org.apache.hadoop.hive.common.histogram

Class KllHistogramEstimatorFactory

java.lang.Object

org.apache.hadoop.hive.common.histogram.KllHistogramEstimatorFactory

public class KllHistogramEstimatorFactory
extends Object

Method Summary

Modifier and Type	Method and Description
static KllHistogramEstimator	getEmptyHistogramEstimator() This method creates an empty histogram estimator with a KLL sketch with k=200.
static KllHistogramEstimator	getEmptyHistogramEstimator(int k) This method creates an empty histogram estimator with a KLL sketch of a given k parameter.
static KllHistogramEstimator	getEmptyHistogramEstimator(KllHistogramEstimator kllHistogramEstimator) This method creates an empty KLL histogram estimator, using the k parameter from the given estimator.
static KllHistogramEstimator	getKllHistogramEstimator(byte[] buf) This function deserializes the serialized KLL histogram estimator from a byte array.
static KllHistogramEstimator	getKllHistogramEstimator(byte[] buf, int start, int len) This function deserializes the serialized KLL histogram estimator from a byte array.

Methods inherited from class java.lang.Object

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

Method Detail

getKllHistogramEstimator

public static KllHistogramEstimator getKllHistogramEstimator(byte[] buf)

This function deserializes the serialized KLL histogram estimator from a byte array.

Parameters:

buf - to deserialize

Returns:

KLL histogram estimator

getKllHistogramEstimator

public static KllHistogramEstimator getKllHistogramEstimator(byte[] buf,
                                                             int start,
                                                             int len)

This function deserializes the serialized KLL histogram estimator from a byte array.

Parameters:

buf - to deserialize

start - start index for deserialization

len - start+len is deserialized

Returns:

KLL histogram estimator

getEmptyHistogramEstimator

public static KllHistogramEstimator getEmptyHistogramEstimator()

This method creates an empty histogram estimator with a KLL sketch with k=200.

Returns:

an empty histogram estimator with a KLL sketch with k=200

getEmptyHistogramEstimator

public static KllHistogramEstimator getEmptyHistogramEstimator(int k)

This method creates an empty histogram estimator with a KLL sketch of a given k parameter.

Parameters:

k - the KLL parameter k for initializing the sketch

Returns:

an empty histogram estimator with a KLL sketch of a given k parameter

getEmptyHistogramEstimator

public static KllHistogramEstimator getEmptyHistogramEstimator(KllHistogramEstimator kllHistogramEstimator)

This method creates an empty KLL histogram estimator, using the k parameter from the given estimator.

Parameters:

kllHistogramEstimator - the estimator used to build the new one

Returns:

an empty KLL histogram estimator, using the k parameter from the given estimator