The JavaScript interface to the replicator enables filters to be written using standard JavaScript with a complete object-based interface to the internal Java objects and classes that make up the THL data.

For more information on the Rhino JavaScript implementation, see Rhino.

The basic structure of a JavaScript filter is as follows:

// Prepare the filter and setup structures

prepare()
{

}

// Perform the filter process; function is called for each event in the THL

filter(event)
{

// Get the array of DBMSData objects
    data = event.getData();

    // Iterate over the individual DBMSData objects
    for(i=0;i<data.size();i++)
    {
      // Get a single DBMSData object
      d = data.get(i);

      // Process a Statement Event; event type is identified by comparing the object class type

      if (d = instanceof com.continuent.tungsten.replicator.dbms.StatementData)
      {
        // Do statement processing
      }
      else if (d = instanceof com.continuent.tungsten.replicator.dbms.RowChangeData)
      {
        // Get an array of all the row changes
        rows = data.get(i).getRowChanges();

        // Iterate over row changes
        for(j=0;j<rows.size();j++)
        {
          // Get the single row change
          rowchange = rows.get(j);

          // Identify the row change type
          if (rowchange.getAction() == "INSERT")
          {
          }
          ....

      }
    }
  }
}

The following sections will examine the different data structures, functions, and information available when processing these individual events.

logger.info("regexp: Translating string " + valueString.valueOf());

if(col == null)
{
  throw new com.continuent.tungsten.replicator.ReplicatorException(
    "dropcolumn.js: column name in " + schema + "." + table +
    " is undefined - is colnames filter enabled and is it before the dropcolumn filter?"
    );
}