Using JNA to get/set application identifier

Question

Following up on my previous question concerning the Windows 7 taskbar, I would like to diagnose why Windows isn\'t acknowledging that my application is independent of

Answer 1

If you just need to set the AppUserModelId then the above JNA code is enough. However if you want to take advantage of the new Windows 7 features in you Java application then check out J7Goodies a Java library providing Windows 7 taskbar extensions.

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EDIT: more info from J7Goodies Programmer's Guide

4.2. Setting AppUserModelID

In order to use any of the Windows 7 features an application must explicitly set its process identifier – Application User Model ID (AppUserModelID). It can have no more than 128 characters and cannot contain spaces. Each section should be camel-cased, for example:

 CompanyName.ProductName.SubProduct.VersionInformation

This identifier must be set before any GUI (window) is shown. You set it by calling:

// Remember to set AppUserModelID before creating any UI
AppUserModelId.setCurrentProcessId("StrixCode.J7Goodies.Appname");

4.3. Setting Window Properties

A Java application cannot be pinned to the Windows 7 taskbar unless its window properties are defined. The properties consist of four fields:

• AppUserModelID – the same as passed to AppUserModelId.setCurrentProcessId(String)
• RelaunchDisplayName – application’s name
• RelaunchCommand – the full command used to launch the application. In case of a Java program it will be: <path to javaw.exe> -jar <path to application jar>
• RelaunchIcon – path to application’s icon

Important: RelaunchCommand and RelaunchDisplayName must always be set together. To set these properties use the straightforward WindowProperties class.

WindowProperties props = new WindowProperties(myFrame);
props.setRelaunchCommand("<full path to javaw.exe –arguments>");
props.setRelaunchDisplayName("My Java Application");
props.setRelaunchIcon("<full path to an .ico or .exe file>");
props.setAppUserModelID("StrixCode.J7Goodies.Appname");
props.save();

Answer 2

I didn't see your question before otherwise I would have given a try even without a bounty.

Here is what I came up with. Please note, as stated in the code itself, I didn't implement proper memory clean up with the CoTaskMemFree function (from Ole32.dll). So I suggest you take only the implementation for SetCurrentProcessExplicitAppUserModelID()

package com.stackoverflow.AppIdTest;

import com.sun.jna.Native;
import com.sun.jna.NativeLong;
import com.sun.jna.Pointer;
import com.sun.jna.WString;
import com.sun.jna.ptr.PointerByReference;

public class AppIdTest
{

  public static void main(String[] args) throws Exception
  {
    setCurrentProcessExplicitAppUserModelID(AppIdTest.class.getName());

    System.out.println(getCurrentProcessExplicitAppUserModelID());
  }

  // DO NOT DO THIS, IT'S JUST FOR TESTING PURPOSE AS I'M NOT FREEING THE MEMORY
  // AS REQUESTED BY THE DOCUMENTATION:
  //
  // http://msdn.microsoft.com/en-us/library/dd378419%28VS.85%29.aspx
  //
  // "The caller is responsible for freeing this string with CoTaskMemFree when
  // it is no longer needed"
  public static String getCurrentProcessExplicitAppUserModelID()
  {
    final PointerByReference r = new PointerByReference();

    if (GetCurrentProcessExplicitAppUserModelID(r).longValue() == 0)
    {
      final Pointer p = r.getValue();


      return p.getString(0, true); // here we leak native memory by lazyness
    }      
    return "N/A";
  }

  public static void setCurrentProcessExplicitAppUserModelID(final String appID)
  {
    if (SetCurrentProcessExplicitAppUserModelID(new WString(appID)).longValue() != 0)
      throw new RuntimeException("unable to set current process explicit AppUserModelID to: " + appID);
  }

  private static native NativeLong GetCurrentProcessExplicitAppUserModelID(PointerByReference appID);
  private static native NativeLong SetCurrentProcessExplicitAppUserModelID(WString appID);


  static
  {
    Native.register("shell32");
  }
}

Does it work for you?

At least here it correctly prints back:

com.stackoverflow.AppIdTest.AppIdTest

Answer 3

Here's a more simple example on how to call SetCurrentProcessExplicitAppUserModelID via JNA:

import com.sun.jna.*;
import com.sun.jna.win32.*;

interface Shell32 extends StdCallLibrary {

    Shell32 INSTANCE = (Shell32) Native.loadLibrary("shell32", Shell32.class, W32APIOptions.DEFAULT_OPTIONS);

    NativeLong SetCurrentProcessExplicitAppUserModelID(WString appID);

}