MobiLink Synchronization User's Guide
  Writing Synchronization Scripts in Java
    Writing Java synchronization logic

User-defined start classes

You can define start classes that are loaded automatically when the server is started. The purpose of this feature is to allow you to write Java code that executes at the time the MobiLink server starts the JVM—before the first synchronization. This means you can create connections or cache data before a user synchronization request.

You do this with the DMLStartClasses option of the dbmlsrv9 -sl java option. For example, the following is part of a dbmlsrv9 command line. It causes mycl1 and mycl2 to be loaded as start classes.

-sl java(-DMLStartClasses=com.test.mycl1,com.test.mycl2)

Classes are loaded in the order in which they are listed. If the same class is listed more than once, more than one instance is created.

All start classes must be public and must have a public constructor that either accepts no arguments or accepts one argument of type ianywhere.ml.script.ServerContext.

The names of loaded start classes are output to the MobiLink log with the message "Loaded JAVA start class: classname".

For more information about Java virtual machine options, see -sl java option.

To see the start classes that are constructed at server start time, see getStartClassInstances.

Example 

Following is a template start class. It starts a daemon thread that processes events and creates a database connection. (Not all start classes will need to create a thread but if a thread is spawned it should be a daemon thread.)

import ianywhere.ml.script.*;
import java.sql.*;

public class StartTemplate extends
   Thread implements ShutdownListener {
//=================================================
  ServerContext   _sc;
  Connection      _conn;
  boolean         _exit_loop;

  public StartTemplate( ServerContext sc )
  //=============================================
                        throws SQLException
  {
    // perform setup first so that an exception will
    // cause MobiLink startup to fail
 _sc       = sc;
    // create a connection for use later
    _conn      = _sc.makeConnection();
    _exit_loop = false;
    setDaemon( true );
    start();
  }

  public void run()
  //===============
  {
    _sc.addShutdownListener( this );
    // we can't throw any exceptions through run()
    try {
       handlerLoop();
       _conn.close();
       _conn = null;
    } catch( Exception e ) {
       // print some error output to the MobiLink log
       e.printStackTrace();
       // we will die so we don't need to be notified
       // of shutdown
       _sc.removeShutdownListener( this );
       // ask server to shutdown so that this fatal
       // error will be fixed
       _sc.shutdown();
    }
    // shortly after return this thread will no longer
    // exist
    return;
  }

 public void shutdownPerformed( ServerContext sc )
  //===============================================
  // stop our event handler loop
  {
    try {
       // wait max 10 seconds for thread to die
  join( 10*1000);
    } catch( Exception e ) {
       // print some error output to the MobiLink log
       e.printStackTrace();
   }
  }

  private void handlerLoop()
  //================throws InterruptedException
  {
      while( !_exit_loop ) {
        // Handle events in this loop. Sleep not
        // needed, we should block on event queue.
        sleep( 1*1000 );
    }
  }
}