What is a Java Proxy class and where do you use it?

Can someone tell me what a Java Proxy Class does and where you use it? How do you use it when you have a non-standard wsdl file, one that wasn't auto-generated?
yankeebushsoftwareAsked:
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ADSLMarkCommented:
That is just a stub to communicate with the outside world. It can be automatically generated from your WSDL. You can use wsdl2java for that.
If that fails, you can always write the code yourself, or let wsdl2java generate some part of it and add your own later on.

Here is an example on wsdl2java:
http://ws.apache.org/axis/java/user-guide.html#WSDL2JavaBuildingStubsSkeletonsAndDataTypesFromWSDL

Mark
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Mayank SAssociate Director - Product EngineeringCommented:
>> do you use it when you have a non-standard wsdl file, one that wasn't auto-generated?

For a non standard WSDL, it means it would be proprietary.

A proxy (in any programming language) basically implements the Proxy design pattern. You use it to call an object you don't have access to directly, and you access it like a local object but it results in calls to the remote object and handles the complications for you - like connecting, passing parameters, serialization/ de-serialization etc:

http://en.wikipedia.org/wiki/Proxy_pattern
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ksivananthCommented:
you can think of the proxy instance of the internet proxy server - where in all the nodes request the proxy server for the internet requests. In java, all the calls are made the proxy instance and the proxy instance knows how to server the request.

For e.g., you have an interface may be thing of a stub,

interface myinterface{
  void method1( int a, int b ) ;

  void method2( String a, String b ) ;

//more method follows,
................
................
................
}

but the implementation reside on some other system, how you will make call to the system?

1. one way of doing the old fashion - text notation...
2. use the proxy pattern

class myinvocationhandler extends InvocationHandler{
    public Object invoke( Object proxy, Method method, Object[] args ) throws Throwable{
         // all the myinterface interface calls are forwarded here using reflection...
         //your implementation to request the server here
    }
}

//here is how you make call to the myservice interface

myinterface service = return Proxy.newProxyInstance( myinterface.class.getClassLoader(), new Class[]{ myinterface.class }, new myinvocationhandler() ) ;

service.method1( 0, 2 ) ;
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Mayank SAssociate Director - Product EngineeringCommented:
Might've been a split....
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