org.apache.flink.table.runtime.operators.aggregate

Class GroupAggFunction

java.lang.Object

org.apache.flink.api.common.functions.AbstractRichFunction

org.apache.flink.streaming.api.functions.KeyedProcessFunction<RowData,RowData,RowData>

org.apache.flink.table.runtime.operators.aggregate.GroupAggFunction

All Implemented Interfaces:

Serializable, Function, RichFunction

public class GroupAggFunction
extends KeyedProcessFunction<RowData,RowData,RowData>

Aggregate Function used for the groupby (without window) aggregate.

See Also:

Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.flink.streaming.api.functions.KeyedProcessFunction

KeyedProcessFunction.Context, KeyedProcessFunction.OnTimerContext

Constructor Summary

Constructors

Constructor and Description
GroupAggFunction(GeneratedAggsHandleFunction genAggsHandler, GeneratedRecordEqualiser genRecordEqualiser, LogicalType[] accTypes, int indexOfCountStar, boolean generateUpdateBefore, long stateRetentionTime) Creates a GroupAggFunction.

Method Summary

Modifier and Type	Method and Description
void	close() Tear-down method for the user code.
void	open(Configuration parameters) Initialization method for the function.
void	processElement(RowData input, KeyedProcessFunction.Context ctx, Collector<RowData> out) Process one element from the input stream.

Methods inherited from class org.apache.flink.streaming.api.functions.KeyedProcessFunction

onTimer

Methods inherited from class org.apache.flink.api.common.functions.AbstractRichFunction

getIterationRuntimeContext, getRuntimeContext, setRuntimeContext

Methods inherited from class java.lang.Object

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

Constructor Detail

GroupAggFunction

public GroupAggFunction(GeneratedAggsHandleFunction genAggsHandler,
                        GeneratedRecordEqualiser genRecordEqualiser,
                        LogicalType[] accTypes,
                        int indexOfCountStar,
                        boolean generateUpdateBefore,
                        long stateRetentionTime)

Creates a GroupAggFunction.

Parameters:

genAggsHandler - The code generated function used to handle aggregates.

genRecordEqualiser - The code generated equaliser used to equal RowData.

accTypes - The accumulator types.

indexOfCountStar - The index of COUNT(*) in the aggregates. -1 when the input doesn't contain COUNT(*), i.e. doesn't contain retraction messages. We make sure there is a COUNT(*) if input stream contains retraction.

generateUpdateBefore - Whether this operator will generate UPDATE_BEFORE messages.

stateRetentionTime - state idle retention time which unit is MILLISECONDS.

Method Detail

open

public void open(Configuration parameters)
          throws Exception

Description copied from interface: RichFunction

Initialization method for the function. It is called before the actual working methods (like map or join) and thus suitable for one time setup work. For functions that are part of an iteration, this method will be invoked at the beginning of each iteration superstep.

The configuration object passed to the function can be used for configuration and initialization. The configuration contains all parameters that were configured on the function in the program composition.

 public class MyFilter extends RichFilterFunction<String> {

     private String searchString;

     public void open(Configuration parameters) {
         this.searchString = parameters.getString("foo");
     }

     public boolean filter(String value) {
         return value.equals(searchString);
     }
 }
 

By default, this method does nothing.

Specified by:

open in interface RichFunction

Overrides:

open in class AbstractRichFunction

Parameters:

parameters - The configuration containing the parameters attached to the contract.

Throws:

Exception - Implementations may forward exceptions, which are caught by the runtime. When the runtime catches an exception, it aborts the task and lets the fail-over logic decide whether to retry the task execution.

See Also:

Configuration

processElement

public void processElement(RowData input,
                           KeyedProcessFunction.Context ctx,
                           Collector<RowData> out)
                    throws Exception

Description copied from class: KeyedProcessFunction

Process one element from the input stream.

This function can output zero or more elements using the Collector parameter and also update internal state or set timers using the KeyedProcessFunction.Context parameter.

Specified by:

processElement in class KeyedProcessFunction<RowData,RowData,RowData>

Parameters:

input - The input value.

ctx - A KeyedProcessFunction.Context that allows querying the timestamp of the element and getting a TimerService for registering timers and querying the time. The context is only valid during the invocation of this method, do not store it.

out - The collector for returning result values.

Throws:

Exception - This method may throw exceptions. Throwing an exception will cause the operation to fail and may trigger recovery.

close

public void close()
           throws Exception

Description copied from interface: RichFunction

Tear-down method for the user code. It is called after the last call to the main working methods (e.g. map or join). For functions that are part of an iteration, this method will be invoked after each iteration superstep.

This method can be used for clean up work.

Specified by:

close in interface RichFunction

Overrides:

close in class AbstractRichFunction

Throws:

Exception - Implementations may forward exceptions, which are caught by the runtime. When the runtime catches an exception, it aborts the task and lets the fail-over logic decide whether to retry the task execution.