MutableState (ordered 2.74.0 API)

All Superinterfaces:

java.io.Serializable
```
public interface MutableState<EventT,ResultT>
extends java.io.Serializable
```
Mutable state mutates when events apply to it. It is stored in a Beam state.

Method Summary

All Methods Instance Methods Abstract Methods
Modifier and Type	Method	Description
`void`	`mutate(EventT event)`	The interface assumes that events will mutate the state without the possibility of throwing an error.
`ResultT`	`produceResult()`	This method is called after each state mutation.

- Method Detail
  - mutate
```
void mutate(EventT event)
     throws java.lang.Exception
```
    The interface assumes that events will mutate the state without the possibility of throwing an error.
    
    Parameters:
    
    event - to be processed
    
    Throws:
    
    java.lang.Exception - if a checked exception is thrown, the event will be output into OrderedEventProcessorResult.unprocessedEvents() with
  - produceResult
```
ResultT produceResult()
```
    This method is called after each state mutation.
    
    Returns:
    
    Result of the processing. Can be null if nothing needs to be output after this mutation.