Package org.apache.druid.frame.write

Class FrameWriters

java.lang.Object

org.apache.druid.frame.write.FrameWriters

public class FrameWriters
extends Object

Outward-facing utility methods for FrameWriterFactory and FrameWriter users.

Method Summary

Modifier and Type	Method	Description
static FrameWriterFactory	makeFrameWriterFactory(FrameType frameType, MemoryAllocatorFactory allocatorFactory, RowSignature signature, List<KeyColumn> sortColumns)	Creates a FrameWriterFactory.
static RowSignature	sortableSignature(RowSignature signature, List<KeyColumn> keyColumns)	Returns a copy of "signature" with columns rearranged so the provided sortColumns appear as a prefix.

Methods inherited from class java.lang.Object

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

Method Detail

makeFrameWriterFactory

public static FrameWriterFactory makeFrameWriterFactory(FrameType frameType,
                                                        MemoryAllocatorFactory allocatorFactory,
                                                        RowSignature signature,
                                                        List<KeyColumn> sortColumns)

Creates a FrameWriterFactory.

Parameters:

frameType - type of the frames

allocatorFactory - supplier of allocators, which ultimately determine frame size. Frames are closed and written once the allocator runs out of memory.

signature - signature of the frames

sortColumns - sort columns for the frames. If nonempty, FrameSort.sort(org.apache.druid.frame.Frame, org.apache.druid.frame.read.FrameReader, java.util.List<org.apache.druid.frame.key.KeyColumn>) is used to sort the resulting frames.

sortableSignature

public static RowSignature sortableSignature(RowSignature signature,
                                             List<KeyColumn> keyColumns)

Returns a copy of "signature" with columns rearranged so the provided sortColumns appear as a prefix. Throws an error if any of the sortColumns are not present in the input signature, or if any of their types are unknown. This is useful because sort columns must appear