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

Class UnionWriterImpl

java.lang.Object

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

All Implemented Interfaces:

ColumnWriter, VariantWriter, WriterEvents, WriterPosition

public class UnionWriterImpl
extends Object
implements VariantWriter, WriterEvents

Writer to a union vector.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static interface	UnionWriterImpl.UnionShim
static class	UnionWriterImpl.VariantObjectWriter

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

VariantWriter.VariantWriterListener

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

WriterEvents.ColumnWriterListener, WriterEvents.State

Constructor Summary

Constructors

Constructor and Description
UnionWriterImpl(ColumnMetadata schema)
UnionWriterImpl(ColumnMetadata schema, UnionVector vector, AbstractObjectWriter[] variants)

Method Summary

Modifier and Type	Method and Description
protected void	addMember(AbstractObjectWriter writer) Add a column writer to an existing union writer.
ObjectWriter	addMember(ColumnMetadata colSchema)
ObjectWriter	addMember(TypeProtos.MinorType type)
ArrayWriter	array()
void	bindIndex(ColumnWriterIndex index) Bind the writer to a writer index.
void	bindListener(VariantWriter.VariantWriterListener listener)
void	bindListener(WriterEvents.ColumnWriterListener listener) Bind a listener to the underlying vector writer.
void	bindShim(UnionWriterImpl.UnionShim shim)
void	copy(ColumnReader from) Copy a single value from the given reader, which must be of the same type as this writer.
void	dump(HierarchicalFormatter format)
WriterPosition	elementPosition()
void	endArrayValue() End a value.
void	endWrite() End a batch: finalize any vector values.
boolean	hasType(TypeProtos.MinorType type) Determine if the union vector has materialized storage for the given type.
ColumnWriterIndex	index()
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	lastWriteIndex() Return the last write position in the vector.
VariantWriter.VariantWriterListener	listener()
ObjectWriter	member(TypeProtos.MinorType type) Set the type of the present value and get the writer for that type.
ObjectWriter	memberWriter(TypeProtos.MinorType type) Create or retrieve a writer for the given type.
boolean	nullable() Whether this writer allows nulls.
void	postRollover() The vectors backing this writer rolled over.
void	preRollover() The vectors backing this vector are about to roll over.
void	restartRow() During a writer to a row, rewind the the current index position to restart the row.
int	rowStartIndex() Position within the vector of the first value for the current row.
void	saveRow() Saves a row.
ScalarWriter	scalar(TypeProtos.MinorType type)
ColumnMetadata	schema() Returns the schema of the column associated with this writer.
void	setNull() Set the current value to null.
void	setObject(Object value) Generic technique to write data as a generic Java object.
void	setType(TypeProtos.MinorType type) Explicitly set the type of the present value.
UnionWriterImpl.UnionShim	shim()
int	size() Returns the number of types in the variant.
void	startRow() Start a new row.
void	startWrite() Start a write (batch) operation.
WriterEvents.State	state()
TupleWriter	tuple()
ObjectType	type() Return the object (structure) type of this writer.
VariantMetadata	variantSchema() Metadata description of the variant that includes the set of types, along with extended properties of the types such as expected allocations sizes, expected array cardinality, etc.
int	writeIndex() Current write index for the writer.

Methods inherited from class java.lang.Object

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

Constructor Detail

UnionWriterImpl

public UnionWriterImpl(ColumnMetadata schema)

UnionWriterImpl

public UnionWriterImpl(ColumnMetadata schema,
                       UnionVector vector,
                       AbstractObjectWriter[] variants)

Method Detail

bindIndex

public void bindIndex(ColumnWriterIndex index)

Description copied from interface: WriterEvents

Bind the writer to a writer index.

Specified by:

bindIndex in interface WriterEvents

Parameters:

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

bindListener

public void bindListener(VariantWriter.VariantWriterListener listener)

bindListener

public void bindListener(WriterEvents.ColumnWriterListener listener)

Description copied from interface: WriterEvents

Bind a listener to the underlying vector writer. This listener reports on vector events (overflow, growth), and so is called only when the writer is backed by a vector. The listener is ignored (and never called) for dummy (non-projected) columns. If the column is compound (such as for a nullable or repeated column, or for a map), then the writer is bound to the individual components.

Specified by:

bindListener in interface WriterEvents

Parameters:

listener - the vector event listener to bind

state

public WriterEvents.State state()

index

public ColumnWriterIndex index()

listener

public VariantWriter.VariantWriterListener listener()

shim

public UnionWriterImpl.UnionShim shim()

elementPosition

public WriterPosition elementPosition()

bindShim

public void bindShim(UnionWriterImpl.UnionShim shim)

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

nullable

public boolean nullable()

Description copied from interface: ColumnWriter

Whether this writer allows nulls. This is not as simple as checking for the TypeProtos.DataMode.OPTIONAL type in the schema. List entries are nullable, if they are primitive, but not if they are maps or lists. Unions are nullable, regardless of cardinality.

Specified by:

nullable in interface ColumnWriter

Returns:

true if a call to ColumnWriter.setNull() is supported, false if not

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

variantSchema

public VariantMetadata variantSchema()

Description copied from interface: VariantWriter

Metadata description of the variant that includes the set of types, along with extended properties of the types such as expected allocations sizes, expected array cardinality, etc.

Specified by:

variantSchema in interface VariantWriter

Returns:

metadata for the variant

size

public int size()

Description copied from interface: VariantWriter

Returns the number of types in the variant. Some implementations (such as lists) impart special meaning to a variant with a single type.

Specified by:

size in interface VariantWriter

Returns:

number of types in the variant

hasType

public boolean hasType(TypeProtos.MinorType type)

Description copied from interface: VariantWriter

Determine if the union vector has materialized storage for the given type. (The storage will be created as needed during writing.)

Specified by:

hasType in interface VariantWriter

Parameters:

type - data type

Returns:

true if a value of the given type has been written and storage allocated (or storage was allocated implicitly), false otherwise

setNull

public void setNull()

Description copied from interface: ColumnWriter

Set the current value to null. Support depends on the underlying implementation: only nullable types support this operation. throws IllegalStateException if called on a non-nullable value.

Specified by:

setNull in interface ColumnWriter

memberWriter

public ObjectWriter memberWriter(TypeProtos.MinorType type)

Description copied from interface: VariantWriter

Create or retrieve a writer for the given type. Use this form when caching writers. This form does not set the type of the current row; call #setType(MinorType) per row when the writers are cached. This method can be called at any time as it does not depend on an active batch.

Specified by:

memberWriter in interface VariantWriter

Parameters:

type - the type of the writer to cache

Returns:

the writer for that type without setting the type of the current row.

member

public ObjectWriter member(TypeProtos.MinorType type)

Description copied from interface: VariantWriter

Set the type of the present value and get the writer for that type. Available only when a batch is active. Use this form to declare the type of the current row, and retrieve a writer for that value.

Specified by:

member in interface VariantWriter

Parameters:

type - type to set for the current row

Returns:

writer for the type just set

setType

public void setType(TypeProtos.MinorType type)

Description copied from interface: VariantWriter

Explicitly set the type of the present value. Use this when the writers are cached. The writer must already exist.

Specified by:

setType in interface VariantWriter

Parameters:

type - type to set for the current row

addMember

public ObjectWriter addMember(ColumnMetadata colSchema)

Specified by:

addMember in interface VariantWriter

addMember

public ObjectWriter addMember(TypeProtos.MinorType type)

Specified by:

addMember in interface VariantWriter

addMember

protected void addMember(AbstractObjectWriter writer)

Add a column writer to an existing union writer. Used for implementations that support "live" schema evolution: column discovery while writing. The corresponding metadata must already have been added to the schema. Called by the shim's addMember to do writer-level tasks.

Parameters:

writer - the column writer to add

scalar

public ScalarWriter scalar(TypeProtos.MinorType type)

Specified by:

scalar in interface VariantWriter

tuple

public TupleWriter tuple()

Specified by:

tuple in interface VariantWriter

array

public ArrayWriter array()

Specified by:

array in interface VariantWriter

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

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

restartRow

public void restartRow()

Description copied from interface: WriterEvents

During a writer to a row, rewind the the current index position to restart the row. Done when abandoning the current row, such as when filtering out a row at read time.

Specified by:

restartRow 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

preRollover

public void preRollover()

Description copied from interface: WriterEvents

The vectors backing this vector are about to roll over. Finish the current batch up to, but not including, the current row.

Specified by:

preRollover in interface WriterEvents

postRollover

public void postRollover()

Description copied from interface: WriterEvents

The vectors backing this writer rolled over. This means that data for the current row has been rolled over into a new vector. Offsets and indexes should be shifted based on the understanding that data for the current row now resides at the start of a new vector instead of its previous location elsewhere in an old vector.

Specified by:

postRollover in interface WriterEvents

endWrite

public void endWrite()

Description copied from interface: WriterEvents

End a batch: finalize any vector values.

Specified by:

endWrite in interface WriterEvents

lastWriteIndex

public int lastWriteIndex()

Description copied from interface: WriterPosition

Return the last write position in the vector. This may be the same as the writer index position (if the vector was written at that point), or an earlier point. In either case, this value points to the last valid value in the vector.

Specified by:

lastWriteIndex in interface WriterPosition

Returns:

index of the last valid value in the vector

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

copy

public void copy(ColumnReader from)

Description copied from interface: ColumnWriter

Copy a single value from the given reader, which must be of the same type as this writer.

Specified by:

copy in interface ColumnWriter

Parameters:

from - reader to provide the data

setObject

public void setObject(Object value)

Description copied from interface: ColumnWriter

Generic technique to write data as a generic Java object. The type of the object must match the target writer. Primarily for testing.

• Scalar: The type of the Java object must match the type of the target vector. String or byte[] can be used for Varchar vectors.
• Array: Write the array given an array of values. The object must be a Java array. The type of the array must match the type of element in the repeated vector. That is, if the vector is a Repeated Int, provide an int[] array.
• Tuple (map or row): The Java object must be an array of objects in which the members of the array have a 1:1 correspondence with the members of the tuple in the order defined by the writer metadata. That is, if the map is (Int, Varchar), provide a Object[] array like this: {10, "fred"}.
• Union: Uses the Java object type to determine the type of the backing vector. Creates a vector of the required type if needed.

Specified by:

setObject in interface ColumnWriter

Parameters:

value - value to write to the vector. The Java type of the object indicates the Drill storage type

dump

public void dump(HierarchicalFormatter format)

Specified by:

dump in interface WriterEvents