Has anyone done any reflection stuff using java.lang.reflect?  I have been trying some out, but can't get it to work, possibly because of the way Processing wraps the pure Java, and how that might affect scope & names(?)


This was taken & modified from a sun.com example, and throws an error:
Code:

   import java.lang.reflect.*;
	  
  class Foo {
    public float data;
    Foo(){	 data=22.22;     } 
  }	  
   
   
   void setup(){
     size(100,100,P3D);
   }


void draw(){

  noLoop();
  Foo testFoo;//=new Foo();

  try {
    //Class cls = Class.forName("Foo");
    Class cls = Class.forName("testFoo");
    Field fld = cls.getField("data");
    Foo f2obj = new Foo();
	     
    println("data = " + f2obj.data);
    fld.setFloat(f2obj, 12.34);
	    
    println("data = " + f2obj.data);
  }
  catch (Throwable e) {
    System.err.println(e);
  }

}

 

The reason for desiring reflective stuff is I want to be able to set variable values based on their names.  This way I can bind the variable to description, key, midiNote, clamp values, all at once with a custom ParameterControl object.

Hope this makes sense.  Thanks!

@JohnG, I may have missed your point, but that didn't answer the question.

Inner classes can be tricky. The naming of them (I think) is determined by the JDK implementation & memory adresses.

But, there is a solution!

In Processing IDE, the classname of your papplet implementation is just the name of the sketch.

Code:

import java.lang.*;
class Foo{
  
}
void setup(){
  try {
  Class thisApplet = getClass();
Class[] innerClasses = thisApplet.getDeclaredClasses();
System.out.println(Arrays.toString(classes));
  } catch (Exception e){
    e.printStackTrace();
  }
}
 

Worked for me, printed:
[class Temporary_9270_9023$Foo]

Sorry, here's a better example.
(long story short, you want "getSimpleName()")

Code:

import java.lang.reflect.*;

static class Foo{ 
    public static int MY_ID;
    public String toString(){
	   return MY_ID+"";
    }
}

//I realized I don't really understand your purpose, but this SHOULD help.

void setup(){
   Class myC = getClass(); //Returns applet class
   Class[] inner = myC.getDeclaredClasses(); //Contains Foo
   for(Class c : inner){ //java 5.0 syntax, you can change.
	 if(c.getSimpleName().equals("Foo")){ //Not toString()!!!
	     InitializeParams(c);
	     break;
	 }
   }
   System.out.println(Foo.MY_ID);
}
void InitializeParams(Class fooClass){
  try {
  Field data = fooClass.getField("MY_ID");
  data.setInt(null,3);
  } catch (Exception e){
    e.printStackTrace();
  }
}
 

So, this takes static inner classes, and sets the field "MY ID" to 3. the 3 could be read from the applet getParameters that the webpage passes it.

However, the example I realized is ridiculous: if its an inner class, why can't you just set the field? like Foo.field = 3? I'm assuming you have a greater need for this, and I hope I helped.

night.


edit: By the way, there is always this neat little idea.

You have a "Note" object, and it has a pitch field. But you don't really care, much. You just know it has a field NAMED "pitch" and that it holds a float.

So,

public static void setPitch(Object note, float val){
   Class type = note.getClass();
   Field pitch = type.getField("pitch"); //We hope
   pitch.setFloat(note,val);
}

erm... you might have already known that though