Accessing method of one application from another

[Barry Andrews]

Hi All,
This may seem strange, but I want to know if it is possible to access a method in one class from another totally separate application. If I understand correctly, I need to have the instance of the class to use the Method.invoke() call. So, is there a way to get the instance of another class of some application that is already running? Also, I have been doing some experimenting with the reflect API and I do not quite understand what the Class[] is that must be passed to getMethod(String name, Class[] parameterTypes) of the Class class. The docs say it is the formal parameters of the method you want to get. Could someone please explain how this is used to represent the formal parameters? I get a NoSuchMethodException when I run this sample code, I think because "params" is not defined correctly. Anyone that can help me on this matter is greatly appreciated!!
Thanks,
Barry

import com.level8.appbuilder.gui.HpsInternalTable;
import java.lang.reflect.*;
public class WinRunGetInfo extends ClassLoader
{
   public WinRunGetInfo()
   {
      }
   public String getTableContent(int col, int row)
   {
      Class myClass = null;
      Method meth   = null;
      try
      {
         myClass = Class.forName("com.level8.appbuilder.gui.HpsInternalTable");
         System.out.println(myClass.toString());
          }
      catch(ClassNotFoundException ce)
      {
         ce.printStackTrace();
         }
      Integer param1 = new Integer("0");
      Integer param2 = new Integer("0");
      Class[] params = new Class[] {myClass};
      Object[] args = new Object[] {param1,param2};
      try
      {
         meth = myClass.getMethod("getValueAt",params);
         }
      catch(NoSuchMethodException ne)
      {
         ne.printStackTrace();
         }
      try
      {
         meth.invoke(null,args);
         }
      catch(IllegalAccessException ie)
      {
         ie.printStackTrace();
         }
      catch(InvocationTargetException it)
      {
         it.printStackTrace();
         }
      return null;
      }//end getTableContent() method
   public static void main(String[] args)
   {
      WinRunGetInfo wi = new WinRunGetInfo();
      wi.getTableContent(10,10);
      }
   }

[Patricia Fulk]

Hi Barry,
I had the same problem and I have figured it out. Here is the example I did and it works now. Hope this helps.
Trish
---------------------------------------------------------------
import javax.servlet.http.*;
import javax.servlet.*;
import java.util.*;
import java.io.*;
import java.lang.reflect.Method;
public class test1 extends HttpServlet {
private static final String CONTENT_TYPE = "text/html";
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
performTask(request,response);
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
performTask(request,response);
}

public void performTask(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException{
PrintWriter out = null;
response.setContentType(CONTENT_TYPE);
out = response.getWriter();
out.println("test");
String a = "help";
try {
Class classObj = Class.forName("test1");
Class[] params = new Class[3];
params[0] = Integer.TYPE;
params[1] = a.getClass();
params[2] = out.getClass();
Method method = classObj.getMethod("testMethod",params);
test1 obj2 = new test1();
Object[] args = new Object[3];
args[0] = new Integer(10);
args[1] = a;
args[2] = out;
Object retObj = method.invoke(obj2,args);
} catch (Exception e) {
out.println(e);
}
out.println("performTask:here ");
}
public void testMethod(int i, String a, PrintWriter out) {
out.println(a);
out.println(i);
}
}

[Barry Andrews]

Great! Thanks for the help!

[Kyle Brown]

You know, this IS what RMI and other distributed object technologies are for...
Don't reinvent the wheel!
Kyle
------------------
Kyle Brown,
Author of Enterprise Java (tm) Programming with IBM Websphere
See my homepage at http://members.aol.com/kgb1001001 for other WebSphere information.