RequestCallback (apache-cassandra API)

All Known Subinterfaces:

RequestCallbackWithFailure<T>

All Known Implementing Classes:

AbstractPaxosCallback, AbstractWriteResponseHandler, AsyncOneResponse, BatchlogResponseHandler, BlockingPartitionRepair, DatacenterSyncWriteResponseHandler, DatacenterWriteResponseHandler, FailureRecordingCallback, PaxosCleanupComplete, PaxosCleanupSession, PaxosCommit, PaxosFinishPrepareCleanup, PaxosPrepare, PaxosPrepareRefresh, PaxosPropose, PaxosRequestCallback, PaxosStartPrepareCleanup, PrepareCallback, ProposeCallback, ReadCallback, TruncateResponseHandler, WriteResponseHandler
```
public interface RequestCallback<T>
```
implementors of RequestCallback need to make sure that any public methods are threadsafe with respect to onResponse(org.apache.cassandra.net.Message<T>) being called from the message service. In particular, if any shared state is referenced, making response alone synchronized will not suffice.

Method Summary

All Methods Instance Methods Abstract Methods Default Methods
Modifier and Type	Method	Description
`default boolean`	`invokeOnFailure()`	Returns true if the callback handles failure reporting - in which case the remove host will be asked to report failures to us in the event of a problem processing the request.
`default void`	`onFailure(InetAddressAndPort from, RequestFailureReason failureReason)`	Called when there is an exception on the remote node or timeout happens
`void`	`onResponse(Message<T> msg)`
`default boolean`	`trackLatencyForSnitch()`

- Method Detail
  - onResponse
```
void onResponse(Message<T> msg)
```
    Parameters:
    
    msg - response received.
  - onFailure
```
default void onFailure(InetAddressAndPort from,
                       RequestFailureReason failureReason)
```
    Called when there is an exception on the remote node or timeout happens
  - invokeOnFailure
```
default boolean invokeOnFailure()
```
    Returns true if the callback handles failure reporting - in which case the remove host will be asked to report failures to us in the event of a problem processing the request. TODO: this is an error prone method, and we should be handling failures everywhere so we should probably just start doing that, and remove this method
    
    Returns:
    
    true if the callback should be invoked on failure
  - trackLatencyForSnitch
```
default boolean trackLatencyForSnitch()
```
    Returns:
    
    true if this callback is on the read path and its latency should be given as input to the dynamic snitch.