ExternalSystemDataReader (Flink : 2.0-SNAPSHOT API)

Type Parameters:

T - Type of the consuming record

All Superinterfaces:

AutoCloseable
```
@Experimental
public interface ExternalSystemDataReader<T>
extends AutoCloseable
```
A data reader for consuming records from an external system.

- Method Summary
  
  All Methods Instance Methods Abstract Methods
  Modifier and Type Method Description
  
  List<T> poll(Duration timeout)
  Poll a batch of records from external system.
  - Methods inherited from interface java.lang.AutoCloseable
    close

- Method Detail
  - poll
```
List<T> poll(Duration timeout)
```
    Poll a batch of records from external system.
    Test cases will keep invoking this method until expected records have been polled, so it's not necessary to fetch all records in one poll, but records should not be duplicated across multiple invocations.
    
    Parameters:
    
    timeout - The maximum time to block