io.druid.segment.serde

Class ComplexMetricSerde

java.lang.Object

io.druid.segment.serde.ComplexMetricSerde

Direct Known Subclasses:

ApproximateHistogramFoldingSerde, DoublesSketchComplexMetricSerde, HyperUniquesSerde, SketchMergeComplexMetricSerde, VarianceSerde

public abstract class ComplexMetricSerde
extends Object

Constructor Summary

Constructors

Constructor and Description
ComplexMetricSerde()

Method Summary

Modifier and Type	Method and Description
abstract void	deserializeColumn(ByteBuffer buffer, ColumnBuilder builder) Deserializes a ByteBuffer and adds it to the ColumnBuilder.
Object	fromBytes(byte[] data, int start, int numBytes) Converts byte[] to intermediate representation of the aggregate.
abstract ComplexMetricExtractor	getExtractor()
abstract ObjectStrategy	getObjectStrategy() Deprecated.
GenericColumnSerializer	getSerializer(SegmentWriteOutMedium segmentWriteOutMedium, String column) This method provides the ability for a ComplexMetricSerde to control its own serialization.
abstract String	getTypeName()
com.google.common.base.Function<Object,Long>	inputSizeFn() Returns a function that can convert the Object provided by the ComplexColumn created through deserializeColumn into a number of expected input bytes to produce that object.
byte[]	toBytes(Object val) Converts intermediate representation of aggregate to byte[].

Methods inherited from class java.lang.Object

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

Constructor Detail

ComplexMetricSerde

public ComplexMetricSerde()

Method Detail

getTypeName

public abstract String getTypeName()

getExtractor

public abstract ComplexMetricExtractor getExtractor()

deserializeColumn

public abstract void deserializeColumn(ByteBuffer buffer,
                                       ColumnBuilder builder)

Deserializes a ByteBuffer and adds it to the ColumnBuilder. This method allows for the ComplexMetricSerde to implement it's own versioning scheme to allow for changes of binary format in a forward-compatible manner.

Parameters:

buffer - the buffer to deserialize

builder - ColumnBuilder to add the column to

getObjectStrategy

@Deprecated
public abstract ObjectStrategy getObjectStrategy()

Deprecated.

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.

Returns:

an ObjectStrategy as used by GenericIndexed

inputSizeFn

public com.google.common.base.Function<Object,Long> inputSizeFn()

Returns a function that can convert the Object provided by the ComplexColumn created through deserializeColumn into a number of expected input bytes to produce that object.

This is used to approximate the size of the input data via the SegmentMetadataQuery and does not need to be overridden if you do not care about the query.

Returns:

A function that can compute the size of the complex object or null if you cannot/do not want to compute it

toBytes

public byte[] toBytes(@Nullable
                      Object val)

Converts intermediate representation of aggregate to byte[].

Parameters:

val - intermediate representation of aggregate

Returns:

serialized intermediate representation of aggregate in byte[]

fromBytes

public Object fromBytes(byte[] data,
                        int start,
                        int numBytes)

Converts byte[] to intermediate representation of the aggregate.

Parameters:

data - array

start - offset in the byte array where to start reading

numBytes - number of bytes to read in given array

Returns:

intermediate representation of the aggregate

getSerializer

public GenericColumnSerializer getSerializer(SegmentWriteOutMedium segmentWriteOutMedium,
                                             String column)

This method provides the ability for a ComplexMetricSerde to control its own serialization. For large column (i.e columns greater than Integer.MAX) use (@link LargeColumnSupportedComplexColumnSerializer)

Returns:

an instance of GenericColumnSerializer used for serialization.