org.apache.drill.exec.physical.resultSet.impl

Class ResultSetCopierImpl

java.lang.Object

org.apache.drill.exec.physical.resultSet.impl.ResultSetCopierImpl

All Implemented Interfaces:

ResultSetCopier

public class ResultSetCopierImpl
extends Object
implements ResultSetCopier

Field Summary

Fields

Modifier and Type	Field and Description
protected RowSetReader	rowReader

Constructor Summary

Constructors

Constructor and Description
ResultSetCopierImpl(BufferAllocator allocator, PullResultSetReader source)
ResultSetCopierImpl(BufferAllocator allocator, PullResultSetReader source, ResultSetOptionBuilder outputOptions)

Method Summary

Modifier and Type	Method and Description
void	close() Release resources, including any pending input batch and any non-harvested output batch.
void	copyAllRows() Copy all (remaining) input rows to the output.
boolean	copyNextRow() If copying rows one by one, copy the next row from the input.
void	copyRow(int posn) Copy a row at the given position.
VectorContainer	harvest() Obtain the output batch.
boolean	hasOutputRows() Reports if the output batch has rows.
boolean	isCopyPending() Helper method to determine if a copy is pending: more rows remain to be copied.
boolean	isOutputFull() Reports if the output batch is full and must be sent downstream.
boolean	nextInputBatch() Start the next input batch.
void	startOutputBatch() Start the next output batch.
protected void	verifyWritable()

Methods inherited from class java.lang.Object

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

Field Detail

rowReader

protected RowSetReader rowReader

Constructor Detail

ResultSetCopierImpl

public ResultSetCopierImpl(BufferAllocator allocator,
                           PullResultSetReader source)

ResultSetCopierImpl

public ResultSetCopierImpl(BufferAllocator allocator,
                           PullResultSetReader source,
                           ResultSetOptionBuilder outputOptions)

Method Detail

startOutputBatch

public void startOutputBatch()

Description copied from interface: ResultSetCopier

Start the next output batch.

Specified by:

startOutputBatch in interface ResultSetCopier

nextInputBatch

public boolean nextInputBatch()

Description copied from interface: ResultSetCopier

Start the next input batch. The input batch must be held by the ResultSetReader passed into the constructor.

Specified by:

nextInputBatch in interface ResultSetCopier

hasOutputRows

public boolean hasOutputRows()

Description copied from interface: ResultSetCopier

Reports if the output batch has rows. Useful after the end of input to determine if a partial output batch exists to send downstream.

Specified by:

hasOutputRows in interface ResultSetCopier

Returns:

true if the output batch has one or more rows

isOutputFull

public boolean isOutputFull()

Description copied from interface: ResultSetCopier

Reports if the output batch is full and must be sent downstream. The output batch can be full in the middle of a copy, in which case ResultSetCopier.isCopyPending() will also return true.

This function also returns true if a schema change occurred on the latest input row, in which case the partially-completed batch of the old schema must be flushed downstream.

Specified by:

isOutputFull in interface ResultSetCopier

Returns:

true if the output is full and must be harvested and sent downstream

verifyWritable

protected void verifyWritable()

copyNextRow

public boolean copyNextRow()

Description copied from interface: ResultSetCopier

If copying rows one by one, copy the next row from the input.

Specified by:

copyNextRow in interface ResultSetCopier

Returns:

true if more rows remain on the input, false if all rows are exhausted

copyRow

public void copyRow(int posn)

Description copied from interface: ResultSetCopier

Copy a row at the given position. For those cases in which random copying is needed, but a selection vector is not available. Note that this version is slow because of the need to reset indexes for every row. Better to use a selection vector, then copy sequentially.

Specified by:

copyRow in interface ResultSetCopier

Parameters:

posn - the input row position. If a selection vector is attached, then this is the selection vector position

copyAllRows

public void copyAllRows()

Description copied from interface: ResultSetCopier

Copy all (remaining) input rows to the output. If insufficient space exists in the output, does a partial copy, and ResultSetCopier.isCopyPending() will return true.

Specified by:

copyAllRows in interface ResultSetCopier

isCopyPending

public boolean isCopyPending()

Description copied from interface: ResultSetCopier

Helper method to determine if a copy is pending: more rows remain to be copied. If so, start a new output batch, which will finish the copy. Do that before start a new input batch.

Specified by:

isCopyPending in interface ResultSetCopier

Returns:

harvest

public VectorContainer harvest()

Description copied from interface: ResultSetCopier

Obtain the output batch. Returned as a vector container since the output will not have a selection vector.

Specified by:

harvest in interface ResultSetCopier

Returns:

a vector container holding the output batch

close

public void close()

Description copied from interface: ResultSetCopier

Release resources, including any pending input batch and any non-harvested output batch.

Specified by:

close in interface ResultSetCopier