metaprogramming in java

* ASM 
  library to generate bytecode

* Tabpestry 
  uses metaprogramming 

* Plastic
  sort of higher level library thatn ASM for "metaprogramming"   

* Extending Methods 
** MethodAdvice
   Advise method to manage transaction commit
   With advise
   Declare class with interface PlasticClass, can make plastic method

* With Transformations
  somewhat bluring the line between compliation and runtime

* Layers of Concerns
  like logging, etc, 
  can chain advice

* Implement New Methods on the fly
  eg you can add a method to get a hashcode for an object to the class 
  (this could also be done with reflection... but that incures runtime penalty among other things)

* Instantiating
  can't just use new, because you'd get the non-plastified version of the class
** instantiation framework
   Class.forName("com.ex.something").getConstructor().getInstance 

* Testing with Spock
  basically, test the behavior not , eg, what methods are invoked ala mocks

* "API != Interface"
  API more like a contract
  plastic allows you to bind a contract to your classes


* random 
  programming "Essence"

* callbacks
  happen against one instance of the conduit , for all instances of the plastic object
  to work around, you generate a conduite per object 

* Trinity
** Bytecode manipulation
** Annotations
** Component Architecture


* examples
  https://github.com/hlship/plastic-demos
  https://howardlweisship.com