Re: [RT] Component Persistence

[Stephen McConnell]

Alexis Agahi wrote:

On Sunday 02 November 2003 14:05, Stephen McConnell wrote:

<snip/>

 

Mapping from MyStateValueType (an interface) to a home is not the same
as service to provider resolution. Instead, what you want to locate is a
component that implements a home interface for the MyStateValueType -
e.g. MyStateValueTypeHome is the home interface and
MyStateValueTypeHomeProvider is the component implementation that
provides creation, retrival and destruction of instance of
MyStateValueType.
At the meta-data level would would need something like:

 <component class="MyDemoComponent" name="whatever">
   <identity>
     <key>12345</key>
   </identity>
 </component>
The container on creation of an identifiable component resolves the home
factory (an implicit lifecycle dependency) and if the meta-data declares
a key, then a persistent value is retrieved and supplied to the
component via a context entry.  If no identity is supplied, a new state
value is created and supplied.
Any thoughts?
   



I'm not sure to understand clearly your approach.
Tell me if I'm wrong
You suggest 3 parts
1/ compenent: implementing home interface (2)
2/ home: interface that define persisted data
3/ provider: impl that provides custom finder for home interface of the 
component (1)

Close.

but I dont get clearly identity/home purpose. 

I'll explain below.

Should home define method that 
will be used by provider to establish persitence? (if yes, then this sounds 
nice ,))

Here is a move detailed breakdown of the terms I'm using:

 * identifiable component - an instance of a identifiable component type
 * identifiable component type - a type that includes an <indentifiable>
      elements declaring a home interface
 * home - a component implementing a home interface
 * home interface - defintion of storage value creation, query
      and destruction operations
 * home component - a component that implements the home interface
      and handles storage value creation query and destruction
      using some persistence solution
So for example, lets imagine we have something called a User and that
we maintain multiple users.  From this we would need:
Interfaces:

 * User - an service interface
 * UserStorage - an interface defining operation on a user storage
     value instance
 * UserHome - the home interface
Classes:

 * DefaultUser - an identifiable component
 * DefaultUserStorage - a class implementing UserStorage using a
     particular persistence solution
 * DefaultUserHome - implementation of the UserHome
A container on deploying a identifiable component would locate and
deploy a component implementing the UserHome service, get an instance of
UserStorage from the home and add this to the identifiable
components context.
Cheers, Steve.

--

Stephen J. McConnell
mailto:[EMAIL PROTECTED]


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