CheckpointableInputFormat (Flink : 2.0-SNAPSHOT API)

Type Parameters:

S - The type of input split.

T - The type of the channel state to be checkpointed / included in the snapshot.

All Known Implementing Classes:

AvroInputFormat, BinaryInputFormat, CsvInputFormat, DelimitedInputFormat, GenericCsvInputFormat, HiveTableInputFormat, RowCsvInputFormat, SerializedInputFormat, TextInputFormat
```
@PublicEvolving
public interface CheckpointableInputFormat<S extends InputSplit,T extends Serializable>
```
An interface that describes InputFormats that allow checkpointing/restoring their state.

Method Summary

All Methods Instance Methods Abstract Methods
Modifier and Type	Method	Description
`T`	`getCurrentState()`	Returns the split currently being read, along with its current state.
`void`	`reopen(S split, T state)`	Restores the state of a parallel instance reading from an `InputFormat`.

- Method Detail
  - getCurrentState
```
T getCurrentState()
           throws IOException
```
    Returns the split currently being read, along with its current state. This will be used to restore the state of the reading channel when recovering from a task failure. In the case of a simple text file, the state can correspond to the last read offset in the split.
    
    Returns:
    
    The state of the channel.
    
    Throws:
    
    IOException - Thrown if the creation of the state object failed.
  - reopen
```
void reopen(S split,
            T state)
     throws IOException
```
    Restores the state of a parallel instance reading from an InputFormat. This is necessary when recovering from a task failure. When this method is called, the input format it guaranteed to be configured.
    NOTE: The caller has to make sure that the provided split is the one to whom the state belongs.
    
    Parameters:
    
    split - The split to be opened.
    
    state - The state from which to start from. This can contain the offset, but also other data, depending on the input format.
    
    Throws:
    
    IOException