org.jfree.report

Class EmptyReportData

java.lang.Object

org.jfree.report.EmptyReportData

All Implemented Interfaces:

DataSet, ReportData

public class EmptyReportData
extends java.lang.Object
implements ReportData

Creation-Date: 22.04.2006, 14:25:04

Author:

Thomas Morgner

Field Summary

Fields inherited from interface org.jfree.report.ReportData

BEFORE_FIRST_ROW

Constructor Summary

Constructors

Constructor and Description
EmptyReportData()

Method Summary

Modifier and Type	Method and Description
void	close() Closes the datasource.
java.lang.Object	get(int column)
int	getColumnCount()
java.lang.String	getColumnName(int column)
int	getCursorPosition()
boolean	isAdvanceable() This operation checks, whether a call to next will be likely to succeed.
boolean	isReadable() Checks, whether this report-data instance is currently readable.
boolean	next() This method produces the same result as 'setCursorPosition(getCursorPosition() + 1);'
boolean	setCursorPosition(int cursor) Moves the cursor back to an already visited position.

Methods inherited from class java.lang.Object

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

Constructor Detail

EmptyReportData

public EmptyReportData()

Method Detail

getCursorPosition

public int getCursorPosition()
                      throws DataSourceException

Specified by:

getCursorPosition in interface ReportData

Throws:

DataSourceException

isReadable

public boolean isReadable()
                   throws DataSourceException

Description copied from interface: ReportData

Checks, whether this report-data instance is currently readable. A report-data instance cannot be readable if it is positioned before the first row. (The look-ahead system of 'isAdvanceable()' will prevent that the datasource is positioned behind the last row.)

Specified by:

isReadable in interface ReportData

Returns:

true, if the datarow is valid, false otherwise.

Throws:

DataSourceException

setCursorPosition

public boolean setCursorPosition(int cursor)
                          throws DataSourceException

Description copied from interface: ReportData

Moves the cursor back to an already visited position. Calling this method for an row number that has not yet been read using 'next' is undefined, whether that call succeeds is implementation dependent. Calls to position zero (aka BEFORE_FIRST_ROW) will always succeeed (unless there is a physical error, which invalidated the whole report-data object).

Specified by:

setCursorPosition in interface ReportData

Returns:

true, if moving the cursor succeeded, false otherwise.

Throws:

DataSourceException

isAdvanceable

public boolean isAdvanceable()
                      throws DataSourceException

This operation checks, whether a call to next will be likely to succeed. If there is a next data row, this should return true.

Specified by:

isAdvanceable in interface ReportData

Returns:

Throws:

DataSourceException

next

public boolean next()
             throws DataSourceException

Description copied from interface: ReportData

This method produces the same result as 'setCursorPosition(getCursorPosition() + 1);'

Specified by:

next in interface ReportData

Returns:

Throws:

DataSourceException

close

public void close()
           throws DataSourceException

Description copied from interface: ReportData

Closes the datasource. This should be called at the end of each report processing run. Whether this closes the underlying data-source backend depends on the ReportDataFactory. Calling 'close()' on the ReportDataFactory *must* close all report data objects.

Specified by:

close in interface ReportData

Throws:

DataSourceException

getColumnCount

public int getColumnCount()
                   throws DataSourceException

Specified by:

getColumnCount in interface DataSet

Throws:

DataSourceException

getColumnName

public java.lang.String getColumnName(int column)
                               throws DataSourceException

Specified by:

getColumnName in interface DataSet

Throws:

DataSourceException

get

public java.lang.Object get(int column)
                     throws DataSourceException

Specified by:

get in interface DataSet

Throws:

DataSourceException