On Wed, 2004-04-14 at 09:59, Niclas Hedhman wrote:
On Wednesday 14 April 2004 15:40, Carsten Ziegeler wrote:
This key should be a simple string, so the above could read: locator.locate(Football.class, "red");
Forgive me for a naive question;
What is the difference of the above, from;
servicemanager.lookup( "red-football" ); or servicemanager.lookup( "/footballs/red" );
Or in the case you need someone else to figure it out;
FootballLocator fbl = (FootballLocator) sm.lookup( "footballs" ); Football ball = fbl.locate( "red" );
and the
public class MyOrdinaryComponent implements FootballLocator
{
private ServiceManager sm;
public Football locate( String color ) { if( color.equals( "red" ) ) return (Football) sm.lookup( "red-ball" ); if( color.equals( "blue" ) ) return (Football) sm.lookup( "blue-ball" ); if( color.equals( "green" ) ) return (Football) sm.lookup( "green-ball" ); return (Football) sm.lookup( "gray-ball" ); } }
Is what you wrote above something that works today in Merlin? I thought the argument supplied to sm.lookup is the name of a dependency, and that you can only be dependent on one implementation of Football?
The above code is a little incomplete - here is a full version:
public class MyOrdinaryComponent
implements FootballLocator
{
private ServiceManager sm; /**
* @avalon.dependency type=Football" key="red-ball";
* @avalon.dependency type=Football" key="blue-ball";
* @avalon.dependency type=Football" key="green-ball";
*/
public MyOrdinaryComponent( ServiceManager manager )
{
sm = manager;
} public Football locate( String color )
{
if( color.equals( "red" ) )
return (Football) sm.lookup( "red-ball" );
if( color.equals( "blue" ) )
return (Football) sm.lookup( "blue-ball" );
if( color.equals( "green" ) )
return (Football) sm.lookup( "green-ball" );
return (Football) sm.lookup( "gray-ball" );
}
}Given the above merlin will happly associate instances of Football against the respective lookup keys. On the container side you can setup directives that control which components get assigned to respective keys.
For example:
<container name="demo">
<component name="red-football" class="StandardFootball">
<configuration>red-color</configuration>
</component> <component name="blue-football" class="StandardFootball">
<configuration>blue-color</configuration>
</component> <component name="green-football" class="StandardFootball">
<configuration>green-color</configuration>
</component> <component name="football-thing" class="MyOrdinaryComponent">
<dependencies>
<dependency key="red-ball" source="red-football"/>
<dependency key="blue-ball" source="blue-football"/>
<dependency key="green-ball" source="green-football"/>
</dependencies>
</component></container>
Alternatively - if MyOrdinaryComponent had a dependency on a finder facility, it could do this automatically based on matching features (providing we expose selection semantics in the model and update finder to enable this sort of query functionality).
Cheers, Stephen.
--
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