Nothing specifically related to Android: more a java question while
struggling making the switch from objective c to java:
1. In Java static methods when implemented in derived classes are
hidden, not overridden. If I have a method foo() in class A and B.
Execution of: A b = new B(); b.foo() will execute method foo() in
class A. That causes me a problem because if I use factory methods in
classes, for each subclass I need to reimplement the static factory
method. I was wondering how people solved this with or without
reflection (I am okay paying the performance toll at object creation).
2. I am trying to replicate the easy functionality of the
NSClassFromString method. Basically, if I have a string for a full
qualified class name, what is the best way to invoke a static method
with a known signature for that class.
In objective c:
Class foo()
{
NSString *r = @"Bar";
Class c = NSClassFromString(r);
return c;
}
then you can call method sna() on class Bar with [foo() sna:d]
So far in Java using reflection, I came up with this convoluted code
that doesn't replicate the behavior for the parameters for the
function (I pass back the object reference, not the method back,
therefore I also have to pass the parameter to call the method):
static SuperClassOfBar foo(float d) {
try {
String r = "Bar";
Class c = Class.forName("com.example."+r); // Fully
qualified name for class
Class partypes[] = new Class[1];
partypes[0] = Float.TYPE;
Method m = c.getDeclaredMethod("sna", partypes);
Object arglist[] = new Object[1];
arglist[0] = d;
Object o = m.invoke(null, arglist);
return SuperClassOfBar.class.cast(o);
} catch (Exception e) {
return null;
}
It works but it's heavy and not pretty. I understand that leaving a
dynamic language like objective c , I have to make some compromises,
but I may miss something about Java for not having found something
more lightweight for such a generic programming functionality. Any
suggestions to simplify this implementation are welcome.
Thanks in advance.
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