RE: [wsdm] [mows] WS endpoint definition

Title: Message

Here 
is a shortened definition of an endpoint

 

"An 
endpoint is an addressable location at which a Web Service can be 
accessed according to the associated binding of a 
specified interface. One Web Service can have multiple 
endpoints. In simple terms it is a network location identified by a URI 
which accepts XML requests to a service. XML requests must be formed according 
to WSDL description.

 

In 
OGSI, a Grid Service has endpoints and a Grid Service Instance has endpoints. 
Both can be described in WSDL."

 

 

-- Igor 
Sedukhin .. () 
-- (631) 342-4325 .. 1 CA Plaza, 
Islandia, NY 11788 

  

  
-----Original Message-----
From: Sedukhin, Igor S 
  
Sent: Thursday, August 07, 2003 9:13 PM
To: 
  
Subject: [wsdm] [mows] WS endpoint 
  definition

  
Fulfilling my AI from last MOWS 
  call. 

  
I propose that we stick to the 
  definition given in WSDL 1.2 draft. In my opinion it is quite 
  precise. 

  
WSDL describes Web services 
  starting with the messages that are exchanged between the service 
  provider and requester. The messages themselves are described abstractly and 
  then bound to a concrete network protocol and message format. A message 
  consists of a collection of typed data items. An exchange of messages between 
  the service provider and requester is described as an 
  operation.

  
A collection of operations is 
  called an interface. An interface is bound to a concrete protocol and 
  message format via one or more bindings. A 
  binding, and therefore an interface, is accessible via one or more 
  endpoint, 
  each endpoint having its own URI. A service is a 
  collection of endpoints bound to the same interface.

  
Again, in simple terms it is a 
  "place" identified with a URI where XML (or SOAP if some prefer) requests 
  could be sent. 

  
In case of OGSI, GridServices are 
  WSs that could be described with plain WSDL (via flattening) and therefore 
  accessible via endpoints as well. In case the "factory" approach is used to 
  create "instances" of GridServices, each "instance" is essentially a service 
  (even if it is temporary). The "instance" service has one or more endpoints 
  where the requests could be sent. Therefore, each GridService "instance" 
  endpoint is a WSDL endpoint. Such WSDL can be dynamically generated if so 
  necessary, in fact, it appears inline in a Grid Service Reference. Now, these 
  are my own practical conclusions on this, correct me if I'm wrong. So, (1) 
  GridService has endpoints (2) GridServiceInstance has endpoints 
  too.

  
I have seen the following text in 
  the OGSI Primer which made me somewhat confused on the GridService itself. 
  Technically, I'm pretty sure in the above stated, but logically there could 
  have been some other intentions.

  
In OGSI-terms, a Grid Service is 
  a general term referring to a template, a contract, an 
interface described in GWSDL and the Grid 
  Service Instances that must adhere to it. The 
term Grid Service does not characterise a 
  component that can be part of a Grid 
application (i.e., it does not refer to a software 
  component that can execute operations). 
Instead, it is Grid Service Instances that 
  are the logical recipients of operations. 
In the OGSI world, a Grid Service Instance 
  (GSI) has to be explicitly created (by a 
factory or by the hosting environment) and 
  then registered with a handle resolver. 

  
-- Igor Sedukhin 
  .. () 
-- (631) 342-4325 .. 1 CA Plaza, 
  Islandia, NY 11788