PatternProcessFunction (Flink : Libraries : CEP 2.1.0 API)

java.lang.Object
- org.apache.flink.api.common.functions.AbstractRichFunction
- - org.apache.flink.cep.functions.PatternProcessFunction<IN,OUT>

Type Parameters:

IN - type of incoming elements

OUT - type of produced elements based on found matches

All Implemented Interfaces:

Serializable, org.apache.flink.api.common.functions.Function, org.apache.flink.api.common.functions.RichFunction

Direct Known Subclasses:

PatternFlatSelectAdapter, PatternSelectAdapter
```
@PublicEvolving
public abstract class PatternProcessFunction<IN,OUT>
extends org.apache.flink.api.common.functions.AbstractRichFunction
```
It is called with a map of detected events which are identified by their names. The names are defined by the Pattern specifying the sought-after pattern. This is the preferred way to process found matches.
```
 PatternStream<IN> pattern = ...

 DataStream<OUT> result = pattern.process(new MyPatternProcessFunction());
 
```
See Also:

Serialized Form

Nested Class Summary

Nested Classes
Modifier and Type	Class	Description
`static interface`	`PatternProcessFunction.Context`	Gives access to time related characteristics as well as enables emitting elements to side outputs.

Constructor Summary

Constructors
Constructor Description

PatternProcessFunction()

Method Summary

All Methods Instance Methods Abstract Methods
Modifier and Type	Method	Description
`abstract void`	`processMatch(Map<String,List<IN>> match, PatternProcessFunction.Context ctx, org.apache.flink.util.Collector<OUT> out)`	Generates resulting elements given a map of detected pattern events.

Methods inherited from class org.apache.flink.api.common.functions.AbstractRichFunction
close, getIterationRuntimeContext, getRuntimeContext, open, setRuntimeContext

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Constructor Detail
  - PatternProcessFunction
```
public PatternProcessFunction()
```
- Method Detail
  - processMatch
```
public abstract void processMatch(Map<String,List<IN>> match,
                                  PatternProcessFunction.Context ctx,
                                  org.apache.flink.util.Collector<OUT> out)
                           throws Exception
```
    Generates resulting elements given a map of detected pattern events. The events are identified by their specified names.
    TimeContext.timestamp() in this case returns the time of the last element that was assigned to the match, resulting in this partial match being finished.
    
    Parameters:
    
    match - map containing the found pattern. Events are identified by their names.
    
    ctx - enables access to time features and emitting results through side outputs
    
    out - Collector used to output the generated elements
    
    Throws:
    
    Exception - This method may throw exceptions. Throwing an exception will cause the operation to fail and may trigger recovery.