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

Class AbstractScalarWriterImpl

java.lang.Object

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

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

All Implemented Interfaces:

ColumnWriter, ScalarWriter, ValueWriter, WriterEvents, WriterPosition

Direct Known Subclasses:

BaseScalarWriter, DummyScalarWriter, NullableScalarWriter

public abstract class AbstractScalarWriterImpl
extends AbstractScalarWriter
implements WriterEvents

Column writer implementation that acts as the basis for the generated, vector-specific implementations. All set methods throw an exception; subclasses simply override the supported method(s).

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	AbstractScalarWriterImpl.ScalarObjectWriter Wraps a scalar writer and its event handler to provide a uniform JSON-like interface for all writer types.

Nested classes/interfaces inherited from interface org.apache.drill.exec.vector.accessor.writer.WriterEvents

WriterEvents.ColumnWriterListener, WriterEvents.State

Field Summary

Fields

Modifier and Type	Field and Description
protected ColumnMetadata	schema
protected ColumnWriterIndex	vectorIndex Indicates the position in the vector to write.

Constructor Summary

Constructors

Constructor and Description
AbstractScalarWriterImpl()

Method Summary

Modifier and Type	Method and Description
void	bindIndex(ColumnWriterIndex vectorIndex) Bind the writer to a writer index.
void	bindSchema(ColumnMetadata schema)
void	dump(HierarchicalFormatter format)
void	endArrayValue() End a value.
boolean	isProjected() Whether this writer is projected (is backed by a materialized vector), or is unprojected (is just a dummy writer.) In most cases, clients can ignore whether the column is projected and just write to the writer.
int	rowStartIndex() Position within the vector of the first value for the current row.
void	saveRow() Saves a row.
ColumnMetadata	schema() Returns the schema of the column associated with this writer.
void	startRow() Start a new row.
void	startWrite() Start a write (batch) operation.
ObjectType	type() Return the object (structure) type of this writer.
abstract BaseDataValueVector	vector()
int	writeIndex() Current write index for the writer.

Methods inherited from class org.apache.drill.exec.vector.accessor.writer.AbstractScalarWriter

bindListener, conversionError, extendedType, setObject, toString

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.drill.exec.vector.accessor.writer.WriterEvents

bindListener, endWrite, postRollover, preRollover, restartRow

Methods inherited from interface org.apache.drill.exec.vector.accessor.WriterPosition

lastWriteIndex

Methods inherited from interface org.apache.drill.exec.vector.accessor.ScalarWriter

setDefaultValue, valueType

Methods inherited from interface org.apache.drill.exec.vector.accessor.ColumnWriter

copy, nullable, setNull

Methods inherited from interface org.apache.drill.exec.vector.accessor.ValueWriter

appendBytes, setBoolean, setBytes, setDate, setDecimal, setDouble, setFloat, setInt, setLong, setNull, setPeriod, setString, setTime, setTimestamp, setValue

Field Detail

schema

protected ColumnMetadata schema

vectorIndex

protected ColumnWriterIndex vectorIndex

Indicates the position in the vector to write. Set via an object so that all writers (within the same subtree) can agree on the write position. For example, all top-level, simple columns see the same row index. All columns within a repeated map see the same (inner) index, etc.

Constructor Detail

AbstractScalarWriterImpl

public AbstractScalarWriterImpl()

Method Detail

type

public ObjectType type()

Description copied from interface: ColumnWriter

Return the object (structure) type of this writer.

Specified by:

type in interface ColumnWriter

Returns:

type indicating if this is a scalar, tuple or array

bindSchema

public void bindSchema(ColumnMetadata schema)

bindIndex

public void bindIndex(ColumnWriterIndex vectorIndex)

Description copied from interface: WriterEvents

Bind the writer to a writer index.

Specified by:

bindIndex in interface WriterEvents

Parameters:

vectorIndex - the writer index (top level or nested for arrays)

rowStartIndex

public int rowStartIndex()

Description copied from interface: WriterPosition

Position within the vector of the first value for the current row. Note that this is always the first value for the row, even for a writer deeply nested within a hierarchy of arrays. (The first position for the current array is not exposed in this API.)

Specified by:

rowStartIndex in interface WriterPosition

Returns:

the vector offset of the first value for the current row

writeIndex

public int writeIndex()

Description copied from interface: WriterPosition

Current write index for the writer. This is the global array location for arrays, same as the row index for top-level columns.

Specified by:

writeIndex in interface WriterPosition

Returns:

current write index

schema

public ColumnMetadata schema()

Description copied from interface: ColumnWriter

Returns the schema of the column associated with this writer.

Specified by:

schema in interface ColumnWriter

Returns:

schema for this writer's column

vector

public abstract BaseDataValueVector vector()

startWrite

public void startWrite()

Description copied from interface: WriterEvents

Start a write (batch) operation. Performs any vector initialization required at the start of a batch (especially for offset vectors.)

Specified by:

startWrite in interface WriterEvents

startRow

public void startRow()

Description copied from interface: WriterEvents

Start a new row. To be called only when a row is not active. To restart a row, call WriterEvents.restartRow() instead.

Specified by:

startRow in interface WriterEvents

endArrayValue

public void endArrayValue()

Description copied from interface: WriterEvents

End a value. Similar to WriterEvents.saveRow(), but the save of a value is conditional on saving the row. This version is primarily of use in tuples nested inside arrays: it saves each tuple within the array, advancing to a new position in the array. The update of the array's offset vector based on the cumulative value saves is done when saving the row.

Specified by:

endArrayValue in interface WriterEvents

saveRow

public void saveRow()

Description copied from interface: WriterEvents

Saves a row. Commits offset vector locations and advances each to the next position. Can be called only when a row is active.

Specified by:

saveRow in interface WriterEvents

isProjected

public boolean isProjected()

Description copied from interface: ColumnWriter

Whether this writer is projected (is backed by a materialized vector), or is unprojected (is just a dummy writer.) In most cases, clients can ignore whether the column is projected and just write to the writer. This flag handles those special cases where it is helpful to know if the column is projected or not.

Specified by:

isProjected in interface ColumnWriter

dump

public void dump(HierarchicalFormatter format)

Specified by:

dump in interface WriterEvents