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

Class ActiveEvictionPolicyWrapper<DATA>

java.lang.Object

org.apache.flink.streaming.api.windowing.policy.ActiveEvictionPolicyWrapper<DATA>

Type Parameters:

DATA - The data type handled by this policy

All Implemented Interfaces:

Serializable, ActiveEvictionPolicy<DATA>, EvictionPolicy<DATA>

Direct Known Subclasses:

ActiveCloneableEvictionPolicyWrapper

public class ActiveEvictionPolicyWrapper<DATA>
extends Object
implements ActiveEvictionPolicy<DATA>

This ActiveEvictionPolicy wraps around a non active EvictionPolicy. It forwards all calls to ActiveEvictionPolicy.notifyEvictionWithFakeElement(Object, int) to EvictionPolicy.notifyEviction(Object, boolean, int) while the triggered parameter will be set to true.

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
ActiveEvictionPolicyWrapper(EvictionPolicy<DATA> nestedPolicy) Creates a wrapper which activates the eviction policy which is wrapped in.

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.
int	notifyEvictionWithFakeElement(Object datapoint, int bufferSize) Proves if and how many elements should be deleted from the element buffer.

Methods inherited from class java.lang.Object

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

Constructor Detail

ActiveEvictionPolicyWrapper

public ActiveEvictionPolicyWrapper(EvictionPolicy<DATA> nestedPolicy)

Creates a wrapper which activates the eviction policy which is wrapped in. This means that the nested policy will get called on fake elements as well as on real elements.

Parameters:

nestedPolicy - The policy which should be activated/wrapped in.

Method Detail

notifyEviction

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

Description copied from interface: EvictionPolicy

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.

Specified by:

notifyEviction in interface EvictionPolicy<DATA>

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

notifyEvictionWithFakeElement

public int notifyEvictionWithFakeElement(Object datapoint,
                                         int bufferSize)

Description copied from interface: ActiveEvictionPolicy

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. This method is only called with fake elements. Note: Fake elements are always considered as triggered. Therefore this method does not have a triggered parameter.

Specified by:

notifyEvictionWithFakeElement in interface ActiveEvictionPolicy<DATA>

Parameters:

datapoint - the current fake data point

bufferSize - the current size of the buffer (only real elements are counted)

Returns:

the number of elements to delete from the buffer (only real elements are counted)