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

Class MultiEvictionPolicy<DATA>

java.lang.Object

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

Type Parameters:

DATA - The type of data-items handled by the policies

All Implemented Interfaces:

Serializable, ActiveEvictionPolicy<DATA>, EvictionPolicy<DATA>

Direct Known Subclasses:

CloneableMultiEvictionPolicy

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

This policy provides the ability to use multiple eviction policies at the same time. It allows to use both, active and not active evictions.

See Also:

Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	MultiEvictionPolicy.EvictionStrategy This enum provides the different options for the eviction strategy.

Constructor Summary

Constructors

Constructor and Description
MultiEvictionPolicy(EvictionPolicy<DATA>... evictionPolicies) This policy provides the ability to use multiple eviction policies at the same time.
MultiEvictionPolicy(MultiEvictionPolicy.EvictionStrategy strategy, EvictionPolicy<DATA>... evictionPolicies) This policy provides the ability to use multiple eviction policies at the same time.

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

MultiEvictionPolicy

public MultiEvictionPolicy(EvictionPolicy<DATA>... evictionPolicies)

This policy provides the ability to use multiple eviction policies at the same time. It allows to use both, active and not active evictions. When using this constructor the MAX strategy is used by default. You can select other strategies using MultiEvictionPolicy(EvictionStrategy, EvictionPolicy...) .

Parameters:

evictionPolicies - Any active or not active eviction policies. Both types can be used at the same time.

MultiEvictionPolicy

public MultiEvictionPolicy(MultiEvictionPolicy.EvictionStrategy strategy,
                           EvictionPolicy<DATA>... evictionPolicies)

This policy provides the ability to use multiple eviction policies at the same time. It allows to use both, active and not active evictions.

Parameters:

strategy - the strategy to be used. See MultiEvictionPolicy.EvictionStrategy for a list of possible options.

evictionPolicies - Any active or not active eviction policies. Both types can be used at the same time.

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)