Re: Service Class as Singleton Class

[Aaron Knauf]

Thanks, Glen,

I hunted for something like that at the time, in docs and in the source 
code.  I obviously didn't hunt hard enough, though.

ADK

Glen Daniels wrote:

Hi Aaron, Niket:

We did think of this too. :)  Allow me to refer you to:

http://ws.apache.org/axis/faq.html#faq8

If you simply set scope="application" on your service, Axis will only create a single instance of the service class.

--Glen

 

-----Original Message-----
From: Aaron Knauf [mailto:[EMAIL PROTECTED]
Sent: Tuesday, May 27, 2003 12:36 AM
To: [EMAIL PROTECTED]
Subject: Re: Service Class as Singleton Class
The problem is that Axis instantiates and new service class instance 
each time the service is invoked, using reflection to find the public 
constructor.  It would be difficult to get Axis to cater for 
singletons, 
as the getInstance method could be called anything.

I found the instantiation of a new service class for each 
invocation to 
be a problem, so I worked around it by implementing my 
service class as 
a proxy to a singleton implementation class.  The wrapper gets 
instantiated every time, but the class that implements all 
the logic is 
only instantiated once.  This was to avoid expensive 
initialization code 
(such as starting up a pool of connections to a CORBA server) 
from being 
executed repeatedly, but it had the handy side effect of 
allowing me to 
read in my config from the WSDD file in this wrapper, too, 
therby hiding 
the fact that the thing was running as a web service from the 
impl class.

Hope this helps.

Cheers

ADK

Niket Anand wrote:

   



   Hello All,
   I am newbie to Axis. I am facing problem as
   java.lang.InstantiationException
   
     

<file:///C:/jdk1.3.1/docs/api/java/lang/InstantiationException.html>
   

   exception when my service class is Singleton class and having
   private constructor and getInstance() to get instance of this
   class. When axis client ask for a method from the service class
   then it throw this exception. If I remove the Singleton ability
   and provide public constructor then it works fine. But I want it
   to be remain Singleton . Please help me How to work with Service
   class as Singleton and what modification needs to be 
     

done in wsdd.
   

    
   waiting for reply...
   thanks,
   Niket