I believe my client is using Tomcat 6; I'll check.
So, at startup, the Manager reads the saved HttpSession state into
memory, then starts init'ing filters and servlets? I really need to
find a way to work on that ordering.
On Thu, May 27, 2010 at 8:43 AM, Pid <p...@pidster.com> wrote:
> On 27/05/2010 16:31, Howard Lewis Ship wrote:
>> I have a question, on behalf of a client, concerning Tomcat clustering
>> and deserialization, in the context of a Tapestry 5 application.
>>
>> Here's the short form: some of the objects that a Tapestry
>> application may put into the HttpSession will only deserialize
>> correctly
>> if the Tapestry application (in the form of a Servlet Filter) has
>> initialized first ... but it appears that when starting up a Tomcat
>> instance,
>> the HttpSession data is deserialized from disk *before* the filter is
>> initialized.
>
> Is there a specific Tomcat version you're targeting?
>
> Session persistence is a Manager Valve function, so AFAIK the
> deserialisation will occur before Filters (or any other web app stuff,
> like ServletContextListeners) are started.
>
>
> p
>
>
>> Here's the stack trace:
>>
>> ERROR ( ManagerBase:412 ) - IOException while loading
>> persisted sessions: java.io.InvalidObjectException: Service token for
>> service 'ProductConfig' can not be converted back into a proxy because
>> no proxy provider has been registered. This may indicate that an IoC
>> Registry has not been started yet.
>> java.io.InvalidObjectException: Service token for service
>> 'ProductConfig' can not be converted back into a proxy because no
>> proxy provider has been registered. This may indicate that an IoC
>> Registry has not been started yet.
>> at
>> org.apache.tapestry5.ioc.internal.ServiceProxyToken.readResolve(ServiceProxyToken.java:41)
>> at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
>> at
>> sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
>> at
>> sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
>> at java.lang.reflect.Method.invoke(Method.java:597)
>> at
>> java.io.ObjectStreamClass.invokeReadResolve(ObjectStreamClass.java:1061)
>> at
>> java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1762)
>> at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1329)
>> at
>> java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:1947)
>> at
>> java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1871)
>> at
>> java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1753)
>> at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1329)
>> at java.io.ObjectInputStream.readObject(ObjectInputStream.java:351)
>> at
>> org.apache.catalina.session.StandardSession.readObject(StandardSession.java:1407)
>> at
>> org.apache.catalina.session.StandardSession.readObjectData(StandardSession.java:931)
>> at
>> org.apache.catalina.session.StandardManager.doLoad(StandardManager.java:394)
>> at
>> org.apache.catalina.session.StandardManager.load(StandardManager.java:321)
>> at
>> org.apache.catalina.session.StandardManager.start(StandardManager.java:637)
>> at
>> org.apache.catalina.core.ContainerBase.setManager(ContainerBase.java:432)
>> at
>> org.apache.catalina.core.StandardContext.start(StandardContext.java:4160)
>> at
>> org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1014)
>> at org.apache.catalina.core.StandardHost.start(StandardHost.java:736)
>> at
>> org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1014)
>> at
>> org.apache.catalina.core.StandardEngine.start(StandardEngine.java:443)
>> at
>> org.apache.catalina.core.StandardService.start(StandardService.java:448)
>> at
>> org.apache.catalina.core.StandardServer.start(StandardServer.java:700)
>> at org.apache.catalina.startup.Catalina.start(Catalina.java:552)
>> at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
>> at
>> sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
>> at
>> sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
>> at java.lang.reflect.Method.invoke(Method.java:597)
>> at org.apache.catalina.startup.Bootstrap.start(Bootstrap.java:295)
>> at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:433)
>> Caused by: java.lang.RuntimeException: Service token for service
>> 'ProductConfig' can not be converted back into a proxy because no
>> proxy provider has been registered. This may indicate that an IoC
>> Registry has not been started yet.
>> at
>> org.apache.tapestry5.ioc.internal.SerializationSupport.readResolve(SerializationSupport.java:72)
>> at
>> org.apache.tapestry5.ioc.internal.ServiceProxyToken.readResolve(ServiceProxyToken.java:37)
>>
>>
>> The failure occurs inside this code:
>>
>> class ServiceProxyToken implements Serializable
>> {
>> private final String serviceId;
>>
>> ServiceProxyToken(String serviceId)
>> {
>> this.serviceId = serviceId;
>> }
>>
>> Object readResolve() throws ObjectStreamException
>> {
>> try
>> {
>> return SerializationSupport.readResolve(serviceId);
>> }
>> catch (Exception ex)
>> {
>> ObjectStreamException ose = new
>> InvalidObjectException(ex.getMessage());
>> ose.initCause(ex);
>>
>> throw ose;
>> }
>> }
>>
>> }
>>
>> This occurs because the Tapestry IoC container has not been
>> initialized by the Tapestry Filter yet.
>> SerializationSupport.readResolve() requires that the Filter be
>> initialized.
>>
>> In case you are curious: these ServiceProxyToken objects are
>> placeholder for Tapestry IoC services. In Tapestry IoC, every service
>> implements an interface, and is exposed to user code as an instance of
>> a proxy. The proxy hides the lifecycle of the service (i.e., to
>> support just-in-time instantiation), and the proxy is Serializable
>> where the actual service implementation class is not.
>>
>> Sometimes an HttpSession object will hold a reference to a Tapestry
>> service. When serialized, the proxy serializes a ServiceProxyToken.
>> When that's deserialized, we get back an equivalent service in the new
>> server.
>>
>> So ... is there a configuration option somewhere to defer loading of
>> the HttpSession until after the filters are instantiated? Is there
>> some other mechanism that will support what I want to do?
>>
>> Alternately, I'd appreciate some pointers on what code would need to
>> be modified to support this scenario. It makes a big difference to
>> Tapestry 5 users who use Tomcat clustering!
>>
>>
>
>
>
--
Howard M. Lewis Ship
Creator of Apache Tapestry
The source for Tapestry training, mentoring and support. Contact me to
learn how I can get you up and productive in Tapestry fast!
(971) 678-5210
http://howardlewisship.com
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