uk.ac.starlink.table

Class AbstractStarTable

java.lang.Object

uk.ac.starlink.table.AbstractStarTable

All Implemented Interfaces:

java.io.Closeable, java.lang.AutoCloseable, StarTable

Direct Known Subclasses:

AsciiTableStarTable, BintableStarTable, CalcStarTable, CdfStarTable, ColFitsStarTable, EcsvStarTable, FeatherStarTable, GbinStarTable, JDBCStarTable, JoinStarTable, MetadataStarTable, ParquetStarTable, Pds4StarTable, RandomStarTable, SequentialResultSetStarTable, StreamStarTable, VOStarTable

public abstract class AbstractStarTable
extends java.lang.Object
implements StarTable

Abstract base class providing an implementation of the generic and straightforward parts of the StarTable interface. This implementation assumes that random access is not available; subclasses which provide random access should override the isRandom, getCell and perhaps getRow methods.

Constructor Summary

Constructors

Constructor and Description
AbstractStarTable()

Method Summary

Modifier and Type	Method and Description
static int	checkedLongToInt(long lval) Convenience method to get an int value from a long.
void	close() The AbstractStarTable implementation of this method does nothing.
java.lang.Object	getCell(long irow, int icol) The AbstractStarTable implementation of this method throws an UnsupportedOperationException, since unless otherwise provided there is no random access.
java.util.List<ValueInfo>	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.
abstract int	getColumnCount() Returns the number of columns in this table.
abstract ColumnInfo	getColumnInfo(int icol) Returns the object describing the data in a given column.
java.lang.String	getName() Returns the name of this table, if it has one.
java.util.List<DescribedValue>	getParameters() Returns a list of table parameters, that is metadata items which pertain to the entire table.
java.lang.Object[]	getRow(long irow) The AbstractStarTable implementation of this method constructs a row by repeated invocation of getCell(long, int).
RowAccess	getRowAccess() Returns an object which can provide random access to this table's data, if random access is implemented.
abstract long	getRowCount() Returns the number of rows in this table, if known.
abstract RowSequence	getRowSequence() Returns an object which can iterate over all the rows in the table sequentially.
RowSplittable	getRowSplittable() Returns a default splittable which relies on table random access if available, or otherwise provides only sequential access (no splits).
java.net.URL	getURL() Returns the URL of this table, if it has one.
boolean	isRandom() The AbstractStarTable implementation of this method returns false.
void	setName(java.lang.String name) Sets the name for this table.
void	setParameters(java.util.List<DescribedValue> parameters) Sets the list of table parameters, that is items which pertain to the entire table.
void	setURL(java.net.URL url) Sets the URL for this table.

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

Constructor Detail

AbstractStarTable

public AbstractStarTable()

Method Detail

getColumnAuxDataInfos

public java.util.List<ValueInfo> 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. Subclasses should override this if they can do better, for instance providing an order for the keys.

Specified by:

getColumnAuxDataInfos in interface StarTable

Returns:

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

See Also:

DefaultValueInfo.getAuxData()

getParameters

public java.util.List<DescribedValue> getParameters()

Description copied from interface: StarTable

Returns a list of table parameters, that is metadata items which pertain to the entire table.

Specified by:

getParameters in interface StarTable

Returns:

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

setParameters

public void setParameters(java.util.List<DescribedValue> parameters)

Sets the list of table parameters, that is items which pertain to the entire table. Each element of the provided list parameters should be a DescribedValue object.

Parameters:

parameters - a List of DescribedValues pertaining to this table

getName

public java.lang.String getName()

Description copied from interface: StarTable

Returns the name of this table, if it has one. The meaning of the name is not defined, but it will typically be a short string of text indicating the identity of this table.

Specified by:

getName in interface StarTable

Returns:

a name for this table, or null if no suitable one exists

setName

public void setName(java.lang.String name)

Sets the name for this table.

Specified by:

setName in interface StarTable

Parameters:

name - the table name - may be null

getURL

public java.net.URL getURL()

Description copied from interface: StarTable

Returns the URL of this table, if it has one. A non-null return from this method indicates that this table is in some sense persistent.

Specified by:

getURL in interface StarTable

Returns:

the URL of this table, or null if none is known

setURL

public void setURL(java.net.URL url)

Sets the URL for this table.

Specified by:

setURL in interface StarTable

Parameters:

url - the URL where this table lives - may be null

checkedLongToInt

public static int checkedLongToInt(long lval)

Convenience method to get an int value from a long. Invokes Tables.checkedLongToInt(long).

isRandom

public boolean isRandom()

The AbstractStarTable implementation of this method returns false.

Specified by:

isRandom in interface StarTable

Returns:

true if table random access methods are available

getRowAccess

public RowAccess getRowAccess()
                       throws java.io.IOException

Description copied from interface: StarTable

Returns an object which can provide random access to this table's data, if random access is implemented. Each such returned object is safe for use within a single thread, but not in general from multiple threads concurrently.

Specified by:

getRowAccess in interface StarTable

Returns:

new RowAccess

Throws:

java.io.IOException - if there is an error setting up access

getRowSplittable

public RowSplittable getRowSplittable()
                               throws java.io.IOException

Returns a default splittable which relies on table random access if available, or otherwise provides only sequential access (no splits).

It is often possible to provide a better implementation than this.

Specified by:

getRowSplittable in interface StarTable

Returns:

Tables.getDefaultRowSplittable(this)

Throws:

java.io.IOException

See Also:

RowRunner

getCell

public java.lang.Object getCell(long irow,
                                int icol)
                         throws java.io.IOException

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

Specified by:

getCell in interface StarTable

Parameters:

irow - the index of the cell's row

icol - the index of the cell's column

Returns:

the contents of this cell

Throws:

java.io.IOException - if there is an error reading the data

getRow

public java.lang.Object[] getRow(long irow)
                          throws java.io.IOException

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

Specified by:

getRow in interface StarTable

Parameters:

irow - the index of the row to retrieve

Returns:

an array of the objects in each cell in row irow

Throws:

java.io.IOException - if there is an error reading the data

close

public void close()
           throws java.io.IOException

The AbstractStarTable implementation of this method does nothing.

Specified by:

close in interface java.io.Closeable

Specified by:

close in interface java.lang.AutoCloseable

Specified by:

close in interface StarTable

Throws:

java.io.IOException

getColumnInfo

public abstract 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

Parameters:

icol - the column for which header information is required

Returns:

a ValueInfo object for column icol

getColumnCount

public abstract int getColumnCount()

Description copied from interface: StarTable

Returns the number of columns in this table.

Specified by:

getColumnCount in interface StarTable

Returns:

the number of columns

getRowCount

public abstract 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

Returns:

the number of rows, or -1

getRowSequence

public abstract RowSequence getRowSequence()
                                    throws java.io.IOException

Description copied from interface: StarTable

Returns an object which can iterate over all the rows in the table sequentially. Each such returned object is safe for use within a single thread, but not in general from multiple threads concurrently.

Specified by:

getRowSequence in interface StarTable

Returns:

new RowSequence

Throws:

java.io.IOException - if there is an error providing access