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From "Reinhard Poetz" <>
Subject RE: Introducing IOC for Java classes created in flowscript
Date Thu, 20 Nov 2003 15:51:09 GMT

From: Sylvain Wallez

> Hi all,
> Flowscript currently gives two means to use Java classes: use 
> components 
> (cocoon.getComponent()) or simply create a Java object and 
> use it (new 
> MyClass()). As it's not very convenient to create a new component and 
> install it in cocoon.xconf just to call Java code from the flow, the 
> second solution is often used.

yep, unfortunatly ...

> But a problem comes when these Java objects need to access 
> e.g. request 
> parameters, session attributes, components, etc: the only way 
> is to pass 
> them the "cocoon" object that provides this access.
> But "cocoon" is of class "FOM_Cocoon" which is very specific to the 
> internals of flowscript and linking code to this specific class isn't 
> IMO a good thing to do. Furthermore, accessing elements of the object 
> model through getters isn't consistent with the way it's 
> usually done in 
> other Cocoon code and violates IOC.

yep. when I startet to add interception capabilities to flowscript I had
to copy the existing FOM_Cocoon because it had direct references to the
interpreter (I think this needs some re-thinking ...) Anyway: If we once
have more than one ControlFlow impl (not necessarily in the cocoon-cvs
but maybe outside) this will become a problem!

> So I added a new method to "cocoon" that sets up an object 
> just as if it 
> were an Avalon component by honoring the various lifecycle interfaces.
> Some useful lifecycle interfaces to implement are of course 
> LogEnabled 
> and Serviceable, but also Contextualizable, which gives access to the 
> object model through the ContextHelper class.
> Example:
>   var foo = new Foo();
>   cocoon.setupObject(foo);
>   foo.doIt("blah");
> This way of setting up object respects IOC, avoids using the very 
> specific "FOM_Cocoon" class and gently educates people to the good 
> things provided by Avalon.

I like your solution - big +1 to add it to the FOM!
This also means that this object can used as Avalon components outside
of flowscript, doesn't it?


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