> -----Original Message----- > From: Harvinder Singh [mailto:[EMAIL PROTECTED] > Sent: 25 October 2004 17:02 > To: Avalon framework users > Subject: RE: Error while running embedded merlin > > Hi Niclas, > > I tried the below mentioned steps but was not successful. > > Actually my requirement is as follows : > I was using Avalon components as of now and am planning to move over to > Merlin. > In the earlier scenario, the component definition was an xml file having > an > attribute "type". > This type was used to differentiate between 2 components (A and B) having > the same implementation > i.e. in my implementation, I used to check for the "type" and based on > that > performed diff operations. > Actually, I had the control over deployment of components and thus was > able > to read the component definition and make a configuration object > for the type,etc for each component and put in some object. In my > implementation, I used to get the type from this particular > object and check it to perform various operations.(Please note that there > were two component definitions > A.xml and B.xml. A.xml had type as 'A' and B.xml had type as 'B') > > Now in Merlin, the component definitions became transformed into .xinfos > and the components were defined in the block.xml
In merlin (and Metro) the information about a 'type' of component is contained in the .xinfo. Information about the deployment of one or more instances of that type is contained in the block descriptor. > But now, my component implementation does not know about the type > attribute which earlier it used to. If you have a component implementation that needs information about the type of another component they you can use the composition api. This provides information about the component types and all associated deployment scenarios plus the ability to add new deployment scenarios at runtime. > Actually, Merlin deploys all the components by itself and now I do not > have the liberty to read the xinfo of > each component and make the configuration object which can then be used to > make my custom object. There is an example of this in both the merlin and metro svn repositories - it's the dynamics tutorial (planet/tutorials/dynamics). The example demonstrates a component that locates other components, plays around with the configuration info and demonstrates deployment under different scenarios. > Then this can be used by the implementation in > order to proceed further. Is there > any way I can read the xinfos and come up > with a configuration object for each component. There are several possibilities - the most dynamic of which is manipulation of the system via the composition api. > I am doing all this stuff since I do not want to change the component > implmentation at all. > > Please give me some pointers so that I can proceed further without > changing the implmentation for the components. Get yourself signed up to the DPML list - checkout and build metro - then start playing with the dynamics tutorial. Cheers, Steve. > Regards, > Harvinder > > > -----Original Message----- > From: Niclas Hedhman [mailto:[EMAIL PROTECTED] > Sent: Thursday, October 21, 2004 1:02 AM > To: Avalon framework users > Subject: Re: Error while running embedded merlin > > > On Thursday 21 October 2004 05:36, Harvinder Singh wrote: > > > Question : Does this mean then that "MyComponent" will get resolved only > if > > it has the same class name as the xinfo file name. > > Infact I tried with a sample component having the classname different > from > > the xinfo file name, and it did not get reolved and gave me an error. > Issue > > here is what suppose if I want to use the same implementation for two > > different components.( my components have very similar functionality and > > thus I wud like to use the same implementation passing a flag each time > > which component to use.) > > I will define both the components in block.xml having the same class > names > > and also an attribute 'type' which would suggest which one to use. > > But the way merlin is behaving, it will need 2 different classes and two > > different xinfos. > > Will something like this work in Merlin : > > > > MyComponent1.xinfo and MyComponent.class - resolves 1st component > > MyComponent2.xinfo and MyComponent.class - resolves 2nd component > > The .xinfo file defines the Type of the component. It does not > define/declare > an instance of the component. > > > If not then please let me know how to achieve that? > > MyComponent.class and MyComponent.xinfo belong together. > Unless MyComponent is from a 3rdParty source, I strongly urge you to let > Magic > produce the .xinfo file automatically. > > In your block, you declare the component's usage, and for singleton > lifestyle > that directly translates to a component instance. > (Please note, that under the Avalon concepts, more than one singleton > instance > of the same class can exist.) > > <block name="MyBlock" > > <classloader> > : > </classloader> > <component name="somename" class="com.me.MyComponent" /> > <component name="anothername" class="com.me.MyComponent" /> > </block> > > If you have other components that are depending on those and it is > important > which instance (for instance different config) is used, you need manual > dependency resolution; > http://avalon.apache.org/central/about/tutorials/basic/dependencies/manu al > .h > tml > > (Also, I urge you to let Magic produce the block file, so that the > classloader > is properly established.) > > > I hope this is enough for you to proceed. > > Cheers > Niclas > -- > +------//-------------------+ > / http://www.bali.ac / > / http://niclas.hedhman.org / > +------//-------------------+ > > > --------------------------------------------------------------------- > To unsubscribe, e-mail: [EMAIL PROTECTED] > For additional commands, e-mail: [EMAIL PROTECTED] > > > --------------------------------------------------------------------- > To unsubscribe, e-mail: [EMAIL PROTECTED] > For additional commands, e-mail: [EMAIL PROTECTED] --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
