Return-Path: <thomas.cherel@ascentialsoftware.com>
Mailing-List: contact axis-user-help@xml.apache.org; run by ezmlm
Delivered-To: mailing list axis-user@xml.apache.org
Received: (qmail 47180 invoked from network); 14 Jun 2002 14:26:01 -0000
Received: from web.ardentsoftware.com (HELO asc-bh-01.ascentialsoftware.com)
 (4.21.160.3)
  by daedalus.apache.org with SMTP; 14 Jun 2002 14:26:01 -0000
Received: by asc-bh-01.ascentialsoftware.com with Internet Mail Service
 (5.5.2653.19)
	id <MY99NXSM>; Fri, 14 Jun 2002 10:29:16 -0400
Message-ID: <A97C7354105F2B4C82C705D351F2BF4704E20DF0@asc-msg-01>
From: thomas.cherel@ascentialsoftware.com
To: axis-user@xml.apache.org
Subject: RE: Exposing EJBs as web services...
Date: Fri, 14 Jun 2002 10:29:07 -0400
MIME-Version: 1.0
X-Mailer: Internet Mail Service (5.5.2653.19)
Content-Type: multipart/alternative;
	boundary="----_=_NextPart_001_01C213AF.D7A36750"
X-Spam-Rating: daedalus.apache.org 1.6.2 0/1000/N

This message is in MIME format. Since your mail reader does not understand
this format, some or all of this message may not be legible.

------_=_NextPart_001_01C213AF.D7A36750
Content-Type: text/plain;
	charset="ISO-8859-1"


I played with the EJB as web service quite a bit with Axis. Here is the
result of my findings:

1) With Axis you can configure which methods are exposed when you deploy the
web service. In the EJB case, what you expose to the web service client is
the remote interface (Axis server act as the EJB client). You can decide to
expose the methods inherited from EJBObject by the remote interface if you
want to.

2) Axis session (when service is declared with a session scope in the wsdd)
are maintained by caching the web service implementation object using the
HTTPSession object. For the EJB, it means that the EJB client object (Axis
server act as the EJBClient) is the object which is cached. But the current
EJBProvider has no support for any kind of EJB error recovery. If the EJB
session is timing out, your web service in the current web service session
is broken. You have no way form the web service client to ask Axis to
"refresh" the cached service implementation object. I also tried with
stateful EJB. If a runtime exception in the stateful bean implementation is
occurring, EJB spec states that stateful bean is discarded. But Axis EJB
provider does not handle that at all (it does not try to detect runtime
exception and then discarded the cached object).

You can look at a the code of the current EJBProvider for Axis
(xml-axis-beta2/java/src/org/apache/axis/providers/java/EJBProvider.java).
It is pretty straightforward to understand. But for production application
using EJBs as web service implementation with Axis, this provider needs to
be improved.

Thomas


-----Original Message-----
From: Mark_Palmer@wildfire.com [mailto:Mark_Palmer@wildfire.com]
Sent: Friday, June 14, 2002 6:12 AM
To: axis-user@xml.apache.org
Subject: RE: Exposing EJBs as web services...



Exposing an EJB as a web service sounds very interesting.

Does anyone know how session state is maintained?  If the EJB's methods are
actually exposed to Axis clients, how is session timeout state handled?
When a session is completed (say it's a stateful session bean), how does
Axis know that the session and the bean need to be destroyed?

-Mark

--------------------------------------------------
There is no spoon.
--------------------------------------------------


 

                    "Hurst, Cyrus"

                    <Cyrus_Hurst@tvra       To:
"'axis-user@xml.apache.org'" <axis-user@xml.apache.org>      
                    tings.com>              cc:

                                            Subject:     RE: Exposing EJBs
as web services...                    
                    06/13/2002 06:02

                    PM

                    Please respond to

                    axis-user

 

 





Hello,

           To solve the NoClassDefFoundErrors I had to copy the Remote and
Home
interfaces for my EJB and any classes that the                     Remote
interface has
dependencies on into the axis/WEB-INF/classes/ directory . Once I got thru
that I kept
      getting unknown operation(on both client and server console)  on the
exposed method of the EJB . So I
      wrote and deployed  a class
       as a web-service(using provider="java:RPC")  that basically acts as
a
delegate to the EJB . I used the
       same client code to test it and it ran fine . I undeployed that
web-service and re-deployed the other
     web-service using provider ="java:EJB"  and I still get the unkown
operation on the method of the EJB.
     My deployment descriptors are as follows:

For RPC -
<deployment xmlns="http://xml.apache.org/axis/wsdd/"
           xmlns:java="http://xml.apache.org/axis/wsdd/providers/java"
           xmlns:xsi="http:/www.w3.org/2000/10/XMLSchema-instance">
           <service name="AssociateInfo" provider="java:RPC">
                     <parameter name="className" value="TestCprEJBClient"
/>
                     <parameter name="allowedMethods"
value="getAssociateIDFromDMZID" />
           </service>
</deployment>

For EJB -
<deployment xmlns="http://xml.apache.org/axis/wsdd/"
            xmlns:java="http://xml.apache.org/axis/wsdd/providers/java"
            xmlns:xsi="http:/www.w3.org/2000/10/XMLSchema-instance">
    <service name="AssociateInfo" provider="java:EJB">
        <parameter name="beanJndiName" value="jndi/ejb/AssociateSessionEJB"
/>
        <parameter name="homeInterfaceName"
value="com.nielsenmedia.lrs.cpr.associate.AssociateSessionHome" />
        <parameter name="allowedMethods" value="getAssociateIDFromDMZID"/>
        <parameter name="jndiURL" value="t3://d2loc:9023" />
        <parameter name="jndiContextClass"
value="weblogic.jndi.WLInitialContextFactory" />
    </service>
</deployment>

As you can see I'm using the same operation name for both styles . In the
delegate class(TestCprEJBClient) I use the same parameters in the EJB wsdd
to do  jndi lookup, create Home interface, etc .... Am I missing something?


Thanks,
-Cyrus




-----Original Message-----
From: thomas.cherel@ascentialsoftware.com
[mailto:thomas.cherel@ascentialsoftware.com]
Sent: Wednesday, June 12, 2002 6:01 PM
To: axis-user@xml.apache.org
Subject: RE: Exposing EJBs as web services...


Exception messages can just be serialized and passed form one client to
another.
May be trying to write an independent EJB client and making it work first
can be a good idea. It will remove the Axis piece. This EJB client should
be
able to work only with the Home and remote interface in the classpath. If
you are still getting some exceptions on the weblogic console, it means
that
your bean is not correctly deployed.
-----Original Message-----
From: Hurst, Cyrus [mailto:Cyrus_Hurst@tvratings.com]
Sent: Wednesday, June 12, 2002 5:41 PM
To: 'axis-user@xml.apache.org'
Subject: RE: Exposing EJBs as web services...


  Both ..On the client console I get :
      weblogic.rmi.extensions.RemoteRuntimeException - with nested
exception:
    [java.lang.NoClassDefFoundError:
com/nielsenmedia/lrs/cpr/common/CPREnterpriseException]
        at
org.apache.axis.message.SOAPFaultBuilder.endElement(SOAPFaultBuilder.java:13


4)
        at
org.apache.axis.encoding.DeserializationContextImpl.endElement(Deserializati


onCo
        at
org.apache.xerces.parsers.SAXParser.endElement(SAXParser.java:1403)
        at
org.apache.xerces.validators.common.XMLValidator.callEndElement(XMLValidator


.jav
        at
org.apache.xerces.framework.XMLDocumentScanner$ContentDispatcher.dispatch(XM


LDoc
        at
org.apache.xerces.framework.XMLDocumentScanner.parseSome(XMLDocumentScanner.


java
        at org.apache.xerces.framework.XMLParser.parse(XMLParser.java:1081)

        at javax.xml.parsers.SAXParser.parse(SAXParser.java:345)
        at
org.apache.axis.encoding.DeserializationContextImpl.parse(DeserializationCon


text
        at org.apache.axis.SOAPPart.getAsSOAPEnvelope(SOAPPart.java:455)
        at org.apache.axis.Message.getSOAPEnvelope(Message.java:321)
        at org.apache.axis.client.Call.invoke(Call.java:1954)
        at org.apache.axis.client.Call.invoke(Call.java:1707)
        at org.apache.axis.client.Call.invoke(Call.java:1635)
        at org.apache.axis.client.Call.invoke(Call.java:1184)
        at TestCprRpcClient.main(TestCprRpcClient.java:36)
[INFO] Call - -Mapping Exception to AxisFault
<weblogic.rmi.extensions.RemoteRuntimeExcepti
on:
[java.lang.NoClassDefFoundError:
com/nielsenmedia/lrs/cpr/common/CPREnterpriseException]>
weblogic.rmi.extensions.RemoteRuntimeException - with nested exception:
[java.lang.NoClassDefFoundError:
com/nielsenmedia/lrs/cpr/common/CPREnterpriseException]


 On the server(running Weblogic 6.1)  console I get :

   weblogic.rmi.extensions.RemoteRuntimeException - with nested exception:
[java.lang.NoClassDefFoundError:
com/nielsenmedia/lrs/cpr/common/CPREnterpriseException]
        at weblogic.rmi.internal.ProxyStub.invoke(ProxyStub.java:60)
        at $Proxy56.lookup(Unknown Source)
        at
weblogic.jndi.internal.WLContextImpl.lookup(WLContextImpl.java:323)
        at javax.naming.InitialContext.lookup(InitialContext.java:350)
        at
org.apache.axis.providers.java.EJBProvider.getEJBHome(EJBProvider.java:300)

        at
org.apache.axis.providers.java.EJBProvider.getNewServiceObject(EJBProvider.j


ava:109)
        at
org.apache.axis.providers.java.JavaProvider.getServiceObject(JavaProvider.ja


va:126)
        at
org.apache.axis.providers.java.JavaProvider.invoke(JavaProvider.java:234)
        at
org.apache.axis.strategies.InvocationStrategy.visit(InvocationStrategy.java:


71)
        at org.apache.axis.SimpleChain.doVisiting(SimpleChain.java:154)
        at org.apache.axis.SimpleChain.invoke(SimpleChain.java:121)
        at org.apache.axis.server.AxisServer.invoke(AxisServer.java:288)
        at
org.apache.axis.transport.http.AxisServlet.doPost(AxisServlet.java:576)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:760)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:853)
        at
weblogic.servlet.internal.ServletStubImpl.invokeServlet(ServletStubImpl.java


:265)
        at
weblogic.servlet.internal.ServletStubImpl.invokeServlet(ServletStubImpl.java


:200)
        at
weblogic.servlet.internal.WebAppServletContext.invokeServlet(WebAppServletCo


ntext.java:2456)
        at
weblogic.servlet.internal.ServletRequestImpl.execute(ServletRequestImpl.java


:2039)
        at weblogic.kernel.ExecuteThread.execute(ExecuteThread.java:139)
        at weblogic.kernel.ExecuteThread.run(ExecuteThread.java:120)
  Thanks again ,
-Cyrus

-----Original Message-----
From: thomas.cherel@ascentialsoftware.com
[mailto:thomas.cherel@ascentialsoftware.com]
Sent: Wednesday, June 12, 2002 5:35 PM
To: axis-user@xml.apache.org
Subject: RE: Exposing EJBs as web services...

------_=_NextPart_001_01C213AF.D7A36750--