com.facebook.presto.orc.reader

Interface SelectiveStreamReader

All Superinterfaces:

StreamReader

All Known Implementing Classes:

AbstractDecimalSelectiveStreamReader, BooleanSelectiveStreamReader, ByteSelectiveStreamReader, DoubleSelectiveStreamReader, FloatSelectiveStreamReader, ListSelectiveStreamReader, LongDecimalSelectiveStreamReader, LongDictionarySelectiveStreamReader, LongDirectSelectiveStreamReader, LongSelectiveStreamReader, MapDirectSelectiveStreamReader, MapFlatSelectiveStreamReader, MapSelectiveStreamReader, ShortDecimalSelectiveStreamReader, SliceDictionarySelectiveReader, SliceDirectSelectiveStreamReader, SliceSelectiveStreamReader, StructSelectiveStreamReader, TimestampSelectiveStreamReader

public interface SelectiveStreamReader
extends StreamReader

Method Summary

Modifier and Type	Method and Description
Block	getBlock(int[] positions, int positionCount) Return a subset of the values extracted during most recent read() for the specified positions Can be called at most once after each read().
BlockLease	getBlockView(int[] positions, int positionCount) Like getBlock(), but returns a temporary view of the data.
int[]	getReadPositions()
int	read(int offset, int[] positions, int positionCount) Extract values at the specified positions, apply filter and buffer the values that pass the filter.
void	throwAnyError(int[] positions, int positionCount) Throws any error that occurred while reading specified positions.

Methods inherited from interface com.facebook.presto.orc.reader.StreamReader

close, getRetainedSizeInBytes, startRowGroup, startStripe

Method Detail

read

int read(int offset,
         int[] positions,
         int positionCount)
  throws IOException

Extract values at the specified positions, apply filter and buffer the values that pass the filter.

Parameters:

positions - Monotonically increasing positions to read

positionCount - Number of valid positions in the positions array; may be less than the size of the array

Returns:

the number of positions that passed the filter

Throws:

IOException

getReadPositions

int[] getReadPositions()

Returns:

an array of positions that passed the filter during most recent read(); the return value of read() is the number of valid entries in this array; the return value is a strict subset of positions passed into read()

getBlock

Block getBlock(int[] positions,
               int positionCount)

Return a subset of the values extracted during most recent read() for the specified positions Can be called at most once after each read().

Parameters:

positions - Monotonically increasing positions to return; must be a strict subset of both the list of positions passed into read() and the list of positions returned from getReadPositions()

positionCount - Number of valid positions in the positions array; may be less than the size of the array

getBlockView

BlockLease getBlockView(int[] positions,
                        int positionCount)

Like getBlock(), but returns a temporary view of the data. The returned lease must be closed and block usage should be completed before subsequent invocations of getBlockView, getBlock, or read. May be called multiple times after each read(). On repeated invocation, the list of positions must be a strict subset of positions passed in the previous invocation.

throwAnyError

void throwAnyError(int[] positions,
                   int positionCount)

Throws any error that occurred while reading specified positions. Used by list and map readers to raise "subscript out of bounds" error.