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From "Deepal Jayasinghe" <>
Subject Re: More on the processor/mediator divide
Date Fri, 06 Jan 2006 10:24:38 GMT
Hi paul;

+1 for the approach , I added some comment have a look at those

~Future is Open~

  ----- Original Message ----- 
  From: Paul Fremantle 
  Sent: Friday, January 06, 2006 4:12 PM
  Subject: More on the processor/mediator divide


  Yesterday on the chat I gave a quick overview of the idea of removing the processor/mediator
divide. I don't take credit for this idea. Ant suggested it - I think it was on a previous
chat. Anyway, at the time I didn't like it much. But since then it has slowly wormed its way
into my head. 

  Here is a better description (I hope).

  The idea is that for any given message, it goes to a single instance of a class that implements
the mediator interface. This "master mediator" is typically a "tree" node - in other words
it has references to other mediators which it executes. 

  How does the tree of mediators get built? 

  Well the standard way is this: There is an interface xml.MediatorFactory. This takes the
XML, parses it and creates a Mediator instance. The xml is just the same as today. The MediatorFactory
is pretty much the new name for the existing ProcessConfigurator interface. 

  I think its better rather than creating instance for each invocation , cant we create Mediators
at the initiation time and reuse them , I think mediators are state less , if they want to
keep some status they will do them via some kind of context.

  Of course another way of creating a tree of mediators is to new up different kinds of mediators
and then "wire" them together using Java calls. Or someone could write a different kind of

  So the basic runtime structure is almost the same as today. The user can use <mediator>
tags to use their own mediators (API). The extension writer can create a new MediatorFactory
and Mediator to create a new extension - which then appears in the XML file as a new tag.
The only difference is that the design is simpler, cleaner, lighter. And then the decision
about processor/mediator is gone. 

  The only other change is that we need to make sure the SynapseEnvironment is always available.
So to keep the mediator interface simple, we could add a method onto the SynapseMessage interface
  SynapseMessage.getSynapseEnvironment (). This also means we can ditch the EnvironmentAware
interface so we also make the API simpler too.

  Please take time to think this through... and feel free to ask me questions if I haven't
explained it clearly. 

  Whatever we decide - this won't upset the M1 plan.


  Paul Fremantle
  VP/Technology, WSO2 and OASIS WS-RX TC Co-chair

  "Oxygenating the Web Service Platform",

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