For example, Merlin has something called Dependency Validation.
This means that the container will validate your components
and make sure that all dependencies are satisfied before even starting the components. (ECM and Fortress will just happily start
components and run until one blows up.)
Can we dig into this (its something concrete) - as it raises something that is worrying me. In Merlin a component type declares a bunch of stuff about itself. This includes its dependencies (deployment and runtime), the logging channels it may ask for, perhaps a configuration schema, etc.
* the component author is expecting the container to honor
the criteria expressed by the type * is it reasonable to consider a scenario where a container
that initiates deployment without ensuring a type's constraints
have been fulfilled - I don't believe so * is it reasonable for a container to be configured such that
it's responsibilities are scaled back - I think so - but only
if the container has an overriding responsibility not to
attempt component deployment involving a responsibility it
cannot assureSo getting back to the point of this thread - namely simplification and better profiling of a container. I think that there is room for improvement in the current composition model with respect to a better separation of concerns (mainly focused on the ContainmentModel and ComponentModel and improving the break out concerns such as dependency management). In parallel I sure that the notion of aspects can play a role as well - but I'm not sure where that is just yet.
Stephen.
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