org.apache.druid.frame.field

Class RowReader

java.lang.Object

org.apache.druid.frame.field.RowReader

public class RowReader
extends Object

Class for reading rows in the same format as used by FrameType.ROW_BASED. Stateless and immutable. Row format: - 4 bytes * rowLength: field *end* pointers (exclusive), relative to the start of the row, little-endian ints - N bytes * rowLength: fields written by FieldWriter implementations.

Constructor Summary

Constructors

Constructor and Description
RowReader(List<FieldReader> fieldReaders)

Method Summary

Modifier and Type	Method and Description
int	fieldCount()
FieldReader	fieldReader(int fieldNumber)
Object	readField(org.apache.datasketches.memory.Memory memory, long rowPosition, long rowLength, int fieldNumber) Read a particular field value as an object.
List<Object>	readRow(org.apache.datasketches.memory.Memory memory, long rowPosition, long rowLength) Read an entire row as a list of objects.

Methods inherited from class java.lang.Object

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

Constructor Detail

RowReader

public RowReader(List<FieldReader> fieldReaders)

Method Detail

fieldReader

public FieldReader fieldReader(int fieldNumber)

fieldCount

public int fieldCount()

readField

public Object readField(org.apache.datasketches.memory.Memory memory,
                        long rowPosition,
                        long rowLength,
                        int fieldNumber)

Read a particular field value as an object. For performance reasons, prefer FrameReader.makeCursorFactory(org.apache.druid.frame.Frame) for reading many rows out of a frame.

readRow

public List<Object> readRow(org.apache.datasketches.memory.Memory memory,
                            long rowPosition,
                            long rowLength)

Read an entire row as a list of objects. For performance reasons, prefer FrameReader.makeCursorFactory(org.apache.druid.frame.Frame) for reading many rows out of a frame.