Know the class that invoked a method

Hi!
Is there a way to know which class called a method?
For example, if I have a method in an object: toString(), can I know which object called me?
rzvika2Asked:
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heyhey_Commented:
my example from the PAQ

(some time ago, I have created special utility class for this purpose but I can't find it on my workstation right now)

*****

public class test
{
public static void main(String args[])
{
 demo obj = new demo();

 obj.doIt();
 demo1.staticDoIt();
}
}

class demo1
{
     public static void staticDoIt()
     {
           b bObject = new b();
           bObject.doIt();
     }
}
class demo
{
   
public void doIt()
{
 b bObject = new b();
 bObject.doIt();
}
}

class b
{
public void doIt()
{
try {
throw new Exception();
} catch (Exception e)
{
     ByteArrayOutputStream bos = new ByteArrayOutputStream();
     PrintStream ps = new PrintStream (bos);
     e.printStackTrace(ps);
     ps.close();
     String st = new String (bos.toByteArray());
     st = st.substring(st.indexOf("at") + 3);
     st = st.substring(st.indexOf("at") + 3);
     int n = st.indexOf(".");
     String objName = st.substring(0, n);
     st = st.substring(n + 1);
     n = st.indexOf("(");
     String methodName = st.substring(0, n);
   
     System.out.println("b.doIt() was called from object of class (class) " + objName + ", method " + methodName);
}

}
}
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BaneBaneCommented:
This is messy but you could probably extract the information from the stacktrace.

Hope this helps.
0
 
girionisCommented:
 As BaneBane suggested you can do it by processing the call stack printed to a stream by the printStackTrace() method.

  For a complete example with source code take a look here:

http://developer.java.sun.com/developer/qow/archive/104/

  Hope it helps.

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seguretCommented:
If you have the JDK 1.4, you don't have to use all those parsers anymore : look at the StackTraceElement classe !

All what you have to do is to call  Throwable.getStackTrace(). It returns an array of StackTraceElement. On those elements, you can call the getClassName method.
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xxMariusxxCommented:
new Throwable().printStackTrace();
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doronbCommented:
Hello,


You could try and use some Java reflection and the following code:
_________________________________
import java.lang.reflect.*;

// Class and other code declarations

// Static method to find out which class called our method..
     private static Method sysGetCallerClass;

     static {
          try {
               sysGetCallerClass = System.class.getDeclaredMethod("getCallerClass", null);
               sysGetCallerClass.setAccessible(true);          } catch (Exception ex) {
               ex.printStackTrace();
          }
     }

// More class and code declarations

// Then in any method you want to know the calling class use:
          Class callingClass = null;
          try {
               callingClass = (Class)sysGetCallerClass.invoke(null, null);
          } catch (Exception ex) {
          }
// WARNING: COPY THE ABOVE CODE TO EVERY METHOD THAT NEEDS TO KNOW THE CALLING CLASS, THIS CODE CANNOT BE IN ITS OWN METHOD SINCE IT WILL REPORT ITS OWN CLASS AS CALLING ITSELF.

// NOTE: This code makes use of an un-documented method in the class java.lang.System, this method might one day completely disappear so using this code might be rendered useless in the future.

Hope this helps

Doron
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