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A report data source is a ordered set of rows. For a report, we assume that the report dataset does not change while the report is processed. Concurrent updates will invalidate the whole precomputed layout. A report dataset will be accessed in a linear fashion. On certain points, the cursor will be reset to the a previously read position, and processing the data will restart from there. It is guaranteed, that the cursor will never be set to a row that is beyond the last row that has been read with 'next()'. If the cursor is out of range, any call to get must return 'null'.
| Field Summary | |
static int |
BEFORE_FIRST_ROW
|
| Method Summary | |
void |
close()
Closes the datasource. |
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 interface org.jfree.report.DataSet |
get, getColumnCount, getColumnName |
| Field Detail |
public static final int BEFORE_FIRST_ROW
| Method Detail |
public int getCursorPosition()
throws DataSourceException
DataSourceException
public boolean setCursorPosition(int cursor)
throws DataSourceException
cursor -
DataSourceException
public boolean isAdvanceable()
throws DataSourceException
DataSourceException
public boolean next()
throws DataSourceException
DataSourceException
public void close()
throws DataSourceException
DataSourceException
public boolean isReadable()
throws DataSourceException
DataSourceException
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