org.apache.drill.exec.vector

Class ZeroVector

java.lang.Object

org.apache.drill.exec.vector.ZeroVector

All Implemented Interfaces:

Closeable, AutoCloseable, Iterable<ValueVector>, ValueVector

public class ZeroVector
extends Object
implements ValueVector

Nested Class Summary

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

ValueVector.Accessor, ValueVector.Mutator

Field Summary

Fields

Modifier and Type	Field and Description
static ZeroVector	INSTANCE

Fields inherited from interface org.apache.drill.exec.vector.ValueVector

BITS_VECTOR_NAME, MAX_BUFFER_SIZE, MAX_ROW_COUNT, MIN_ROW_COUNT, OFFSETS_VECTOR_NAME, VALUES_VECTOR_NAME

Constructor Summary

Constructors

Constructor and Description
ZeroVector()

Method Summary

Modifier and Type	Method and Description
void	allocateNew() Allocate new buffers.
boolean	allocateNewSafe() Allocates new buffers.
void	clear() Release the underlying DrillBuf and reset the ValueVector to empty.
void	close() Alternative to clear().
void	collectLedgers(Set<AllocationManager.BufferLedger> ledgers) Add the ledgers underlying the buffers underlying the components of the vector to the set provided.
void	copyEntry(int toIndex, ValueVector from, int fromIndex)
void	exchange(ValueVector other) Exchange state with another value vector of the same type.
ValueVector.Accessor	getAccessor() Returns an accessor that is used to read from this vector instance.
int	getAllocatedSize() Returns the total size of buffers allocated by this vector.
BufferAllocator	getAllocator()
DrillBuf[]	getBuffers(boolean clear) Return the underlying buffers associated with this vector.
int	getBufferSize() Returns the number of bytes that is used by this vector instance.
int	getBufferSizeFor(int valueCount) Returns the number of bytes that is used by this vector if it holds the given number of values.
MaterializedField	getField() Get information about how this field is materialized.
UserBitShared.SerializedField	getMetadata() Get the metadata for this field.
ValueVector.Mutator	getMutator() Returns an mutator that is used to write to this vector instance.
int	getPayloadByteCount(int valueCount) Return the number of value bytes consumed by actual data.
FieldReader	getReader() Returns a field reader that supports reading values from this vector.
TransferPair	getTransferPair(BufferAllocator allocator) Returns a transfer pair, creating a new target vector of the same type.
TransferPair	getTransferPair(String ref, BufferAllocator allocator)
int	getValueCapacity() Returns the maximum number of values that can be stored in this vector instance.
Iterator<ValueVector>	iterator()
void	load(UserBitShared.SerializedField metadata, DrillBuf buffer) Load the data provided in the buffer.
TransferPair	makeTransferPair(ValueVector target) Returns a new transfer pair that is used to transfer underlying buffers into the target vector.
void	setInitialCapacity(int numRecords) Set the initial record capacity
void	toNullable(ValueVector nullableVector) Convert a non-nullable vector to nullable by shuffling the data from one to the other.

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.lang.Iterable

forEach, spliterator

Field Detail

INSTANCE

public static final ZeroVector INSTANCE

Constructor Detail

ZeroVector

public ZeroVector()

Method Detail

close

public void close()

Description copied from interface: ValueVector

Alternative to clear(). Allows use as an AutoCloseable in try-with-resources.

Specified by:

close in interface Closeable

Specified by:

close in interface AutoCloseable

Specified by:

close in interface ValueVector

clear

public void clear()

Description copied from interface: ValueVector

Release the underlying DrillBuf and reset the ValueVector to empty.

Specified by:

clear in interface ValueVector

getField

public MaterializedField getField()

Description copied from interface: ValueVector

Get information about how this field is materialized.

Specified by:

getField in interface ValueVector

getTransferPair

public TransferPair getTransferPair(BufferAllocator allocator)

Description copied from interface: ValueVector

Returns a transfer pair, creating a new target vector of the same type.

Specified by:

getTransferPair in interface ValueVector

getMetadata

public UserBitShared.SerializedField getMetadata()

Description copied from interface: ValueVector

Get the metadata for this field. Used in serialization

Specified by:

getMetadata in interface ValueVector

Returns:

FieldMetadata for this field.

iterator

public Iterator<ValueVector> iterator()

Specified by:

iterator in interface Iterable<ValueVector>

getBufferSize

public int getBufferSize()

Description copied from interface: ValueVector

Returns the number of bytes that is used by this vector instance. This is a bit of a misnomer. Returns the number of bytes used by data in this instance.

Specified by:

getBufferSize in interface ValueVector

getAllocatedSize

public int getAllocatedSize()

Description copied from interface: ValueVector

Returns the total size of buffers allocated by this vector. Has meaning only when vectors are directly allocated and each vector has its own buffer. Does not have meaning for vectors deserialized from the network or disk in which multiple vectors share the same vector.

Specified by:

getAllocatedSize in interface ValueVector

Returns:

allocated buffer size, in bytes

getBufferSizeFor

public int getBufferSizeFor(int valueCount)

Description copied from interface: ValueVector

Returns the number of bytes that is used by this vector if it holds the given number of values. The result will be the same as if Mutator.setValueCount() were called, followed by calling getBufferSize(), but without any of the closing side-effects that setValueCount() implies wrt finishing off the population of a vector. Some operations might wish to use this to determine how much memory has been used by a vector so far, even though it is not finished being populated.

Specified by:

getBufferSizeFor in interface ValueVector

Parameters:

valueCount - the number of values to assume this vector contains

Returns:

the buffer size if this vector is holding valueCount values

getBuffers

public DrillBuf[] getBuffers(boolean clear)

Description copied from interface: ValueVector

Return the underlying buffers associated with this vector. Note that this doesn't impact the reference counts for this buffer so it only should be used for in-context access. Also note that this buffer changes regularly thus external classes shouldn't hold a reference to it (unless they change it).

Specified by:

getBuffers in interface ValueVector

Parameters:

clear - Whether to clear vector before returning; the buffers will still be refcounted; but the returned array will be the only reference to them

Returns:

The underlying buffers that is used by this vector instance.

allocateNew

public void allocateNew()
                 throws OutOfMemoryException

Description copied from interface: ValueVector

Allocate new buffers. ValueVector implements logic to determine how much to allocate.

Specified by:

allocateNew in interface ValueVector

Throws:

OutOfMemoryException - Thrown if no memory can be allocated.

allocateNewSafe

public boolean allocateNewSafe()

Description copied from interface: ValueVector

Allocates new buffers. ValueVector implements logic to determine how much to allocate.

Specified by:

allocateNewSafe in interface ValueVector

Returns:

Returns true if allocation was successful.

getAllocator

public BufferAllocator getAllocator()

Specified by:

getAllocator in interface ValueVector

setInitialCapacity

public void setInitialCapacity(int numRecords)

Description copied from interface: ValueVector

Set the initial record capacity

Specified by:

setInitialCapacity in interface ValueVector

getValueCapacity

public int getValueCapacity()

Description copied from interface: ValueVector

Returns the maximum number of values that can be stored in this vector instance.

Specified by:

getValueCapacity in interface ValueVector

getTransferPair

public TransferPair getTransferPair(String ref,
                                    BufferAllocator allocator)

Specified by:

getTransferPair in interface ValueVector

makeTransferPair

public TransferPair makeTransferPair(ValueVector target)

Description copied from interface: ValueVector

Returns a new transfer pair that is used to transfer underlying buffers into the target vector.

Specified by:

makeTransferPair in interface ValueVector

getAccessor

public ValueVector.Accessor getAccessor()

Description copied from interface: ValueVector

Returns an accessor that is used to read from this vector instance.

Specified by:

getAccessor in interface ValueVector

getMutator

public ValueVector.Mutator getMutator()

Description copied from interface: ValueVector

Returns an mutator that is used to write to this vector instance.

Specified by:

getMutator in interface ValueVector

getReader

public FieldReader getReader()

Description copied from interface: ValueVector

Returns a field reader that supports reading values from this vector.

Specified by:

getReader in interface ValueVector

load

public void load(UserBitShared.SerializedField metadata,
                 DrillBuf buffer)

Description copied from interface: ValueVector

Load the data provided in the buffer. Typically used when deserializing from the wire.

Specified by:

load in interface ValueVector

Parameters:

metadata - Metadata used to decode the incoming buffer.

buffer - The buffer that contains the ValueVector.

copyEntry

public void copyEntry(int toIndex,
                      ValueVector from,
                      int fromIndex)

Specified by:

copyEntry in interface ValueVector

exchange

public void exchange(ValueVector other)

Description copied from interface: ValueVector

Exchange state with another value vector of the same type. Used to implement look-ahead writers.

Specified by:

exchange in interface ValueVector

collectLedgers

public void collectLedgers(Set<AllocationManager.BufferLedger> ledgers)

Description copied from interface: ValueVector

Add the ledgers underlying the buffers underlying the components of the vector to the set provided. Used to determine actual memory allocation.

Specified by:

collectLedgers in interface ValueVector

Parameters:

ledgers - set of ledgers to which to add ledgers for this vector

getPayloadByteCount

public int getPayloadByteCount(int valueCount)

Description copied from interface: ValueVector

Return the number of value bytes consumed by actual data.

Specified by:

getPayloadByteCount in interface ValueVector

toNullable

public void toNullable(ValueVector nullableVector)

Description copied from interface: ValueVector

Convert a non-nullable vector to nullable by shuffling the data from one to the other. Avoids the need to generate copy code just to change mode. If this vector is non-nullable, accepts a nullable dual (same minor type, different mode.) If the vector is non-nullable, or non-scalar, then throws an exception.

Specified by:

toNullable in interface ValueVector

Parameters:

nullableVector - nullable vector of the same minor type as this vector