Using the sample service application

• A section on how to write a Java service is here.
• Source code for a sample java service is here
• Tutorial for using the sample service application.

Writing a service

Writing an NT service in Java follows the same basic rules as writing one with conventional language.

• No Error pop up's. Services run in the background.
• Log Errors to the NT event log. Logging class provides this functionality.
• Services run like Unix Daemon's. They run continuously until asked to stop.
• Main function should loop. If not, the service will run once and end.

Use the properties file extensively, as it is your link to the 'outside world'. Debug modes, log file names, etc. should be included in the file. Changing modes or files would be as easy as stopping the service, editing and saving the properties file and re-starting the service.

To get a basic understanding of what needs to happen, it would be a good idea to visit the HOWTO page now.
Also, see the section on editting the properties file.

The basics of using the Sample Service is as follows:

• Create a new folder for your service.
• Put dsbJavaSvc.jar, jservice.exe, MyAppService.java and service.properties into the new folder.
• Edit the service.properties file to make sure that the paths are set up correctly.
• Edit the service.properties file to ensure that var.service_name is equal to MyAppService.
• Compile the java source file (MyAppService.java): javac MyAppService.java
• Open a command window, change directory to your new folder.
• Install the service: jservice -i MyAppService service.properties
• MyAppService is now a new service. Use the control-panel services function to verify this.
• Start the service via the control panel or via cmd window: net start MyAppService.
• Look in the event log for application entries for your sample application.
• Stop the service via control panel or via net stop MyAppService in the cmd window.

// sample java service application



import java.util.*;

import java.lang.*;

import java.io.*;



Import the dsb.javasvc package, 

remember to set up your classpath correctly to include the .jar file

import dsb.javasvc;



/*

 *   All services should be threads, this allows the StopJavaService class to stop it

 *

 */

public class MyAppService extends Thread

{	

        protected int shutdownPort=0;

        protected int loggingPort=0;



	//declare the stopjavaservice object



	  protected StopJavaService sjs=null;



    	public static void main(String args[]) throws Exception

	{

		new MyAppService();

		

	}

     /* 

      * Start the service application

      *    read in the properties file, especially looking for the shutdown.port property

     */

	public MyAppService()

	{

		Properties p = new Properties( );

		String str;

    		try {

     		 p.load( new FileInputStream( "your_app.properties" ) );

			 
Read in the shutdown port number from your properties file

           	String portname     = p.getProperty( "var.shutdown_port", "0" );

      		shutdownPort = Integer.parseInt(portname);

		// we have the shutdown port now

		   if(shutdownPort > 0)

		   {

			loggingPort = shutdownPort + 1;

			}



	      this.start();

		}

		catch( Exception e)

		{

			// log to stderr

			Logging.LogErr(e.getMessage());

		}

     }

	public void run()

	{

		try {

			sjs = new StopJavaService("StopJavaService");

			// set the listen port (always based upon shutdownPort, it is shutdownPort + 1)

			sjs.setPort(shutdownPort);

		
Set the thread to stop in the StopJavaService class to this

			sjs.setThreadToStop(this);

		
Start the StopJavaService thread.

			sjs.start();

			// do nothing, just waste time

			for(;;)

			{

				this.sleep(20000);

				
Log a message in the event log

				Logging.LogServiceMsg("In the loop",loggingPort);

			}



		}

		catch( Exception e)

		{

			Logging.LogErr(e.getMessage());

		}

		finally {

			Logging.LogErr("Stopping MyAppService...");

				}

      }

	

}