Package com.codahale.metrics
Class UniformReservoir
java.lang.Object
com.codahale.metrics.UniformReservoir
- All Implemented Interfaces:
Reservoir
A random sampling reservoir of a stream of
long
s. Uses Vitter's Algorithm R to produce a
statistically representative sample.- See Also:
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Field Summary
FieldsModifier and TypeFieldDescriptionprivate static final int
private final AtomicLong
private static final int
private final AtomicLongArray
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Constructor Summary
ConstructorsConstructorDescriptionCreates a newUniformReservoir
of 1028 elements, which offers a 99.9% confidence level with a 5% margin of error assuming a normal distribution.UniformReservoir
(int size) Creates a newUniformReservoir
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Method Summary
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Field Details
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DEFAULT_SIZE
private static final int DEFAULT_SIZE- See Also:
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BITS_PER_LONG
private static final int BITS_PER_LONG- See Also:
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count
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values
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Constructor Details
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UniformReservoir
public UniformReservoir()Creates a newUniformReservoir
of 1028 elements, which offers a 99.9% confidence level with a 5% margin of error assuming a normal distribution. -
UniformReservoir
public UniformReservoir(int size) Creates a newUniformReservoir
.- Parameters:
size
- the number of samples to keep in the sampling reservoir
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Method Details
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size
public int size()Description copied from interface:Reservoir
Returns the number of values recorded. -
update
public void update(long value) Description copied from interface:Reservoir
Adds a new recorded value to the reservoir. -
nextLong
private static long nextLong(long n) Get a pseudo-random long uniformly between 0 and n-1. Stolen fromRandom.nextInt()
.- Parameters:
n
- the bound- Returns:
- a value select randomly from the range
[0..n)
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getSnapshot
Description copied from interface:Reservoir
Returns a snapshot of the reservoir's values.- Specified by:
getSnapshot
in interfaceReservoir
- Returns:
- a snapshot of the reservoir's values
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