org.apache.flink.state.api

Class WindowReader<W extends org.apache.flink.streaming.api.windowing.windows.Window>

java.lang.Object

org.apache.flink.state.api.WindowReader<W>

Type Parameters:

W - The type of Window.

@PublicEvolving
public class WindowReader<W extends org.apache.flink.streaming.api.windowing.windows.Window>
extends Object

This class provides entry points for reading keyed state written out using the WindowOperator.

Method Summary

Modifier and Type	Method and Description
<K,T,ACC,R> org.apache.flink.api.java.operators.DataSource<R>	aggregate(String uid, org.apache.flink.api.common.functions.AggregateFunction<T,ACC,R> aggregateFunction, org.apache.flink.api.common.typeinfo.TypeInformation<K> keyType, org.apache.flink.api.common.typeinfo.TypeInformation<ACC> accType, org.apache.flink.api.common.typeinfo.TypeInformation<R> outputType) Reads window state generated using an AggregateFunction.
<K,T,ACC,R,OUT> org.apache.flink.api.java.operators.DataSource<OUT>	aggregate(String uid, org.apache.flink.api.common.functions.AggregateFunction<T,ACC,R> aggregateFunction, WindowReaderFunction<R,OUT,K,W> readerFunction, org.apache.flink.api.common.typeinfo.TypeInformation<K> keyType, org.apache.flink.api.common.typeinfo.TypeInformation<ACC> accType, org.apache.flink.api.common.typeinfo.TypeInformation<OUT> outputType) Reads window state generated using an AggregateFunction.
EvictingWindowReader<W>	evictor() Reads from a window that uses an evictor.
<K,T,OUT> org.apache.flink.api.java.operators.DataSource<OUT>	process(String uid, WindowReaderFunction<T,OUT,K,W> readerFunction, org.apache.flink.api.common.typeinfo.TypeInformation<K> keyType, org.apache.flink.api.common.typeinfo.TypeInformation<T> stateType, org.apache.flink.api.common.typeinfo.TypeInformation<OUT> outputType) Reads window state generated without any preaggregation such as WindowedStream#apply and WindowedStream#process.
<T,K> org.apache.flink.api.java.operators.DataSource<T>	reduce(String uid, org.apache.flink.api.common.functions.ReduceFunction<T> function, org.apache.flink.api.common.typeinfo.TypeInformation<K> keyType, org.apache.flink.api.common.typeinfo.TypeInformation<T> reduceType) Reads window state generated using a ReduceFunction.
<K,T,OUT> org.apache.flink.api.java.operators.DataSource<OUT>	reduce(String uid, org.apache.flink.api.common.functions.ReduceFunction<T> function, WindowReaderFunction<T,OUT,K,W> readerFunction, org.apache.flink.api.common.typeinfo.TypeInformation<K> keyType, org.apache.flink.api.common.typeinfo.TypeInformation<T> reduceType, org.apache.flink.api.common.typeinfo.TypeInformation<OUT> outputType) Reads window state generated using a ReduceFunction.

Methods inherited from class java.lang.Object

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

Method Detail

evictor

public EvictingWindowReader<W> evictor()

Reads from a window that uses an evictor.

reduce

public <T,K> org.apache.flink.api.java.operators.DataSource<T> reduce(String uid,
                                                                      org.apache.flink.api.common.functions.ReduceFunction<T> function,
                                                                      org.apache.flink.api.common.typeinfo.TypeInformation<K> keyType,
                                                                      org.apache.flink.api.common.typeinfo.TypeInformation<T> reduceType)
                                                               throws IOException

Reads window state generated using a ReduceFunction.

Type Parameters:

T - The type of the reduce function.

K - The key type of the operator.

Parameters:

uid - The uid of the operator.

function - The reduce function used to create the window.

keyType - The key type of the window.

reduceType - The type information of the reduce function.

Returns:

A DataSet of objects read from keyed state.

Throws:

IOException - If savepoint does not contain the specified uid.

reduce

public <K,T,OUT> org.apache.flink.api.java.operators.DataSource<OUT> reduce(String uid,
                                                                            org.apache.flink.api.common.functions.ReduceFunction<T> function,
                                                                            WindowReaderFunction<T,OUT,K,W> readerFunction,
                                                                            org.apache.flink.api.common.typeinfo.TypeInformation<K> keyType,
                                                                            org.apache.flink.api.common.typeinfo.TypeInformation<T> reduceType,
                                                                            org.apache.flink.api.common.typeinfo.TypeInformation<OUT> outputType)
                                                                     throws IOException

Reads window state generated using a ReduceFunction.

Type Parameters:

K - The type of the key.

T - The type of the reduce function.

OUT - The output type of the reduce function.

Parameters:

uid - The uid of the operator.

function - The reduce function used to create the window.

readerFunction - The window reader function.

keyType - The key type of the window.

reduceType - The type information of the reduce function.

outputType - The output type of the reader function.

Returns:

A DataSet of objects read from keyed state.

Throws:

IOException - If savepoint does not contain the specified uid.

aggregate

public <K,T,ACC,R> org.apache.flink.api.java.operators.DataSource<R> aggregate(String uid,
                                                                               org.apache.flink.api.common.functions.AggregateFunction<T,ACC,R> aggregateFunction,
                                                                               org.apache.flink.api.common.typeinfo.TypeInformation<K> keyType,
                                                                               org.apache.flink.api.common.typeinfo.TypeInformation<ACC> accType,
                                                                               org.apache.flink.api.common.typeinfo.TypeInformation<R> outputType)
                                                                        throws IOException

Reads window state generated using an AggregateFunction.

Type Parameters:

K - The type of the key.

T - The type of the values that are aggregated.

ACC - The type of the accumulator (intermediate aggregate state).

R - The type of the aggregated result.

Parameters:

uid - The uid of the operator.

aggregateFunction - The aggregate function used to create the window.

keyType - The key type of the window.

accType - The type information of the accumulator function.

outputType - The output type of the reader function.

Returns:

A DataSet of objects read from keyed state.

Throws:

IOException - If savepoint does not contain the specified uid.

aggregate

public <K,T,ACC,R,OUT> org.apache.flink.api.java.operators.DataSource<OUT> aggregate(String uid,
                                                                                     org.apache.flink.api.common.functions.AggregateFunction<T,ACC,R> aggregateFunction,
                                                                                     WindowReaderFunction<R,OUT,K,W> readerFunction,
                                                                                     org.apache.flink.api.common.typeinfo.TypeInformation<K> keyType,
                                                                                     org.apache.flink.api.common.typeinfo.TypeInformation<ACC> accType,
                                                                                     org.apache.flink.api.common.typeinfo.TypeInformation<OUT> outputType)
                                                                              throws IOException

Reads window state generated using an AggregateFunction.

Type Parameters:

K - The type of the key.

T - The type of the values that are aggregated.

ACC - The type of the accumulator (intermediate aggregate state).

R - The type of the aggregated result.

OUT - The output type of the reader function.

Parameters:

uid - The uid of the operator.

aggregateFunction - The aggregate function used to create the window.

readerFunction - The window reader function.

keyType - The key type of the window.

accType - The type information of the accumulator function.

outputType - The output type of the reader function.

Returns:

A DataSet of objects read from keyed state.

Throws:

IOException - If savepoint does not contain the specified uid.

process

public <K,T,OUT> org.apache.flink.api.java.operators.DataSource<OUT> process(String uid,
                                                                             WindowReaderFunction<T,OUT,K,W> readerFunction,
                                                                             org.apache.flink.api.common.typeinfo.TypeInformation<K> keyType,
                                                                             org.apache.flink.api.common.typeinfo.TypeInformation<T> stateType,
                                                                             org.apache.flink.api.common.typeinfo.TypeInformation<OUT> outputType)
                                                                      throws IOException

Reads window state generated without any preaggregation such as WindowedStream#apply and WindowedStream#process.

Type Parameters:

K - The type of the key.

T - The type of the records stored in state.

OUT - The output type of the reader function.

Parameters:

uid - The uid of the operator.

readerFunction - The window reader function.

keyType - The key type of the window.

stateType - The type of records stored in state.

outputType - The output type of the reader function.

Returns:

A DataSet of objects read from keyed state.

Throws:

IOException - If the savepoint does not contain the specified uid.