uk.ac.starlink.table

Class ColumnStarTable

java.lang.Object

uk.ac.starlink.table.AbstractStarTable

uk.ac.starlink.table.RandomStarTable

uk.ac.starlink.table.ColumnStarTable

All Implemented Interfaces:

Closeable, AutoCloseable, StarTable

Direct Known Subclasses:

LoopStarTable, RegistryStarTable

public abstract class ColumnStarTable
extends RandomStarTable

A random-access StarTable that manages its data in columns. The data in each column is managed by a ColumnData object which can be accessed directly using the getColumnData(int) method. Columns can be added and substituted. If the columns permit it then table cells can be written to as well as read from.

Concrete subclasses of this abstract class must implement getRowCount(). If you just need a ColumnStarTable with a fixed number of rows you can use the static convenience method makeTableWithRows(long).

Author:

Mark Taylor (Starlink)

Field Summary

Fields

Modifier and Type	Field and Description
List<ColumnData>	columns_

Constructor Summary

Constructors

Constructor and Description
ColumnStarTable() Default constructor.
ColumnStarTable(StarTable template) Initialises a ColumnStarTable using a template StarTable to provide per-table metadata.

Method Summary

Modifier and Type	Method and Description
void	addColumn(ColumnData coldata) Appends a new column to the end of this model.
Object	getCell(long lrow, int icol) Implementations of this method must be safe for concurrent calls from multiple threads.
int	getColumnCount() Returns the number of columns in this table.
ColumnData	getColumnData(int icol) Returns the ColumnData object for a given column.
ColumnInfo	getColumnInfo(int icol) Returns the object describing the data in a given column.
abstract long	getRowCount() Gets the number of rows in the table (which must be applicable to all the columns).
static ColumnStarTable	makeTableWithRows(long nrow) Convenience method to return a ColumnStarTable with a fixed number of rows.
void	setCell(long lrow, int icol, Object value) Stores an object in a given cell of the table.
void	setColumn(int icol, ColumnData coldata) Substitutes a new column for the one which is currently in a given position.

Methods inherited from class uk.ac.starlink.table.RandomStarTable

getRowAccess, getRowSequence, isRandom

Methods inherited from class uk.ac.starlink.table.AbstractStarTable

checkedLongToInt, close, getColumnAuxDataInfos, getName, getParameters, getRow, getRowSplittable, getURL, setName, setParameters, setURL

Methods inherited from class java.lang.Object

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

Methods inherited from interface uk.ac.starlink.table.StarTable

getParameterByName, setParameter

Field Detail

columns_

public List<ColumnData> columns_

Constructor Detail

ColumnStarTable

public ColumnStarTable()

Default constructor.

ColumnStarTable

public ColumnStarTable(StarTable template)

Initialises a ColumnStarTable using a template StarTable to provide per-table metadata. The newly constructed object will have copies of the template's name, parameters etc.

Parameters:

template - the template StarTable

Method Detail

getRowCount

public abstract long getRowCount()

Gets the number of rows in the table (which must be applicable to all the columns). Since this is a RandomStarTable the return value must be non-negative.

Specified by:

getRowCount in interface StarTable

Specified by:

getRowCount in class RandomStarTable

Returns:

number of rows

getColumnCount

public int getColumnCount()

Description copied from interface: StarTable

Returns the number of columns in this table.

Specified by:

getColumnCount in interface StarTable

Specified by:

getColumnCount in class AbstractStarTable

Returns:

the number of columns

getColumnInfo

public ColumnInfo getColumnInfo(int icol)

Description copied from interface: StarTable

Returns the object describing the data in a given column.

Specified by:

getColumnInfo in interface StarTable

Specified by:

getColumnInfo in class AbstractStarTable

Parameters:

icol - the column for which header information is required

Returns:

a ValueInfo object for column icol

getCell

public Object getCell(long lrow,
                      int icol)
               throws IOException

Description copied from class: RandomStarTable

Implementations of this method must be safe for concurrent calls from multiple threads.

Specified by:

getCell in interface StarTable

Specified by:

getCell in class RandomStarTable

Parameters:

lrow - the index of the cell's row

icol - the index of the cell's column

Returns:

the contents of this cell

Throws:

IOException - if there is an error reading the data

setCell

public void setCell(long lrow,
                    int icol,
                    Object value)
             throws IOException

Stores an object in a given cell of the table.

Parameters:

lrow - the row index

icol - the column index

value - the value to store

Throws:

IOException - if an I/O error occurs

UnsupportedOperationException - if column icol is not writable (!getColumnData(icol).isWritable());

getColumnData

public ColumnData getColumnData(int icol)

Returns the ColumnData object for a given column.

Parameters:

icol - the index of the column for which the result is required

Returns:

the ColumnData for column icol

addColumn

public void addColumn(ColumnData coldata)

Appends a new column to the end of this model.

Parameters:

coldata - the new column object to add

setColumn

public void setColumn(int icol,
                      ColumnData coldata)

Substitutes a new column for the one which is currently in a given position. The old one is discarded.

Parameters:

icol - the column index to change

coldata - the new column data object

makeTableWithRows

public static ColumnStarTable makeTableWithRows(long nrow)

Convenience method to return a ColumnStarTable with a fixed number of rows.

Parameters:

nrow - the number of rows this table will have