Say I have this code that uses some input (e.g. a URL path) to determine which method to run, via reflection:
// init
map.put("/users/*", "viewUser");
map.put("/users", "userIndex");
// later
String methodName = map.get(path);
Method m = Handler.class.getMethod(methodName, ...);
m.invoke(handler, ...);
This uses reflection so the performance can be improved. It could be done like this:
// init
map.put("/users/*", new Runnable() { public void run() { handler.viewUser(); } });
map.put("/users", new Runnable() { public void run() { handler.userIndex(); } });
// later
Runnable action = map.get(path);
action.run();
But manually creating all those Runnables like that has its own issues.
I'm wondering, can I generate them at runtime? So I'd have an input map as in the first example, and would dynamically create the map of the second example.
Sure, generating it is just a matter of building a string, but what about compiling and loading it?
Note: I know the performance increase is so little it's a perfect example of premature optimization. This is therefore an academic question, I'm interested in runtime generation and compilation of code.