces/orchestra/trunk/core/src/main/java/org/apache/myfaces/orchestra/conversation/jsf/filter/OrchestraServletFilter.java > > Modified: > myfaces/orchestra/trunk/core/src/main/java/org/apache/myfaces/orchestra/conversation/jsf/filter/OrchestraServletFilter.java > URL: > http://svn.apache.org/viewvc/myfaces/orchestra/trunk/core/src/main/java/org/apache/myfaces/orchestra/conversation/jsf/filter/OrchestraServletFilter.java?view=diff&rev=567017&r1=567016&r2=567017 > ============================================================================== > --- > myfaces/orchestra/trunk/core/src/main/java/org/apache/myfaces/orchestra/conversation/jsf/filter/OrchestraServletFilter.java > (original) > +++ > myfaces/orchestra/trunk/core/src/main/java/org/apache/myfaces/orchestra/conversation/jsf/filter/OrchestraServletFilter.java > Fri Aug 17 04:19:22 2007 > @@ -33,14 +33,46 @@ > import javax.servlet.http.HttpServletResponse; > import java.io.IOException; > > +/** > + * Ensures that only one request per conversationContext can be processed at > a time, > + * and also ensure all JDBC connections are returned to the pool. > + * <p> > + * <h2>Request Synchronization</h2> > + * It is possible for multiple requests associated with the same http > session to be > + * received concurrently. In particular, ajax pages can cause this. > + * <p> > + * By default, the servlet engine simply processes all requests concurrently > + * in different threads. However that can cause all sorts of unexpected > problems with > + * session-scoped objects. > + * <p> > + * The usual solution is to apply a filter to all requests which uses > standard java > + * synchronisation on a session-scoped object, taking the lock on request > entry and > + * releasing it on request exit. This ensures that only one request for that > session > + * runs at a time, with the others waiting until they can obtain a lock on > the > + * appropriate object. > + * <p> > + * When using an Orchestra conversationContext, session-scoped data should > be avoided and > + * conversation-scoped beans used instead. If there is no session-scoped > data in use by > + * an application then it is possible to allow concurrent requests to the > same http session, > + * but NOT concurrent access to the same orchestra conversationContext. This > filter > + * implements that, by holding a lock on a mutex object held by the > appropriate > + * conversationContext. > + * <p> > + * This filter can be enabled or disabled via a filter init parameter; > setting > + * "serializeRequests" to "false" disables this filter. Default value: true > (enabled). > + * <p> > + * <h2>JDBC Connection Management</h2> > + * Orchestra provides a special DataSource wrapper that can be configured > for any > + * datasource used by the application. The datasource simply wraps all real > Connection > + * objects it returns in a proxy, and keeps track of them. Here in this > servlet it > + * checks whether all connections borrowed by this thread have been > returned, and if > + * not returns the real connection nulls out the connection held by the > proxy. See > + * ConnectionManagerDataSource for more details. > + */ > public class OrchestraServletFilter implements Filter > { > /** > - * true|false > - * Allows to configure if Orchestra should serialize each request > against the conversationContext. > - * This means, that e.g. if multiple threads (in an ajax environment) > concurrently access the > - * conversationContext would not bother each other. > - * Default: true > + * This filter init property can be set to "true" or "false". Default: > "true". > */ > public final static String SERIALIZE_REQUESTS = "serializeRequests"; // > NON-NLS > private final static String CONTEXT_MUTEXT_OBJECT = > OrchestraServletFilter.class.getName() + ".SER_MUTEX"; > > >
