uk.ac.starlink.votable
Class VOStarTable

java.lang.Object
  uk.ac.starlink.table.AbstractStarTable
      uk.ac.starlink.votable.VOStarTable

All Implemented Interfaces:

StarTable

public class VOStarTable
extends AbstractStarTable

A StarTable implementation based on a VOTable.

Some of the FIELD attributes defined by the VOTable format correspond to standard information in the corresponding ColumnInfo object, and some do not. Those that do are accessed using the relevant ColumnInfo getter/setter methods directly, for instance

     String ucd = table.getColumnInfo(0).getUCD();
 

The ones that don't are stored in the ColumnInfo's auxiliary metadata keyed using the various *_INFO public static variables defined in this class. These are accessed using the ColumnInfo.getAuxDatum(uk.ac.starlink.table.ValueInfo) method, for instance:

     String id = (String) table.getColumnInfo(0)
                                 .getAuxDatumValue(VOStarTable.ID_INFO);
 

In the same way, if you set an auxiliary metadata item under one of these keys, like this:

     DescribedValue idVal = new DescribedValue(VOStarTable.ID_INFO, "COL0");
     table.getColumnInfo(0).setAuxDatum(idVal);
 

then if the result is written to a VOTable the relevant attribute will be attached to the corresponding FIELD element.

Field Summary

static ValueInfo	DATATYPE_INFO ValueInfo for VOTable datatype attribute.
static ValueInfo	ID_INFO ValueInfo for VOTable ID attribute.
static ValueInfo	PRECISION_INFO ValueInfo for VOTable precision attribute.
static ValueInfo	REF_INFO ValueInfo for VOTable ref attribute.
static ValueInfo	TYPE_INFO ValueInfo for VOTable type attribute.
static ValueInfo	UCD_INFO ValueInfo for VOTable ucd attribute.
static ValueInfo	UTYPE_INFO ValueInfo for VOTable utype attribute.
static ValueInfo	WIDTH_INFO ValueInfo for VOTable width attribute.
static ValueInfo	XTYPE_INFO ValueInfo for VOTable xtype attribute.

Constructor Summary

VOStarTable(TableElement votable)
Construct a VOStarTable from a TABLE element.

Method Summary

Object	getCell(long lrow, int icol) The AbstractStarTable implementation of this method throws an UnsupportedOperationException, since unless otherwise provided there is no random access.
List	getColumnAuxDataInfos() Goes through the table columns (ColumnInfo objects) and picks out all the AuxData items which exist, generalising where necessary and returning a union of them in alphabetical order by name.
int	getColumnCount() Returns the number of columns in this table.
ColumnInfo	getColumnInfo(int icol) Returns the object describing the data in a given column.
List	getParameters() Returns a list of table parameters, that is items which pertain to the entire table.
Object[]	getRow(long lrow) The AbstractStarTable implementation of this method constructs a row by repeated invocation of AbstractStarTable.getCell(long, int).
long	getRowCount() Returns the number of rows in this table, if known.
RowSequence	getRowSequence() Returns an object which can iterate over all the rows in the table sequentially.
static ValueInfo	getValueInfo(FieldElement field) Returns a ValueInfo object suitable for holding the values in a VOTable Field (or Param) object.
boolean	isRandom() The AbstractStarTable implementation of this method returns false.

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

checkedLongToInt, getName, getParameterByName, getURL, setName, setParameter, setParameters, setURL

Methods inherited from class java.lang.Object

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

Field Detail

ID_INFO

public static final ValueInfo ID_INFO

ValueInfo for VOTable ID attribute.

UCD_INFO

public static final ValueInfo UCD_INFO

ValueInfo for VOTable ucd attribute.

UTYPE_INFO

public static final ValueInfo UTYPE_INFO

ValueInfo for VOTable utype attribute.

XTYPE_INFO

public static final ValueInfo XTYPE_INFO

ValueInfo for VOTable xtype attribute.

WIDTH_INFO

public static final ValueInfo WIDTH_INFO

ValueInfo for VOTable width attribute.

PRECISION_INFO

public static final ValueInfo PRECISION_INFO

ValueInfo for VOTable precision attribute.

REF_INFO

public static final ValueInfo REF_INFO

ValueInfo for VOTable ref attribute.

TYPE_INFO

public static final ValueInfo TYPE_INFO

ValueInfo for VOTable type attribute.

DATATYPE_INFO

public static final ValueInfo DATATYPE_INFO

ValueInfo for VOTable datatype attribute.

Constructor Detail

VOStarTable

public VOStarTable(TableElement votable)
            throws IOException

Construct a VOStarTable from a TABLE element. The data itself is inferred or constructed from the state and content of the element.

Parameters:

votable - Table VOElement

Throws:

IOException

Method Detail

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

getRowCount

public long getRowCount()

Description copied from interface: StarTable

Returns the number of rows in this table, if known. If the number of rows cannot be (easily) determined, a value of -1 will be returned.

Specified by:

getRowCount in interface StarTable

Specified by:

getRowCount in class AbstractStarTable

Returns:

the number of rows, or -1

isRandom

public boolean isRandom()

Description copied from class: AbstractStarTable

The AbstractStarTable implementation of this method returns false.

Specified by:

isRandom in interface StarTable

Overrides:

isRandom in class AbstractStarTable

Returns:

true if table random access methods are available

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

getParameters

public List getParameters()

Description copied from interface: StarTable

Returns a list of table parameters, that is items which pertain to the entire table. Each element of this list must be a DescribedValue object.

Specified by:

getParameters in interface StarTable

Overrides:

getParameters in class AbstractStarTable

Returns:

a List of DescribedValue objects constituting table-wide metadata not covered elsewhere in this interface

getColumnAuxDataInfos

public List getColumnAuxDataInfos()

Description copied from class: AbstractStarTable

Goes through the table columns (ColumnInfo objects) and picks out all the AuxData items which exist, generalising where necessary and returning a union of them in alphabetical order by name. Subclasses should override this if they can do better, for instance providing an order for the keys.

Specified by:

getColumnAuxDataInfos in interface StarTable

Overrides:

getColumnAuxDataInfos in class AbstractStarTable

Returns:

a list of all the auxiliary metadata ValueInfo items which in fact crop up in column metadata

See Also:

ColumnInfo.getAuxData()

getRowSequence

public RowSequence getRowSequence()
                           throws IOException

Description copied from interface: StarTable

Returns an object which can iterate over all the rows in the table sequentially.

Specified by:

getRowSequence in interface StarTable

Specified by:

getRowSequence in class AbstractStarTable

Returns:

an object providing sequential access to the table data

Throws:

IOException - if there is an error providing access

getRow

public Object[] getRow(long lrow)
                throws IOException

Description copied from class: AbstractStarTable

The AbstractStarTable implementation of this method constructs a row by repeated invocation of AbstractStarTable.getCell(long, int).

Specified by:

getRow in interface StarTable

Overrides:

getRow in class AbstractStarTable

Parameters:

lrow - the index of the row to retrieve

Returns:

an array of the objects in each cell in row irow

Throws:

IOException - if there is an error reading the data

getCell

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

Description copied from class: AbstractStarTable

The AbstractStarTable implementation of this method throws an UnsupportedOperationException, since unless otherwise provided there is no random access.

Specified by:

getCell in interface StarTable

Overrides:

getCell in class AbstractStarTable

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

getValueInfo

public static ValueInfo getValueInfo(FieldElement field)

Returns a ValueInfo object suitable for holding the values in a VOTable Field (or Param) object. The datatype, array shape and other metadata in the returned object are taken from the relevant bits of the supplied field.

Parameters:

field - the FieldElement object for which the ValueInfo is to be constructed

Returns:

a ValueInfo suitable for field