package org.drools.template.jdbc;
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>
*
* To use simply you need a JDBC ResultSet - with the field names mapping to the field names used in the template !
*/
public class ResultSetGenerator {
/**
* 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++;
}
} catch (SQLException e) {
//TODO: you need to throw or handle
}
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());
}
}
}