org.apache.flink.contrib.streaming.state

Class RocksDBAggregatingState<K,N,T,ACC,R>

java.lang.Object

org.apache.flink.contrib.streaming.state.AbstractRocksDBState<K,N,AggregatingState<T,R>,AggregatingStateDescriptor<T,ACC,R>,ACC>

org.apache.flink.contrib.streaming.state.RocksDBAggregatingState<K,N,T,ACC,R>

Type Parameters:

K - The type of the key

N - The type of the namespace

T - The type of the values that aggregated into the state

ACC - The type of the value stored in the state (the accumulator type)

R - The type of the value returned from the state

All Implemented Interfaces:

AggregatingState<T,R>, AppendingState<T,R>, MergingState<T,R>, State, InternalAggregatingState<N,T,R>, InternalAppendingState<N,T,R>, InternalKvState<N>, InternalMergingState<N,T,R>

public class RocksDBAggregatingState<K,N,T,ACC,R>
extends AbstractRocksDBState<K,N,AggregatingState<T,R>,AggregatingStateDescriptor<T,ACC,R>,ACC>
implements InternalAggregatingState<N,T,R>

An AggregatingState implementation that stores state in RocksDB.

Field Summary

Fields inherited from class org.apache.flink.contrib.streaming.state.AbstractRocksDBState

backend, columnFamily, keySerializationDataOutputView, keySerializationStream, stateDesc

Constructor Summary

Constructors

Constructor and Description
RocksDBAggregatingState(org.rocksdb.ColumnFamilyHandle columnFamily, TypeSerializer<N> namespaceSerializer, AggregatingStateDescriptor<T,ACC,R> stateDesc, RocksDBKeyedStateBackend<K> backend) Creates a new RocksDBFoldingState.

Method Summary

Modifier and Type	Method and Description
void	add(T value) Updates the operator state accessible by AppendingState.get() by adding the given value to the list of values.
R	get() Returns the current value for the state.
void	mergeNamespaces(N target, Collection<N> sources) Merges the state of the current key for the given source namespaces into the state of the target namespace.

Methods inherited from class org.apache.flink.contrib.streaming.state.AbstractRocksDBState

clear, getSerializedValue, readKeyWithGroupAndNamespace, setCurrentNamespace, writeCurrentKeyWithGroupAndNamespace, writeKeyWithGroupAndNamespace

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.flink.runtime.state.internal.InternalKvState

getSerializedValue, setCurrentNamespace

Methods inherited from interface org.apache.flink.api.common.state.State

clear

Constructor Detail

RocksDBAggregatingState

public RocksDBAggregatingState(org.rocksdb.ColumnFamilyHandle columnFamily,
                               TypeSerializer<N> namespaceSerializer,
                               AggregatingStateDescriptor<T,ACC,R> stateDesc,
                               RocksDBKeyedStateBackend<K> backend)

Creates a new RocksDBFoldingState.

Parameters:

namespaceSerializer - The serializer for the namespace.

stateDesc - The state identifier for the state. This contains the state name and aggregation function.

Method Detail

get

public R get()
      throws IOException

Description copied from interface: AppendingState

Returns the current value for the state. When the state is not partitioned the returned value is the same for all inputs in a given operator instance. If state partitioning is applied, the value returned depends on the current operator input, as the operator maintains an independent state for each partition.

NOTE TO IMPLEMENTERS: if the state is empty, then this method should return null.

Specified by:

get in interface AppendingState<T,R>

Returns:

The operator state value corresponding to the current input or null if the state is empty.

Throws:

IOException

add

public void add(T value)
         throws IOException

Description copied from interface: AppendingState

Updates the operator state accessible by AppendingState.get() by adding the given value to the list of values. The next time AppendingState.get() is called (for the same state partition) the returned state will represent the updated list.

Specified by:

add in interface AppendingState<T,R>

Parameters:

value - The new value for the state.

Throws:

IOException - Thrown if the system cannot access the state.

mergeNamespaces

public void mergeNamespaces(N target,
                            Collection<N> sources)
                     throws Exception

Description copied from interface: InternalMergingState

Merges the state of the current key for the given source namespaces into the state of the target namespace.

Specified by:

mergeNamespaces in interface InternalMergingState<N,T,R>

Parameters:

target - The target namespace where the merged state should be stored.

sources - The source namespaces whose state should be merged.

Throws:

Exception - The method may forward exception thrown internally (by I/O or functions).