uk.ac.starlink.ttools
Class SequentialJELRowReader

java.lang.Object
  |
  +--gnu.jel.DVMap
        |
        +--uk.ac.starlink.ttools.JELRowReader
              |
              +--uk.ac.starlink.ttools.SequentialJELRowReader
All Implemented Interfaces:
gnu.jel.DVResolver, RowSequence

public class SequentialJELRowReader
extends JELRowReader
implements RowSequence

Implements JELRowReader for sequential access to a table. This class also implements RowSequence, and this object should be treated in the same way as a row sequence taken out on its table, that is iteration should proceed using the next and close methods.

Since:
8 Feb 2005

Field Summary
 
Fields inherited from class uk.ac.starlink.ttools.JELRowReader
COLUMN_ID_CHAR, NULL_QUERY_PREFIX
 
Constructor Summary
SequentialJELRowReader(StarTable table)
          Constructs a new row reader for sequential access.
 
Method Summary
 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.
 long getCurrentRow()
          Returns the index of the row on which evaluations are currently taking place.
 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 uk.ac.starlink.ttools.JELRowReader
evaluate, getBooleanArrayProperty, getBooleanProperty, getBooleanProperty, getByteArrayProperty, getByteProperty, getByteProperty, getCharArrayProperty, getCharProperty, getDateArrayProperty, getDateProperty, getDoubleArrayProperty, getDoubleProperty, getFloatArrayProperty, getFloatProperty, getIntArrayProperty, getIntProperty, getLongArrayProperty, getLongProperty, getLongProperty, getObjectArrayProperty, getObjectProperty, getObjectProperty, getShortArrayProperty, getShortProperty, getStringArrayProperty, getStringProperty, getTypeName, translate
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

SequentialJELRowReader

public SequentialJELRowReader(StarTable table)
                       throws IOException
Constructs a new row reader for sequential access. This constructor also takes out a row sequence on table.

Parameters:
table - table to read
Method Detail

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 RowSequence
Specified by:
getCell in class JELRowReader
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 RowSequence
Returns:
an array of the objects in each cell in row irow
Throws:
IOException - if there is an error reading the data

next

public boolean next()
             throws IOException
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
Throws:
IOException - if there is some error

getCurrentRow

public long getCurrentRow()
Description copied from class: JELRowReader
Returns the index of the row on which evaluations are currently taking place.

Specified by:
getCurrentRow in class JELRowReader
Returns:
row index (first row is 0)

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 RowSequence
IOException

Copyright © 2004 CLRC: Central Laboratory of the Research Councils. All rights reserved.