runtime evolution

Run-Time Evolution through Explicit Meta-Objects

Jorge Ressia, Lukas Renggli, Tudor Gîrba, Oscar Nierstrasz

Tuesday, October 5, 2010

To enable change at run-time, a system must be self-aware and be able to fully reflect on itself.


To enable change at run-time, a system must be self-aware and be able to fully reflect on itself.

Instrospection


Query

Intercession


Modify

Structural Reflection


ClassesObjectsMethods

InstructionsInstance Variables


That is not enough


Dynamic Representation


We need to reflect on the dynamic representation of a program, that is, the operational execution.This is called Behavioral Reflection pioneered by Smith in the context of Lisp

Behavioral Reflection


Behavioral reflection provides a way to intercept and change the execution of a program. It is concerned with execution events, i.e., method execution, message sends, or variable assignments.

Behavioral Reflection

Smith1982


Behavioral reflection provides a way to intercept and change the execution of a program. It is concerned with execution events, i.e., method execution, message sends, or variable assignments.

Message SendMessage ReceiveMethod LookupObject Creation

State Read/Write


CodAMcAffer 1995


Is that all?


It is not possible to foresee all potential reification that might be required at runtime.

What if we need a new reification?


It is not possible to foresee all potential reification that might be required at runtime.

To enab le run t ime change we must reify Meta-objects explicitely

Thesis


Albedo


Structural Meta-objects

Behavioral Meta-objects

Albedo


Structural Meta-Object


add methodremove method

add stateremove state


Object

Class


- Removing accessors.

Object

Meta-object

Class


- Removing accessors.

BehavioralMeta-Object


message sendmessage received

state writestate read

object creation


Object

Class


Method Look up

Object

Meta-object

Class


Method Look up

Object

Meta-object

Class

Object

M


Method Look up

Composables


Object Object


Object Object

Meta-object


Object Object

Meta-object

Meta-object


Object ObjectMeta-object

Meta-object

Meta-object


Reusable


Object

ObjectObject

Meta-objects


Object

Object

ObjectObject

Meta-objects


Object

Object

ObjectObject

Object

Meta-objects


Extensible


Partial Behavioral Reflection



ReflexTanter 2003



ReflexTanter 2003

Reflectivity

Denker 2008


AST


Examples?

Conclusions


- runtime- flexible- object oriented- dynamic- a Model that we can reflect upon.

Albedohttp://scg.unibe.ch/research/Albedo


http://scg.unibe.ch/research/Albedo

http://scg.unibe.ch/research/Albedo

runtime evolution

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