When you say “delegation” do you think of what happens in many design patterns like Decorator - something that can easily be done in plain Java? Or are you thinking of delegation as a language concept like in Self[1]? The latter supports overriding in a full template-and-hook style, the former does not.

Here’s a teaser of my upcoming post then:
OT, AOP and delegation were developed from clearly different starting points, roughly sketched as:
OT: more powerful modules
AOP: better handle crosscutting concerns
Delegation: decompose behavior
It happens that the design issues tackled by these approaches overlap to some (small) extent, but that says nothing about the respective core concepts.

Comparing approaches “in terms of dynamism, coupling and separation of concerns” is a big task. I’ll try to cover that in my post. Certainly all approaches *indend* to by dynamic, support losely coupled designs with excellent separation of concerns. The proof of the pudding is in the eating, but I will give some hints on different priorities among goals.

Actually, dynamism is again a very broad term. Let me just add as an anecdote that at the times of AspectJ 0.6.x I was urging the AspectJ folks to make aspect instances more first-class with better options to programmatically (un)register and/or (de)activate an aspect instance. They decided not to walk that road. While I’d say they lost dynamism, they surely have a different interpretation of dynamism, for which they probably have strong support. Ask them.

Positively speaking: the design of OT/J paid very close attention to what’s already there in Java, be not disruptive, rather strengthen existing concepts than introducing entirely new concepts. Given that we know how to construct an object, the main focus was and is: how do we compose a modular, evolvable system from all those objects? How can this composition be specified in the source code? Flexibly, precisely, succinctly, unambiguously, scalably, ..ly, ..ly…

Once more: thanks for asking.
[1] http://en.wikipedia.org/wiki/Self_(programming_language)

Very interesting concept !

Still, i fail to see the distinction between OT,AOP and delegation.
The three of them are used to separate concerns of a related object.
How would you compare OT to the two other solutions in term of dynamism, coupling and separation of concern ?
Thanks in advance,

Alex

@Chris: With your ultra-short response times I had no problems with any of the bumps. Thanks for all your help! You earned yourself a free seating in an OT-tutorial deluxe

@Florian: long time no see, but here we meet!