org.jfree.report

Class EmptyReportData

Implemented Interfaces:
DataSet, ReportData

public class EmptyReportData
extends java.lang.Object
implements ReportData

Creation-Date: 22.04.2006, 14:25:04
Author:
Thomas Morgner

Fields inherited from interface org.jfree.report.ReportData

BEFORE_FIRST_ROW

Constructor Summary

EmptyReportData()

Method Summary

void
close()
Closes the datasource.
Object
get(int column)
int
getColumnCount()
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.

Constructor Details

EmptyReportData

public EmptyReportData()

Method Details

close

public void close()
            throws DataSourceException
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

get

public Object get(int column)
            throws DataSourceException
Specified by:
get in interface DataSet

getColumnCount

public int getColumnCount()
            throws DataSourceException
Specified by:
getColumnCount in interface DataSet

getColumnName

public String getColumnName(int column)
            throws DataSourceException
Specified by:
getColumnName in interface DataSet

getCursorPosition

public int getCursorPosition()
            throws DataSourceException
Specified by:
getCursorPosition in interface ReportData

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:

isReadable

public boolean isReadable()
            throws DataSourceException
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.

next

public boolean next()
            throws DataSourceException
This method produces the same result as 'setCursorPosition(getCursorPosition() + 1);'
Specified by:
next in interface ReportData
Returns:

setCursorPosition

public boolean setCursorPosition(int cursor)
            throws DataSourceException
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
Parameters:
cursor -
Returns:
true, if moving the cursor succeeded, false otherwise.