uk.ac.starlink.table
Class RandomRowSequence

java.lang.Object
  uk.ac.starlink.table.RandomRowSequence

All Implemented Interfaces:

RowSequence

public class RandomRowSequence
extends java.lang.Object
implements RowSequence

An implementation of RowSequence which obtains its data from a random-access StarTable object.

Constructor Summary

RandomRowSequence(StarTable startab)
Constructs a RowSequence from a StarTable which must offer random access and know its number of rows.

Method Summary

void	close() Indicates that this sequence will not be required any more.
java.lang.Object	getCell(int icol) Returns the contents of a cell in the current row.
java.lang.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 advances the current row to the next one.

Methods inherited from class java.lang.Object

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

Constructor Detail

RandomRowSequence

public RandomRowSequence(StarTable startab)

Constructs a RowSequence from a StarTable which must offer random access and know its number of rows.

Parameters:

startab - the StarTable object providing the data

Throws:

java.lang.IllegalArgumentException - if startab.isRandom()==false or startab.getRowCount()<0

Method Detail

next

public boolean next()

Description copied from interface: RowSequence

Attempts to advances 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

Returns:

true iff this sequence has been advanced to the next row

getRow

public java.lang.Object[] getRow()
                          throws java.io.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 RowSequence

Returns:

an array of the objects in each cell in row irow

Throws:

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

getCell

public java.lang.Object getCell(int icol)
                         throws java.io.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 RowSequence

Returns:

the contents of cell icol in the current row

Throws:

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

close

public void 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 a close is undefined.

Specified by:

close in interface RowSequence