Package org.apache.druid.query.aggregation

Class SerializablePairLongStringComplexMetricSerde

java.lang.Object

org.apache.druid.segment.serde.ComplexMetricSerde

org.apache.druid.query.aggregation.SerializablePairLongStringComplexMetricSerde

public class SerializablePairLongStringComplexMetricSerde
extends ComplexMetricSerde

The SerializablePairLongStringSerde serializes a Long-String pair (SerializablePairLongString). The serialization structure is: Long:Integer:String The Long is delta-encoded for the column in order to potentially reduce the size to an integer so it may be stored as: Integer:Integer:String

Future work: dictionary encoding of the String may be performed

The class is used on first/last String aggregators to store the time and the first/last string. [Integer|Long]:Integer:String -> delta:StringSize:StringData --(delta decoded)--> TimeStamp:StringSize:StringData (see )

Field Summary

Fields

Modifier and Type	Field	Description
static int	EXPECTED_VERSION
static String	TYPE_NAME

Constructor Summary

Constructors

Constructor	Description
SerializablePairLongStringComplexMetricSerde()
SerializablePairLongStringComplexMetricSerde(boolean compressionEnabled)

Method Summary

Modifier and Type	Method	Description
void	deserializeColumn(ByteBuffer buffer, ColumnBuilder columnBuilder)	ComplexMetricSerde.deserializeColumn(ByteBuffer, ColumnBuilder, ColumnConfig) should be used instead of this.
ComplexMetricExtractor<?>	getExtractor()
ObjectStrategy<SerializablePairLongString>	getObjectStrategy()	This is deprecated because its usage is going to be removed from the code.
GenericColumnSerializer<?>	getSerializer(SegmentWriteOutMedium segmentWriteOutMedium, String column, IndexSpec indexSpec)	This method provides the ability for a ComplexMetricSerde to control its own serialization.
String	getTypeName()
TypeStrategy<SerializablePairLongString>	getTypeStrategy()	Get a TypeStrategy to assist with writing individual complex values to a ByteBuffer.

Methods inherited from class org.apache.druid.segment.serde.ComplexMetricSerde

deserializeColumn, fromBytes, getSerializer, inputSizeFn, toBytes

Methods inherited from class java.lang.Object

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

Field Detail

EXPECTED_VERSION

public static final int EXPECTED_VERSION

See Also:

Constant Field Values

TYPE_NAME

public static final String TYPE_NAME

See Also:

Constant Field Values

Constructor Detail

SerializablePairLongStringComplexMetricSerde

public SerializablePairLongStringComplexMetricSerde()

SerializablePairLongStringComplexMetricSerde

public SerializablePairLongStringComplexMetricSerde(boolean compressionEnabled)

Method Detail

getTypeName

public String getTypeName()

Specified by:

getTypeName in class ComplexMetricSerde

getExtractor

public ComplexMetricExtractor<?> getExtractor()

Specified by:

getExtractor in class ComplexMetricSerde

deserializeColumn

public void deserializeColumn(ByteBuffer buffer,
                              ColumnBuilder columnBuilder)

Description copied from class: ComplexMetricSerde

ComplexMetricSerde.deserializeColumn(ByteBuffer, ColumnBuilder, ColumnConfig) should be used instead of this. This method is left for backward compatibility.

Overrides:

deserializeColumn in class ComplexMetricSerde

getObjectStrategy

public ObjectStrategy<SerializablePairLongString> getObjectStrategy()

Description copied from class: ComplexMetricSerde

This is deprecated because its usage is going to be removed from the code.

It was introduced before deserializeColumn() existed. This method creates the assumption that Druid knows how to interpret the actual column representation of the data, but I would much prefer that the ComplexMetricSerde objects be in charge of creating and interpreting the whole column, which is what deserializeColumn lets them do.

Specified by:

getObjectStrategy in class ComplexMetricSerde

Returns:

an ObjectStrategy as used by GenericIndexed

getTypeStrategy

public TypeStrategy<SerializablePairLongString> getTypeStrategy()

Description copied from class: ComplexMetricSerde

Get a TypeStrategy to assist with writing individual complex values to a ByteBuffer.

Overrides:

getTypeStrategy in class ComplexMetricSerde

See Also:

TypeStrategy

getSerializer

public GenericColumnSerializer<?> getSerializer(SegmentWriteOutMedium segmentWriteOutMedium,
                                                String column,
                                                IndexSpec indexSpec)

Description copied from class: ComplexMetricSerde

This method provides the ability for a ComplexMetricSerde to control its own serialization. Default implementation uses CompressedComplexColumnSerializer if IndexSpec.complexMetricCompression is not null or uncompressed/none, or LargeColumnSupportedComplexColumnSerializer if no compression is specified.

Overrides:

getSerializer in class ComplexMetricSerde

Returns:

an instance of GenericColumnSerializer used for serialization.