Package org.apache.drill.exec.physical.rowSet

Class RowSetReaderImpl

java.lang.Object

org.apache.drill.exec.vector.accessor.reader.AbstractTupleReader

org.apache.drill.exec.physical.rowSet.RowSetReaderImpl

All Implemented Interfaces:

RowSetReader, ColumnReader, ReaderEvents, TupleReader

public class RowSetReaderImpl
extends AbstractTupleReader
implements RowSetReader

Reader implementation for a row set.

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.drill.exec.vector.accessor.reader.AbstractTupleReader

AbstractTupleReader.TupleObjectReader

Field Summary

Fields

Modifier and Type	Field	Description
protected final ReaderIndex	readerIndex

Fields inherited from class org.apache.drill.exec.vector.accessor.reader.AbstractTupleReader

nullStateReader, readers

Constructor Summary

Constructors

Constructor	Description
RowSetReaderImpl(TupleMetadata schema, ReaderIndex index, List<AbstractObjectReader> readers)
RowSetReaderImpl(TupleMetadata schema, ReaderIndex index, AbstractObjectReader[] readers)

Method Summary

Modifier and Type	Method	Description
boolean	hasNext()	Convenience method which whether the next call to RowSetReader.next() will succeed.
int	hyperVectorIndex()	Batch index: 0 for a single batch, batch for the current row is a hyper-batch.
int	logicalIndex()	Gets the read position within the row set.
void	newBatch()	Bind the reader to a new batch of data.
boolean	next()	Advance to the next position.
int	offset()	The index of the underlying row which may be indexed by an SV2 or SV4.
void	rewind()	Reset the position to before the first row.
int	rowCount()	Total number of rows in the row set.
ColumnMetadata	schema()
void	setPosition(int index)	Sets the iteration position.
TupleMetadata	tupleSchema()

Methods inherited from class org.apache.drill.exec.vector.accessor.reader.AbstractTupleReader

array, array, bindBuffer, bindIndex, bindNullState, column, column, columnCount, dict, dict, getAsString, getObject, isNull, nullStateReader, reposition, scalar, scalar, tuple, tuple, type, type, type, variant, variant

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.drill.exec.vector.accessor.ColumnReader

getAsString, getObject, isNull, type

Methods inherited from interface org.apache.drill.exec.vector.accessor.TupleReader

array, array, column, column, columnCount, dict, dict, scalar, scalar, tuple, tuple, type, type, variant, variant

Field Details

readerIndex

protected final ReaderIndex readerIndex

Constructor Details

RowSetReaderImpl

public RowSetReaderImpl(TupleMetadata schema,
 ReaderIndex index,
 AbstractObjectReader[] readers)

RowSetReaderImpl

public RowSetReaderImpl(TupleMetadata schema,
 ReaderIndex index,
 List<AbstractObjectReader> readers)

Method Details

next

public boolean next()

Description copied from interface: RowSetReader

Advance to the next position. If the underlying row set has a selection vector, then moves one position in the selection vector, and to whichever data record is indexed.

Specified by:

next in interface RowSetReader

Returns:

true if another row is available, false if all rows have been read

hasNext

public boolean hasNext()

Description copied from interface: RowSetReader

Convenience method which whether the next call to RowSetReader.next() will succeed. Purely optional.

Specified by:

hasNext in interface RowSetReader

Returns:

true if there is another record to read, false if not

logicalIndex

public int logicalIndex()

Description copied from interface: RowSetReader

Gets the read position within the row set. If the row set has a selection vector, this is the position in that vector; the actual record location will likely differ. Use RowSetReader.offset() to get the actual row index.

Specified by:

logicalIndex in interface RowSetReader

Returns:

current iteration position

rowCount

public int rowCount()

Description copied from interface: RowSetReader

Total number of rows in the row set.

Specified by:

rowCount in interface RowSetReader

Returns:

total number of rows

offset

public int offset()

Description copied from interface: RowSetReader

The index of the underlying row which may be indexed by an SV2 or SV4.

Specified by:

offset in interface RowSetReader

Returns:

index of the underlying row

hyperVectorIndex

public int hyperVectorIndex()

Description copied from interface: RowSetReader

Batch index: 0 for a single batch, batch for the current row is a hyper-batch.

Specified by:

hyperVectorIndex in interface RowSetReader

Returns:

index of the batch for the current row

setPosition

public void setPosition(int index)

Description copied from interface: RowSetReader

Sets the iteration position. If the row set has a selection vector, this sets the index within that vector. The index must be from -1 to the RowSetReader.rowCount() - 1. Set the value to one less than the position to be read in the next call to RowSetReader.next(). An index of -1 means before the first row.

Specified by:

setPosition in interface RowSetReader

Parameters:

index - the desired index position

schema

public ColumnMetadata schema()

Specified by:

schema in interface ColumnReader

tupleSchema

public TupleMetadata tupleSchema()

Specified by:

tupleSchema in interface TupleReader

rewind

public void rewind()

Description copied from interface: RowSetReader

Reset the position to before the first row. Convenient method which is the same as setPosition(-1).

Specified by:

rewind in interface RowSetReader

newBatch

public void newBatch()

Description copied from interface: RowSetReader

Bind the reader to a new batch of data. The vectors are unchanged, but the buffers are different. Assumes the schema has not changed: the columns and selection vector mode remain unchanged; only the buffers changed. If the schema changes, discard this reader and rebuild a new one.

Specified by:

newBatch in interface RowSetReader