Java Reference
In-Depth Information
To aid us in CSV parsing, we will use Glen Smith's excellent
OpenCsv
library. OpenCsv contains utility classes to ease
the task of working with CSV files. OpenCsv is licensed
under the Apache 2.0 license. It can be downloaded from
http://opencsv.sourceforge.net/
.
Writing a Custom JRDataSource
Implementation
As we have seen from previous examples, all JasperReports datasources
implement the
JRDataSource
interface. JasperReports also includes the
net.
sf.jasperreports.engine.JRRewindableDataSource
interface. This interface
extends
JRDatasource
, adding a single method called
moveFirst()
. The
moveFirst()
method is intended to move the cursor to the first element in the
datasource. Our
CsvDataSource
will implement
JRRewindableDataSource
. Let us
take a look at the source code of the
CsvDataSource
class.
package net.ensode.jasperbook;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.Reader;
import java.util.List;
import net.sf.jasperreports.engine.JRException;
import net.sf.jasperreports.engine.JRField;
import net.sf.jasperreports.engine.JRRewindableDataSource;
import au.com.bytecode.opencsv.CSVReader;
public class CsvDataSource implements JRRewindableDataSource
{
private CSVReader csvReader;
private List rows;
private int currentRowIndex = -1;
private int currentColIndex = 0;
private int totalRows;
public CsvDataSource(Reader reader)
{
try
{
csvReader = new CSVReader(reader);
rows = csvReader.readAll();
totalRows = rows.size();
}
