Package org.elasticsearch.search.aggregations.metrics

Class AbstractLinearCounting

java.lang.Object

org.elasticsearch.search.aggregations.metrics.AbstractLinearCounting

public abstract class AbstractLinearCounting
extends Object

Linear counter, implemented based on pseudo code from http://static.googleusercontent.com/media/research.google.com/fr//pubs/archive/40671.pdf and its appendix https://docs.google.com/document/d/1gyjfMHy43U9OWBXxfaeG-3MjGzejW1dlpyMwEYAAWEI/view?fullscreen Trying to understand what this class does without having read the paper is considered adventurous. The algorithm just keep a record of all distinct values provided encoded as an integer.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static interface	AbstractLinearCounting.HashesIterator	Iterator over the hash values

Field Summary

Fields

Modifier and Type	Field	Description
static int	MAX_PRECISION
static int	MIN_PRECISION
protected int	p

Constructor Summary

Constructors

Constructor	Description
AbstractLinearCounting(int precision)

Method Summary

Modifier and Type	Method	Description
protected abstract int	addEncoded(long bucketOrd, int encoded)	Add encoded value to the linear counting.
long	cardinality(long bucketOrd)	Returns the current computed cardinality
int	collect(long bucketOrd, long hash)
int	precision()	Precision of the algorithm
protected abstract int	size(long bucketOrd)	number of values in the counter.
protected abstract AbstractLinearCounting.HashesIterator	values(long bucketOrd)	return the current values in the counter.

Methods inherited from class java.lang.Object

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

Field Details

MIN_PRECISION

public static final int MIN_PRECISION

See Also:

Constant Field Values

MAX_PRECISION

public static final int MAX_PRECISION

See Also:

Constant Field Values

p

protected final int p

Constructor Details

AbstractLinearCounting

public AbstractLinearCounting(int precision)

Method Details

addEncoded

protected abstract int addEncoded(long bucketOrd,
 int encoded)

Add encoded value to the linear counting. Implementor should only accept the value if it has not been seen before.

size

protected abstract int size(long bucketOrd)

number of values in the counter.

values

protected abstract AbstractLinearCounting.HashesIterator values(long bucketOrd)

return the current values in the counter.

collect

public int collect(long bucketOrd,
 long hash)

cardinality

public long cardinality(long bucketOrd)

Returns the current computed cardinality

precision

public int precision()

Precision of the algorithm