Package uk.ac.starlink.table
Class CountCheckRowSequence
java.lang.Object
uk.ac.starlink.table.CountCheckRowSequence
- All Implemented Interfaces:
Closeable
,AutoCloseable
,RowData
,RowSequence
,uk.ac.starlink.util.Sequence
RowSequence wrapper class that guarantees a given number of rows.
The expectation is that the underlying row sequence has the declared
row count, but if it has a different number the output of this sequence
is forced to the declared value by adding dummy rows or discarding
extra rows as required. If such adjustments are required, suitable
messages are written through the logging system.
- Since:
- 10 Nov 2022
- Author:
- Mark Taylor
-
Method Summary
Modifier and TypeMethodDescriptionvoid
close()
Indicates that this sequence will not be required any more.getCell
(int icol) Returns the contents of a cell in the current row.Object[]
getRow()
Returns the contents of the current table row, as an array with the same number of elements as there are columns in this table.static RowSequence
getSafeRowSequence
(RowSequence rseq, int ncol, long nrow) Returns a row sequence guaranteed to give the required number of rows.boolean
next()
Attempts to advance the current row to the next one.
-
Method Details
-
next
Description copied from interface:RowSequence
Attempts to advance the current row to the next one. Iftrue
is returned the attempt has been successful, and iffalse
is returned there are no more rows in this sequence. Since the initial position of a RowSequence is before the first row, this method must be called before current row data can be accessed using theRowSequence.getCell(int)
orRowSequence.getRow()
methods.- Specified by:
next
in interfaceRowSequence
- Specified by:
next
in interfaceuk.ac.starlink.util.Sequence
- Returns:
true
iff this sequence has been advanced to the next row- Throws:
IOException
- if there is some error
-
getCell
Description copied from interface:RowSequence
Returns the contents of a cell in the current row. The class of the returned object should be the same as, or a subclass of, the class returned bygetColumnInfo(icol).getContentClass()
. An unchecked exception will be thrown if there is no current row (next
has not yet been called).- Specified by:
getCell
in interfaceRowData
- Specified by:
getCell
in interfaceRowSequence
- Parameters:
icol
- column index- Returns:
- the contents of cell
icol
in the current row - Throws:
IOException
- if there is an error reading the data
-
getRow
Description copied from interface:RowSequence
Returns the contents of the current table row, as an array with the same number of elements as there are columns in this table. An unchecked exception will be thrown if there is no current row (next
has not yet been called).- Specified by:
getRow
in interfaceRowData
- Specified by:
getRow
in interfaceRowSequence
- Returns:
- an array of the objects in each cell in row
irow
- Throws:
IOException
- if there is an error reading the data
-
close
Description copied from interface:RowSequence
Indicates that this sequence will not be required any more. This should release resources associated with this object. The effect of calling any of the other methods following aclose
is undefined.- Specified by:
close
in interfaceAutoCloseable
- Specified by:
close
in interfaceCloseable
- Specified by:
close
in interfaceRowSequence
- Throws:
IOException
-
getSafeRowSequence
Returns a row sequence guaranteed to give the required number of rows.- Parameters:
rseq
- row sequence on which the returned one is basedncol
- number of columns (required for constructing dummy rows)nrow
- required number of rows, or -1 for no requirement- Returns:
- safe row sequence; if
nrow<0
the input sequence will be returned
-