UltraLite User's Guide
  Tutorial: Build an Application Using Java

Lesson 5: Add synchronization to your application

Once you have tested that your program is functioning properly, you can remove the lines of code that manually insert data into the ULProduct table. Replace these statements with a call to the JdbcConnection.synchronize() function to synchronize the remote database with the consolidated database. This process will fill the tables with data and you can subsequently execute a select query.

Adding synchronization actually simplifies the code. Your initial version of Sample.java uses the following lines to insert data into your UltraLite database.

PreparedStatement pstmt1 = conn.prepareStatement( ADD_PRODUCT_1 );
   pstmt1.setInt(1, 1);
   pstmt1.setInt(2, 400);
   pstmt1.setString(3, "4x8 Drywall x100");
   int rows1=pstmt1.executeUpdate();
   pstmt1.setInt(1, 2);
   pstmt1.setInt(2, 3000);
   pstmt1.setString(3, "8' 2x4 Studs x1000");
   int rows2=pstmt1.executeUpdate();

This code is included to provide an initial set of data for your application. In a production application, you would not insert an initial copy of your data from source code, but would carry out a synchronization.

To add synchronization to your application

1. Replace the hard-coded inserts with a synchronization call.

   • Delete the instructions listed above, which insert code.

   • Add the following line in their place:

     UlSynchOptions synch_opts = new UlSynchOptions();
     synch_opts.setUserName( "50" );
     synch_opts.setPassword( "pwd50" );
     synch_opts.setScriptVersion( "custdb" );
     synch_opts.setStream( new UlSocketStream() );
     synch_opts.setStreamParms( "host=localhost" );
     ( (JdbcConnection)conn ).synchronize( synch_opts );

     The ULSocketStream argument instructs the application to synchronize over TCP/IP, to a MobiLink synchronization server on the current machine (localhost), using a MobiLink user name of 50.

2. Compile and link your application.

   Enter the following command, with a CLASSPATH that includes the current directory, the UltraLite runtime classes, and the Java runtime classes:

   javac *.java

3. Start the MobiLink synchronization server running against the sample database.

   From a command prompt in your JavaTutorial directory, enter the following command:

   start dbmlsrv9 -c "dsn=UltraLite 9.0 Sample"

4. Run your application.

   From a command prompt in your JavaTutorial directory, enter the following command:

   java Sample

   The application connects, synchronizes to receive data, and writes out information to the command line. The output is as follows:

   Connecting to server:port = localhost(a.b.c.d):2439
   4x8 Drywall x100        Id=1    Price=400
   8' 2x4 Studs x1000      Id=2    Price=3000
   Drywall Screws 10lb     Id=3    Price=40
   Joint Compound 100lb    Id=4    Price=75
   Joint Tape x25x500      Id=5    Price=100
   Putty Knife x25         Id=6    Price=400
   8' 2x10 Supports x 200  Id=7    Price=3000
   400 Grit Sandpaper      Id=8    Price=75
   Screwmaster Drill       Id=9    Price=40
   200 Grit Sandpaper      Id=10   Price=100

In this lesson, you have added synchronization to a simple UltraLite application.

For more information on the JdbcConnection.synchronize() function, see Adding synchronization to your application.