uk.ac.starlink.ttools.cone
Class LimitRowSink

java.lang.Object
  extended by uk.ac.starlink.ttools.cone.LimitRowSink
All Implemented Interfaces:
TableSink

public class LimitRowSink
extends Object
implements TableSink

TableSink wrapper implementation that truncates the row stream at a given maximum.

Since:
7 Nov 2014
Author:
Mark Taylor

Constructor Summary
LimitRowSink(TableSink base, long maxrow)
          Constructor.
 
Method Summary
 void acceptMetadata(StarTable table)
          Takes delivery of a row-less StarTable object which defines the metadata of the table to be transmitted.
 void acceptRow(Object[] row)
          Takes delivery of one row of data.
 void endRows()
          Signals that there are no more rows to be transmitted.
 boolean isTruncated()
          Indicates whether this sink has received any rows that it has refused to pass on to its base sink.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

LimitRowSink

public LimitRowSink(TableSink base,
                    long maxrow)
Constructor.

Parameters:
base - base sink
maxrow - maximum number of rows this sink will transmit to its base
Method Detail

acceptMetadata

public void acceptMetadata(StarTable table)
                    throws TableFormatException
Description copied from interface: TableSink
Takes delivery of a row-less StarTable object which defines the metadata of the table to be transmitted. If the number of rows that will be transmitted via subsequent calls to acceptRow is known, this value should be made available as the row count of meta (StarTable.getRowCount()); if it is not known, the row count should be -1. However, this object should not attempt to read any of meta's cell data.

The data to be transmitted in subsequent calls of acceptRow must match the metadata transmitted in this call in the same way that rows of a StarTable must match its own metadata (number and content clases of columns etc). If this sink cannot dispose of a table corresponding to meta then it may throw a TableFormatException - this may be the case if for instance meta has columns with types that this sink can't deal with.

Specified by:
acceptMetadata in interface TableSink
Parameters:
table - table metadata object
Throws:
TableFormatException - if this sink cannot accept table rows matching the given metadata

acceptRow

public void acceptRow(Object[] row)
               throws IOException
Description copied from interface: TableSink
Takes delivery of one row of data. row is an array of objects comprising the contents of one row of the table being transmitted. The number and classes of the elements of row are described by the metadata object previously accepted.

Specified by:
acceptRow in interface TableSink
Parameters:
row - table data row
Throws:
IOException

endRows

public void endRows()
             throws IOException
Description copied from interface: TableSink
Signals that there are no more rows to be transmitted.

Specified by:
endRows in interface TableSink
Throws:
IOException

isTruncated

public boolean isTruncated()
Indicates whether this sink has received any rows that it has refused to pass on to its base sink.

Returns:
true iff truncation has actually been applied so far


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