java - How to administrate Strategy Pattern behaviors at runtime? -


i'm reading head first design patterns book when doubt came head.

in first chapter, studying strategy pattern taught make interchangeable classes. according picture below:

strategy pattern

my question: if want make desktop application visual interface , let users have more privileges others administrate ducks , behaviors? so, example create flyrocketpowered behavior @ runtime. how can achieve this?

i mean, these behaviors weird me represented classes, because can't see how make them editable @ user level, every time flybehavior, quackbehavior or duck subclass needs created/deleted/changed users have ask me modify source code creating/deleting/changing classes, not want, need more developer-independent.

edit

say want make screen add fly behavior (just add, not edit, not remove), there have 2 fields, first behavior name, second content printed when fly() method called.

by editing source code creating class this:

public class flyrocketpowered implements flybehavior {    public void fly() {       system.out.println("i’m fl ying rocket!");    } }

what need make @ user level?

firstly i'd love book. it's favourite programming book.

to question: think missunderstood strategy pattern little bit ;) goal not enable users create new behaviors @ runtime. pattern, can give 'admins' panel give duck available behavior. behaviors still generated @ compiletime. can interchange behaviors @ runtime

additionally, funfact: totally possible let 'admin' create new behaviors @ runtime. take @ java compiler api. if think doing so, remember how big security hole , how unimaginable stupid worst case customer is.


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