StateSnapshotTransformer (Flink : Runtime 2.0-preview1 API)

Type Parameters:

T - type of state

All Known Subinterfaces:

StateSnapshotTransformer.CollectionStateSnapshotTransformer<T>

All Known Implementing Classes:

StateSnapshotTransformers.ListStateSnapshotTransformer, StateSnapshotTransformers.MapStateSnapshotTransformer

Functional Interface:

This is a functional interface and can therefore be used as the assignment target for a lambda expression or method reference.
```
@FunctionalInterface
@NotThreadSafe
public interface StateSnapshotTransformer<T>
```
Transformer of state values which are included or skipped in the snapshot.
This transformer can be applied to state values to decide which entries should be included into the snapshot. The included entries can be optionally modified before.
Unless specified differently, the transformer should be applied per entry for collection types of state, like list or map.

Nested Class Summary

Nested Classes
Modifier and Type	Interface	Description
`static interface`	`StateSnapshotTransformer.CollectionStateSnapshotTransformer<T>`	Collection state specific transformer which says how to transform entries of the collection.
`static interface`	`StateSnapshotTransformer.StateSnapshotTransformFactory<T>`	This factory creates state transformers depending on the form of values to transform.

Method Summary

All Methods Instance Methods Abstract Methods
Modifier and Type	Method	Description
`T`	`filterOrTransform(T value)`	Transform or filter out state values which are included or skipped in the snapshot.

- Method Detail
  - filterOrTransform
```
@Nullable
T filterOrTransform(@Nullable
                    T value)
```
    Transform or filter out state values which are included or skipped in the snapshot.
    
    Parameters:
    
    value - non-serialized form of value
    
    Returns:
    
    value to snapshot or null which means the entry is not included