PoissonSampler (Flink : Java 1.20.1-cp2 API)

java.lang.Object
- org.apache.flink.api.java.sampling.RandomSampler<T>
- - org.apache.flink.api.java.sampling.PoissonSampler<T>

Type Parameters:

T - The type of sample.
```
@Internal
public class PoissonSampler<T>
extends RandomSampler<T>
```
A sampler implementation based on the Poisson Distribution. While sampling elements with fraction and replacement, the selected number of each element follows a given poisson distribution.

See Also:

https://en.wikipedia.org/wiki/Poisson_distribution, Gap Sampling

Field Summary
- Fields inherited from class org.apache.flink.api.java.sampling.RandomSampler
  emptyIterable, EPSILON

Constructor Summary

Constructors
Constructor	Description
`PoissonSampler(double fraction)`	Create a poisson sampler which can sample elements with replacement.
`PoissonSampler(double fraction, long seed)`	Create a poisson sampler which can sample elements with replacement.

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`Iterator<T>`	`sample(Iterator<T> input)`	Sample the input elements, for each input element, generate its count following a poisson distribution.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Constructor Detail
  - PoissonSampler
```
public PoissonSampler(double fraction,
                      long seed)
```
    Create a poisson sampler which can sample elements with replacement.
    
    Parameters:
    
    fraction - The expected count of each element.
    
    seed - Random number generator seed for internal PoissonDistribution.
  - PoissonSampler
```
public PoissonSampler(double fraction)
```
    Create a poisson sampler which can sample elements with replacement.
    
    Parameters:
    
    fraction - The expected count of each element.
- Method Detail
  - sample
```
public Iterator<T> sample(Iterator<T> input)
```
    Sample the input elements, for each input element, generate its count following a poisson distribution.
    
    Specified by:
    
    sample in class RandomSampler<T>
    
    Parameters:
    
    input - Elements to be sampled.
    
    Returns:
    
    The sampled result which is lazy computed upon input elements.