RemoteStorageScanner (Flink : Runtime 2.0-preview1 API)

java.lang.Object
- org.apache.flink.runtime.io.network.partition.hybrid.tiered.tier.remote.RemoteStorageScanner

All Implemented Interfaces:

Runnable
```
public class RemoteStorageScanner
extends Object
implements Runnable
```
The RemoteStorageScanner is introduced to notify asynchronously for file reading on remote storage. Asynchronous notifications will prevent RemoteTierConsumerAgent from repeatedly attempting to read remote files and reduce CPU consumption.
It will be invoked by RemoteTierConsumerAgent to watch the required segments and scan the existence status of the segments. If the segment file is found, it will notify the availability of segment file.

Constructor Summary

Constructors
Constructor Description

RemoteStorageScanner(String baseRemoteStoragePath)

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`void`	`close()`	Close the executor.
`void`	`registerAvailabilityAndPriorityNotifier(BiConsumer<TieredStoragePartitionId,TieredStorageSubpartitionId> availabilityNotifier)`
`void`	`run()`	Iterate the watched segment ids and check related file status.
`void`	`start()`	Start the executor.
`void`	`watchSegment(TieredStoragePartitionId partitionId, TieredStorageSubpartitionId subpartitionId, int segmentId)`	Watch the segment for a specific subpartition in the `RemoteStorageScanner`.

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

- Constructor Detail
  - RemoteStorageScanner
```
public RemoteStorageScanner(String baseRemoteStoragePath)
```
- Method Detail
  - start
```
public void start()
```
    Start the executor.
  - watchSegment
```
public void watchSegment(TieredStoragePartitionId partitionId,
                         TieredStorageSubpartitionId subpartitionId,
                         int segmentId)
```
    Watch the segment for a specific subpartition in the RemoteStorageScanner.
    If a segment with a larger or equal id already exists, the current segment won't be watched.
    If a segment with a smaller segment id is still being watched, the current segment will replace it because the smaller segment should have been consumed. This method ensures that only one segment file can be watched for each subpartition.
    
    Parameters:
    
    partitionId - is the id of partition.
    
    subpartitionId - is the id of subpartition.
    
    segmentId - is the id of segment.
  - close
```
public void close()
```
    Close the executor.
  - run
```
public void run()
```
    Iterate the watched segment ids and check related file status.
    
    Specified by:
    
    run in interface Runnable
  - registerAvailabilityAndPriorityNotifier
```
public void registerAvailabilityAndPriorityNotifier(BiConsumer<TieredStoragePartitionId,TieredStorageSubpartitionId> availabilityNotifier)
```