Albert Zhou wrote:
>Steve,
>
>Thanks for your reply. A few more questions for you.
>See below.
>
>--- Stephen McConnell <[EMAIL PROTECTED]> wrote:
>...
>
>
>>If the eventsystem is a component then you would
>>typically declare this
>>as a dependency. It is also feasible to supply a
>>object via the context
>>although this is not recommended practice (using the
>>context constructor
>>arguments in the component profile) -
>>
>>e.g.:
>>
>> <context class="MyContextCLass">
>>
>> <import name="avalon:home" key="base"/>
>> <entry key="location" value="Paris"/>
>> <entry key="special" class="MySpecialClass">
>> <parameter>hello</parameter>
>> </entry>
>> </context>
>>
>>See also:
>>
>>
>>
>>
>http://jakarta.apache.org/avalon/excalibur/merlin/api/
>
>
>> ... merlin/model/ContextDirective.html
>>
>>
>>
>
>1. Who will provide the value of "avalon:home", the
>immediate container, or any enclosing one? Any
>significance of the characters of ':', '.', etc in the
>key, or it's just for readability?
>
The avalon:home is a key to a value provided by the kernel (and therefor
the enclosing containers lifecycle manager).
The colon is a delimiter between the domain and the property name.
>
>2. In the customer container example
>(CustomContainer.xprofile), the context of
>key="merlin:container.manager" is imported. It's
>defined in the DefaultContainer's .xinfo file. How are
>these two are related? Obviously, I missed something
>here.
>
This is Merlin specific key used by a container implememtation to access
the ContainerManager (the enhanced classloader). Normally components
don't need they can access the classloader by getting
Thread.currentThread().getContextClassLoader(), however, during
assembly, a container may be executing within the scope of a parent
thread and so it may need a direct reference to the classloader it has
been assigned. Container iimplementations can use the ContainerManager
instance to do things like dynamic componet addition and so on.
>
>3. How to create and pass a complex value (ie, a
>user-defined object) in the profile? Possible at all?
>
>
1. by creating a component that represents the complex value then
declaring a depedency in the target component
2. by declaring an address (e.g.
corbaloc:iiop:1.2@localhost:2056/planet) in a configuration or
parameters - and the component implemetation handles resolution of an
object from the reference
3. by constructing the object using a context derective (assumming the
complex object can be constructed from constructor originated values -
as per details in last email)
4. privately via some implemetation approach such as accessing a naming
service
>
>
>>>3. How do I configure a non-default component,
>>>preferrably outside the
>>> startup.xml file?
>>>
>>>
>>>
>>You can do this (a) via reference, or (b) via
>>packaging:
>>
>> configuration reference
>> -----------------------
>>
>> <container name=a-container">
>> <component name="my-component"
>>class="MyComponentClass" >
>> <configuration
>>src="../config/bySpecialExternalConfiguration.xml"/>
>> </component>
>> </container>
>>
>>
>>
>
>1. The "resource://" format works, for which the .xml
>file is stored in one of the .jar files.
>
>
Yep.
>2. What else format of the src attribute and where the
>.xml file located, relative to the defining .xml file?
>
>
Regular file names relative to the avalon:home path.
This is currrently the root directory in which Merlin is launched.
>Steve, what I really was asking was this: is there a
>way to "import" a component defined somewhere else or
>defined later that provides a desired service? For
>instance, in my example application, can I import one
>view component in the startup.xml file? Ideally, I
>should be able to import a service provider if it's
>defined and found somewhere otherwise a default one
>will be used.
>
>
Not yet - but its in progress. I have some content here that is
handling the publication however it isn't tied into the assembly
mechanisms at this stage. The objective is to enable containers to
publish services based on disclosure policies at the level of the
component and container. These services will then become candidates for
assembly in other contains and compoents. This included the ability to
export a service access point description between containers enabling
remote assembly, execution and dissasembly across different machines.
>
>
>> packaged configuration
>> ----------------------
>>
>> Just include the configuration as an
>><classname>.xconfig file
>> in the same package as the class.
>>
>>Cheers, Steve.
>>
>>
>>
>
>Thanks once again.
>
>
Its a pleasure.
Cheer, Steve.
>Cheers,
>Albert
>
>=====
>Regards,
>Albert
>
>__________________________________________________
>Do you Yahoo!?
>New DSL Internet Access from SBC & Yahoo!
>http://sbc.yahoo.com
>
>--
>To unsubscribe, e-mail: <mailto:[EMAIL PROTECTED]>
>For additional commands, e-mail: <mailto:[EMAIL PROTECTED]>
>
>
>
>
>
--
Stephen J. McConnell
OSM SARL
digital products for a global economy
mailto:[EMAIL PROTECTED]
http://www.osm.net
--
To unsubscribe, e-mail: <mailto:[EMAIL PROTECTED]>
For additional commands, e-mail: <mailto:[EMAIL PROTECTED]>
