Getting (WHND) of windows applications

Question

Hi,
I am trying to develop an application that on windows retrives the handles of a couple of native windows applications, to see if I can remote controll them using the message quea. I am not sure this is the right forum, but the one that seems to match most. I have unsuccesfully tried a couple of other forums.
Does some one know how to retrieve a handle from another application please?
Even without using J/Direct please?
Thanks in advance.
Michael (fairly inexperienced)

Answer 1

Getting the HWND of a Win32 application depends largely on your understanding of the Windows architecture. There are two main approaches from a total-solution perspective. BOTH perspectives rely on Java Native Interface API, but they use it differently. After you decide which of these two options to choose, you need to ask yourself, What input parameters can I provide to determine which Window's HWND I need?
1. Use the JNI, or a third-party library based upon it, to map individual Win32 API calls (like EnumWindows) into a Java class. Then write a Java program that calls these Win32 methods tagged as native in Java. This is the strategy used to implement the Standard Widget Toolkit, by the way...
2. Use the JNI, but in a different way, to call a more complicated Win32 procedure (rather than just the basics of JNI, which allow you to call a DLL which was written in C.) You could use Njawin, for example, to call into a COM DLL (like a Visual Basic application) which itself provides a more complete solution to the problem. APIs like Jawin, JIntegra, Njawin, and JacobGen will take a complicated Win32 binary module (a DLL, TLB, etc. depending upon which solution we're talking about) and interoperate it with Java, allowing you to retrieve Pure Java return types, call methods synchronously or asynchronously, etc.
If you are going to be invoking further native functionality after you get the HWND (as you hinted with the message queue), you will probably want to go with Solution 2; coding directly to the Win32 API is not necessary in many situations. If you need to use JAVA as the front end to your program, but you want a lot of native functionality, then:
1. Write all your native functionality in a high-level, object-oriented, COM-enabled Win32 programming language like Delphi, VB, C++, etc.
2. Code the main native procedure into a public object inside a COM DLL, and use JacobGen or Njawin to be able to call that method from inside Java.