org.dellroad.stuff.string
Class CSVOutput

java.lang.Object
  org.dellroad.stuff.string.CSVOutput

public class CSVOutput
extends Object

CSV file output stream that ensures values are matched to the correct columns. This class requires the OpenCSV library.

See Also:

OpenCSV

Constructor Summary

CSVOutput(CSVWriter writer, Iterable<String> columns)
Constructor.

CSVOutput(Writer writer, Iterable<String> columns)
Constructor.

CSVOutput(Writer writer, String... columns)
Constructor.

Method Summary

void	close() Close this instance and the underlying output.
void	flush() Flush output.
protected String	formatDate(String columnName, Date date) Format a Date value.
protected String	formatObject(String columnName, Object value) Format a CSV column value.
void	writeRow(Map<String,?> row) Output a CSV row.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

CSVOutput

public CSVOutput(Writer writer,
                 String... columns)

Constructor.

Parameters:

writer - destination for the CSV output

columns - CSV columns names in their desired order

Throws:

IllegalArgumentException - if writer is null

IllegalArgumentException - if columns is null

IllegalArgumentException - if columns contains a duplicate column name

CSVOutput

public CSVOutput(Writer writer,
                 Iterable<String> columns)

Constructor.

Parameters:

writer - destination for the CSV output

columns - CSV columns names, iterated in their desired order

Throws:

IllegalArgumentException - if writer is null

IllegalArgumentException - if columns is null

IllegalArgumentException - if columns contains a duplicate column name

CSVOutput

public CSVOutput(CSVWriter writer,
                 Iterable<String> columns)

Constructor.

Parameters:

writer - CSV output object

columns - CSV columns names, iterated in their desired order

Throws:

IllegalArgumentException - if writer is null

IllegalArgumentException - if columns is null

IllegalArgumentException - if columns contains a duplicate column name

Method Detail

writeRow

public void writeRow(Map<String,?> row)

Output a CSV row.

Parameters:

row - mapping from column name to value; missing or values are treated as null

Throws:

IllegalArgumentException - if row contains an unknown column name

flush

public void flush()
           throws IOException

Flush output.

Throws:

IOException

close

public void close()
           throws IOException

Close this instance and the underlying output.

Throws:

IOException

formatObject

protected String formatObject(String columnName,
                              Object value)

Format a CSV column value.

The implementation in CSVOutput applies the following logic:

• null values are output as the empty string
• Boolean values are output as 1 or 0
• Date values are output by delegating to formatDate()
• All other objects are output using String.valueOf(java.lang.Object)

Subclasses should override as needed.

Parameters:

columnName - name of the column

value - column value; will be null if no value was present in the Map parameter to writeRow(java.util.Map)

formatDate

protected String formatDate(String columnName,
                            Date date)

Format a Date value.

The implementation in CSVOutput delegates to DateEncoder.encode().

Subclasses should override as needed.

Parameters:

columnName - name of the column

date - column value

Throws:

IllegalArgumentException - if date is null