org.apache.flink.streaming.api.windowing.policy

Interface EvictionPolicy<DATA>

Type Parameters:

DATA - the type of the data handled by this policy

All Superinterfaces:

Serializable

All Known Subinterfaces:

ActiveEvictionPolicy<DATA>, CloneableEvictionPolicy<DATA>

All Known Implementing Classes:

ActiveCloneableEvictionPolicyWrapper, ActiveEvictionPolicyWrapper, CloneableMultiEvictionPolicy, CountEvictionPolicy, DeltaPolicy, KeepAllEvictionPolicy, MultiEvictionPolicy, PunctuationPolicy, TimeEvictionPolicy, TumblingEvictionPolicy

public interface EvictionPolicy<DATA>
extends Serializable

An eviction policy specifies under which condition data points should be deleted from the buffer. Deletions must be done only in the order the elements arrived. Therefore, the policy only returns the number of elements to evict on each element arrival.

Method Summary

Modifier and Type	Method and Description
int	notifyEviction(DATA datapoint, boolean triggered, int bufferSize) Proves if and how many elements should be deleted from the element buffer.

Method Detail

notifyEviction

int notifyEviction(DATA datapoint,
                   boolean triggered,
                   int bufferSize)

Proves if and how many elements should be deleted from the element buffer. The eviction takes place after the trigger and after the call to the UDF but before the adding of the new data point.

Parameters:

datapoint - data point the data point which arrived

triggered - Information whether the UDF was triggered or not

bufferSize - The current size of the element buffer at the operator

Returns:

The number of elements to be deleted from the buffer