uk.ac.starlink.table

Class WrapperRowSequence

java.lang.Object

uk.ac.starlink.table.WrapperRowSequence

All Implemented Interfaces:

Closeable, AutoCloseable, RowData, RowSequence, Sequence

Direct Known Subclasses:

ColumnQueryRowSequence, MappingRowSplittable, ProgressRowSequence, WrapperQuerySequence

public class WrapperRowSequence
extends Object
implements RowSequence

RowSequence which wraps another RowSequence. This class acts as a wrapper around an existing 'base' RowSequence object; all its methods are implemented by forwarding them to the corresponding methods of that base sequence.

This class is provided so that it can be extended by subclasses which modify the view of the base sequence in useful ways.

Author:

Mark Taylor (Starlink)

See Also:

WrapperStarTable

Field Summary

Fields

Modifier and Type	Field and Description
protected RowSequence	baseSeq

Constructor Summary

Constructors

Constructor and Description
WrapperRowSequence(RowSequence baseSeq) Constructs a new RowSequence based on a given one.
WrapperRowSequence(RowSequence baseSeq, RowData data) Constructs a new RowSequence based on a given one but with a supplied data access implementation.

Method Summary

Modifier and Type	Method and Description
void	close() Indicates that this sequence will not be required any more.
Object	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.
boolean	next() Attempts to advance the current row to the next one.
String	toString() Returns an indication of the wrapper structure of this sequence.

Methods inherited from class java.lang.Object

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

Field Detail

baseSeq

protected final RowSequence baseSeq

Constructor Detail

WrapperRowSequence

public WrapperRowSequence(RowSequence baseSeq)

Constructs a new RowSequence based on a given one.

Parameters:

baseSeq - the base row sequence

WrapperRowSequence

public WrapperRowSequence(RowSequence baseSeq,
                          RowData data)

Constructs a new RowSequence based on a given one but with a supplied data access implementation.

Parameters:

baseSeq - the base row access

data - RowData object whose methods will be used to implement the getCell and getRow methods

Method Detail

next

public boolean next()
             throws IOException

Description copied from interface: RowSequence

Attempts to advance the current row to the next one. If true is returned the attempt has been successful, and if false 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 the RowSequence.getCell(int) or RowSequence.getRow() methods.

Specified by:

next in interface RowSequence

Specified by:

next in interface Sequence

Returns:

true iff this sequence has been advanced to the next row

Throws:

IOException - if there is some error

getCell

public Object getCell(int icol)
               throws IOException

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 by getColumnInfo(icol).getContentClass(). An unchecked exception will be thrown if there is no current row (next has not yet been called).

Specified by:

getCell in interface RowData

Specified by:

getCell in interface RowSequence

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

public Object[] getRow()
                throws IOException

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 interface RowData

Specified by:

getRow in interface RowSequence

Returns:

an array of the objects in each cell in row irow

Throws:

IOException - if there is an error reading the data

close

public void close()
           throws IOException

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 a close is undefined.

Specified by:

close in interface Closeable

Specified by:

close in interface AutoCloseable

Specified by:

close in interface RowSequence

Throws:

IOException

toString

public String toString()

Returns an indication of the wrapper structure of this sequence.

Overrides:

toString in class Object

Returns:

string representation