I’ve been trying out the DROOLS-TEMPLATES project, really impressed so far, surprised there isn’t more buzz about this project.   I wrote a new version of the DataProviderCompiler that takes a SQL ResultSet instead of a org.drools.template.DataProvider.    I don’t think it will be useful to that many people, so I’m not going to try and add it to the code base, but I’ll provide it here.  I used it for testing out templates, but for our actual production code, I will naturally be using Hibernate to retrieve the rules from the DB (so I can take advantage of Hibernate cache.)  It is much quicker to set up a template test with this compiler though.    It also allows you to put the data in whatever types you like in the database, as long as you add a String converter for that type in processData(), like:   <pre>                     case java.sql.Types.DOUBLE:                         cell = String.valueOf(rs.getInt(cellNum));                         break; </pre>   Calling Code (based on drools-examples\drools-examples-drl\src\main\java\org\drools\examples\DataDrivenTemplateExample.java)   <pre>     ResultSet rs;     try {         Statement sta = conn.createStatement();         rs = sta.executeQuery("SELECT * FROM RulePricingPolicy");       // TODO: you need to catch or handle     } catch (SQLException e) {     }       final ResultSetCompiler converter = new ResultSetCompiler();     final String drl = converter.compile(rs, getTemplate()); </pre>   Here is the ResultSet Compiler:   <pre> import org.drools.template.parser.TemplateContainer; import org.drools.template.parser.DefaultTemplateContainer; import org.drools.template.parser.TemplateDataListener; import org.drools.template.parser.DataListener;   import java.io.InputStream; import java.util.List; import java.util.ArrayList; import java.sql.ResultSet; import java.sql.ResultSetMetaData; import java.sql.SQLException;   /**  * <p> A Drools template compiler which takes a ResultSet and compiles it into  * a template using DefaultTemplateContainer.  * </p>  *  * @author bxt, Aug 19, 2009 1:53:38 PM  *         <br>  *         Copyright © 2008 Customized Services Administrators, Inc.  *         All Rights Reserved.  */ public class ResultSetCompiler {   /**  * Generates DRL from a data provider for the spreadsheet data and templates.  *  * @param rs       the resultset for the table data  * @param template the string containing the template resource name  * @return the generated DRL text as a String  */ public String compile(final ResultSet rs,                       final String template) {     final InputStream templateStream = this.getClass().getResourceAsStream(template);     return compile(rs,             templateStream); }   /**  * Generates DRL from a data provider for the spreadsheet data and templates.  *  * @param rs             the resultset for the table data  * @param templateStream the InputStream for reading the templates  * @return the generated DRL text as a String  */ public String compile(final ResultSet rs,                       final InputStream templateStream) {     TemplateContainer tc = new DefaultTemplateContainer(templateStream);     closeStream(templateStream);     return compile(rs,             new TemplateDataListener(tc)); }   /**  * Generates DRL from a data provider for the spreadsheet data and templates.  *  * @param rs       the resultset for the table data  * @param listener a template data listener  * @return the generated DRL text as a String  */ public String compile(final ResultSet rs,                       final TemplateDataListener listener) {     List<DataListener> listeners = new ArrayList<DataListener>();     listeners.add(listener);     processData(rs,             listeners);     return listener.renderDRL(); }   /**  * Iterate through the resultset.  * @param rs       the resultset for the table data  * @param listeners list of template data listener  */ private void processData(final ResultSet rs,                          List<DataListener> listeners) {       try {         ResultSetMetaData rsmd = rs.getMetaData();         int colCount = rsmd.getColumnCount();           int i = 0;           while (rs.next()) {             newRow(listeners, i, colCount);             for (int cellNum = 1; cellNum < colCount + 1; cellNum++) {                 String cell;                   int sqlType = rsmd.getColumnType(cellNum);                 switch (sqlType) {                     case java.sql.Types.DATE:                         cell = rs.getDate(cellNum).toString();                         break;                     case java.sql.Types.INTEGER:                     case java.sql.Types.DOUBLE:                         cell = String.valueOf(rs.getInt(cellNum));                         break;                     default:                         cell = rs.getString(cellNum);                 }                   newCell(listeners,                         i,                         cellNum -1,                         cell,                         DataListener.NON_MERGED);             }             i++;         }           //TODO: you need to throw or handle     } catch (SQLException e) {     }       finishData(listeners); }   private void finishData(List<DataListener> listeners) {     for (DataListener listener : listeners) {         listener.finishSheet();     } }   private void newRow(List<DataListener> listeners,                     int row,                     int cols) {     for (DataListener listener : listeners) {         listener.newRow(row,                 cols);     } }   public void newCell(List<DataListener> listeners,                     int row,                     int column,                     String value,                     int mergedColStart) {     for (DataListener listener : listeners) {         listener.newCell(row,                 column,                 value,                 mergedColStart);     } }   protected void closeStream(final InputStream stream) {     try {         stream.close();     } catch (final Exception e) {         System.err.print("WARNING: Wasn't able to correctly close stream for rule template. " + e.getMessage());     } } } </pre>