org.apache.drill.exec.vector.accessor.writer

Class ColumnWriterFactory

java.lang.Object

org.apache.drill.exec.vector.accessor.writer.ColumnWriterFactory

public class ColumnWriterFactory
extends Object

Gather generated writer classes into a set of class tables to allow rapid run-time creation of writers. Builds the writer and its object writer wrapper which binds the vector to the writer.

Compared to the reader factory, the writer factor is a bit more complex as it must handle both the projected ("real" writer) and unprojected ("dummy" writer) cases. Because of the way the various classes interact, it is cleaner to put the factory methods here rather than in the various writers, as is done in the case of the readers.

Constructor Summary

Constructors

Constructor and Description
ColumnWriterFactory()

Method Summary

Modifier and Type	Method and Description
static AbstractObjectWriter	buildColumnWriter(ColumnMetadata schema, ValueVector vector)
static AbstractObjectWriter	buildDummyColumnWriter(ColumnMetadata schema) Build a writer for a non-projected column.
static BaseScalarWriter	newWriter(ValueVector vector)

Methods inherited from class java.lang.Object

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

Constructor Detail

ColumnWriterFactory

public ColumnWriterFactory()

Method Detail

buildColumnWriter

public static AbstractObjectWriter buildColumnWriter(ColumnMetadata schema,
                                                     ValueVector vector)

buildDummyColumnWriter

public static AbstractObjectWriter buildDummyColumnWriter(ColumnMetadata schema)

Build a writer for a non-projected column.

Parameters:

schema - schema of the column

Returns:

a "dummy" writer for the column

newWriter

public static BaseScalarWriter newWriter(ValueVector vector)