java.lang.Object
- org.apache.cassandra.service.reads.ReadCallback<E,P>

All Implemented Interfaces:: RequestCallback<ReadResponse>

public class ReadCallback<E extends Endpoints<E>,P extends ReplicaPlan.ForRead<E,P>>
extends java.lang.Object
implements RequestCallback<ReadResponse>

Field Summary

Fields
Modifier and Type Field Description

protected static org.slf4j.Logger logger

ResponseResolver<E,P> resolver

Constructor Summary

Constructors
Constructor	Description
`ReadCallback(ResponseResolver<E,P> resolver, ReadCommand command, ReplicaPlan.Shared<E,P> replicaPlan, Dispatcher.RequestTime requestTime)`

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`boolean`	`await(long commandTimeout, java.util.concurrent.TimeUnit unit)`
`void`	`awaitResults()`
`boolean`	`awaitUntil(long deadline)`	In case of speculation, we want to time out the request immediately if we have _also_ hit a deadline.
`int`	`blockFor()`
`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.
`void`	`onFailure(InetAddressAndPort from, RequestFailureReason failureReason)`	Called when there is an exception on the remote node or timeout happens
`void`	`onResponse(Message<ReadResponse> message)`
`protected P`	`replicaPlan()`
`void`	`response(ReadResponse result)`
`boolean`	`trackLatencyForSnitch()`

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

- Field Detail
  - logger
```
protected static final org.slf4j.Logger logger
```
  - resolver
```
public final ResponseResolver<E extends Endpoints<E>,P extends ReplicaPlan.ForRead<E,P>> resolver
```
- Constructor Detail
  - ReadCallback
```
public ReadCallback(ResponseResolver<E,P> resolver,
                    ReadCommand command,
                    ReplicaPlan.Shared<E,P> replicaPlan,
                    Dispatcher.RequestTime requestTime)
```
- Method Detail
  - replicaPlan
```
protected P replicaPlan()
```
  - await
```
public boolean await(long commandTimeout,
                     java.util.concurrent.TimeUnit unit)
```
  - awaitUntil
```
public boolean awaitUntil(long deadline)
```
    In case of speculation, we want to time out the request immediately if we have _also_ hit a deadline. For example, we have a read timeout of 10s, 99% latency of 5 seconds, and time base is QUEUE: * Request has spent 3 seconds in the queue. Here, we will wait for 2 seconds and try to speculate * Request has spent 10 seconds in the queue. Here, we will wait for 0 seconds and try to speculate If the time base is REQUEST: * Request has spent 10 seconds in the queue. Here, we will only wait 2 seconds and then try to speculate We should _not_ speculate in all these cases, since by that time we are already past request deadline.
  - awaitResults
```
public void awaitResults()
                  throws ReadFailureException,
                         ReadTimeoutException
```
    Throws:
    
    ReadFailureException
    
    ReadTimeoutException
  - blockFor
```
public int blockFor()
```
  - onResponse
```
public void onResponse(Message<ReadResponse> message)
```
    Specified by:
    
    onResponse in interface RequestCallback<E extends Endpoints<E>>
    
    Parameters:
    
    message - response received.
  - response
```
public void response(ReadResponse result)
```
  - trackLatencyForSnitch
```
public boolean trackLatencyForSnitch()
```
    Specified by:
    
    trackLatencyForSnitch in interface RequestCallback<E extends Endpoints<E>>
    
    Returns:
    
    true if this callback is on the read path and its latency should be given as input to the dynamic snitch.
  - onFailure
```
public void onFailure(InetAddressAndPort from,
                      RequestFailureReason failureReason)
```
    Description copied from interface: RequestCallback
    
    Called when there is an exception on the remote node or timeout happens
    
    Specified by:
    
    onFailure in interface RequestCallback<E extends Endpoints<E>>
  - invokeOnFailure
```
public boolean invokeOnFailure()
```
    Description copied from interface: RequestCallback
    
    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
    
    Specified by:
    
    invokeOnFailure in interface RequestCallback<E extends Endpoints<E>>
    
    Returns:
    
    true if the callback should be invoked on failure

Modifier and Type	Field	Description
`protected static org.slf4j.Logger`	`logger`
`ResponseResolver<E,P>`	`resolver`

Class ReadCallback<E extends Endpoints<E>,​P extends ReplicaPlan.ForRead<E,​P>>

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

logger

resolver

Constructor Detail

ReadCallback

Method Detail

replicaPlan

await

awaitUntil

awaitResults

blockFor

onResponse

response

trackLatencyForSnitch

onFailure

invokeOnFailure

Class ReadCallback<E extends Endpoints<E>,P extends ReplicaPlan.ForRead<E,P>>