Archive for the ‘Windows’ Category

Alfresco document preview doesn’t work for MS Office files (.doc, .docx, .ppt .pptx etc) although it works for pdf files. I get “This document can’t be previewed.” message.

For reasons which are not obvious for me the installation and starting of alfrescoOpenOffice service doesn’t
always work properly during automated Alfresco install/start script execution. If you have the same problem
here is the solution for windows environment.
1. Start – > run  – > services.msc Check if alfrescoOpenOffice service is listed. If not go to {alfresco install dir}\openoffice\scriptsand execute “openoffice_serviceinstall INSTALL” with administrative privileges.

2. Every time after starting alfresco by {alfresco install dir}\servicerun START execute also{alfresco install dir}\openoffice\scripts\openoffice_servicerun START.

3. If you’re not happy with auto starting openoffice service with Windows change alfrescoOpenOffice execution
type to “Manual”.

4. MS Office documents preview in Alfresco should be working just fine now :)

Tomcat uses wrong path although CATALINA_HOME and CATALINA_BASE have correct values.

The cause of the problem may be that your web application uses tomcat6.exe instead of catalina.bat to start up.  From my observations it seems tomcat6.exe as opposed to catalina.bat uses environment variables only for the 1st run to copy CATALINA_HOME and CATALINA_BASE values to Windows Registry. Thereafter these parameters start to live on their own;) I had one instance of Tomcat for my Openbravo developer stack and the other for Alfresco. Tomcat6.exe used old values regardless of completly separate instalation of Alfresco dev stack.
You can edit these and other variables directly via Windows Registry editor, the path is:

HKLM/SOFTWARE/Apache Software Foundation/…..

or more conveniently you can use tomcat6w.exe GUI:

tomcat6w //ES//<serviceName> (eg. tomcat6w //ES//alfrescoTomcat)

calls a neat window where you can edit variables you need to run your web app properly.

there’s also //MS// parameter which will call a simple application monitoring given service:

tomcat6w //MS//<serviceName>

If you want to read more about running Tomcat as Windows service with tomcat6.exe go to an article from Apache Tomcat documentation.

Hope this helps someone:)

How to call/invoke external DLL library method/function from Java code?

Introduction

Java’s JVM allows you to do many smart things but sometimes you may be forced to directly use external library or writing code in pure java would be very time-consuming comparing it with something more low-leveled. I stumbled upon such a problem and had to use a .dll driver from a hardware provider. Of course I googled it and didn’t find much info, and what I’ve found  mostly concerned about JNI (Java Native Interface). I would like to tell you about JNA which is fast and simple to use in aforementioned task.

So, how does it work? The only thing you have to do is to download and import JNA (Java Native Access) to your project and write a simple class.
Hereunder you can analyse a simple Java program which uses a sample .dll. You can download my java code and .dll library sources later.

Java code:

package jnahelloworldtest;

import com.sun.jna.Library;
import com.sun.jna.Native;
import com.sun.jna.NativeLong;
import com.sun.jna.Platform;
import com.sun.jna.*;

/** Simple example of native library declaration and usage. */
public class Main {
    public interface simpleDLL extends Library {
        simpleDLL INSTANCE = (simpleDLL) Native.loadLibrary(
            (Platform.isWindows() ? "simpleDLL" : "simpleDLLLinuxPort"), simpleDLL.class);
		// it's possible to check the platform on which program runs, for example purposes we assume that there's a linux port of the library (it's not attached to the downloadable project)
        byte giveVoidPtrGetChar(Pointer param); // char giveVoidPtrGetChar(void* param);
        int giveVoidPtrGetInt(Pointer param);   //int giveVoidPtrGetInt(void* param);
        int giveIntGetInt(int a);               // int giveIntGetInt(int a);
        void simpleCall();                      // void simpleCall();
    }

    public static void main(String[] args) {

        simpleDLL sdll = simpleDLL.INSTANCE;

        sdll.simpleCall();  // call of void function

        int a = 3;
        int result1 = sdll.giveIntGetInt(a);  // calling function with int parameter&result
        System.out.println("giveIntGetInt("+a+"): " + result1);

        String testStr = "ToBeOrNotToBe";
        Memory mTest = new Memory(testStr.length()+1);  // '+1' remember about extra byte for \0 character!
        mTest.setString(0, testStr);
        String testReturn = mTest.getString(0); // you can see that String got properly stored in Memory object
        System.out.println("String in Memory:"+testReturn);

        Memory intMem = new Memory(4);  // allocating space
        intMem.setInt(0, 666); // setting allocated memory to an integer
        Pointer intPointer = intMem.getPointer(0);

        int int1 = sdll.giveVoidPtrGetInt(Pointer.NULL); // passing null, getting default result
        System.out.println("giveVoidPtrGetInt(null):" + int1); // passing int stored in Memory object, getting it back
        int int2 = sdll.giveVoidPtrGetInt(intMem);
       //int int2 = sdll.giveVoidPtrGetInt(intPointer);  causes JVM crash, use memory object directly!
        System.out.println("giveVoidPtrGetInt(666):" + int2);

        byte char1 = sdll.giveVoidPtrGetChar(Pointer.NULL);  // passing null, getting default result
        byte char2 = sdll.giveVoidPtrGetChar(mTest);        // passing string stored in Memory object, getting first letter

        System.out.println("giveVoidPtrGetChar(null):" + (char)char1);
        System.out.println("giveVoidPtrGetChar('ToBeOrNotToBe'):" + (char)char2);

    }
}

Mappings table

Not every native type maps directly to Java type, furthermore a class representing pointers had to be introduced.  You can read a handy type mapping table below:

Native Type Size Java Language Type Common Windows Types
char 8-bit integer byte BYTE, TCHAR
short 16-bit short short WORD
wchar_t 16/32-bit character char WCHAR, TCHAR
int 32-bit integer int DWORD
int boolean value boolean BOOL
long 32/64-bit integer NativeLong LONG
long long, __int64 64-bit integer long
float 32-bit FP float
double 64-bit FP double
char* C string String LPTCSTR
void* pointer Pointer LPVOID, HANDLE, LPXXX

Downloads:

  • DLLVisual Studio source project – ready to use Visual Studio 2010 project. You can alter it to continue experimenting with invoking DLL methods of library attached to the Netbeans project.
  • Netbeans project – ready to use NetBeans 6 project using example code explained in this article with appropriate jars and DLL library attached
  • JNA library jars – link to official JNA libraries download page

Useful links:

DLL library C++ functions source :

#include "simpleDLL.h"

#include <stdexcept>

using namespace std;

namespace simpleDLLNS
{
    char simpleDLL::giveVoidPtrGetChar(void* param)
    {
        if(param != 0)
		{
		char* paramChrPtr = (char*)param;
		return *paramChrPtr;
		}
		else
		{
			return 'x';
		}

    }

	int simpleDLL::giveIntGetInt(int a)
	{
		return 2*a;
	}

	void simpleDLL::simpleCall(void)
	{
		int x = 3;
		return;
	}

	int simpleDLL::giveVoidPtrGetInt(void* param)
	{
		if(param!=0)
		{
			int* x = (int*)param;
			return *x;

		}
		else
		{
			return -1;
		}
	}

}

How to properly run java console application with a doubleclick (Windows)

You’ve developed a java application which runs fine in your IDE but now you want to show your application to the outer world. Running a java program by setting up windows command window and then typing java -jar myProgram.jar paramA paramB .. may be a bit confusing for an everyday user, so the simplier means to do it are quite desirable.

A simple way to achieve this is to use a batch (.bat) file.

Let’s assume you have a console java application which takes one parameter – a configuration filepath and name. You can create a simple script file which will run this application in console for you after a doubleclick.

You should:

1. Create a text file like this :

@echo off
 set jarpath="JavaApp.jar"
 java -jar %jarpath% %CD%\Config.txt
 PAUSE

%CD% is a pseudo-variable which holds the working directory. It’s useful when you eg. want to load a config file located in the same folder as your .bat file.
PAUSE displays a localized version of “Press any key to continue…” message.

2. Save it as .bat file.
3. The program is ready for double click run!