java.lang.Object
- org.apache.flink.runtime.io.network.partition.consumer.InputChannel

Direct Known Subclasses:

LocalInputChannel, RecoveredInputChannel, RemoteInputChannel
```
public abstract class InputChannel
extends Object
```
An input channel consumes a single ResultSubpartitionView.
For each channel, the consumption life cycle is as follows:

Nested Class Summary

Nested Classes
Modifier and Type	Class	Description
`static class`	`InputChannel.BufferAndAvailability`	A combination of a `Buffer` and a flag indicating availability of further buffers, and the backlog length indicating how many non-event buffers are available in the subpartitions.

Field Summary

Fields
Modifier and Type	Field	Description
`protected InputChannelInfo`	`channelInfo`	The info of the input channel to identify it globally within a task.
`protected ResultSubpartitionIndexSet`	`consumedSubpartitionIndexSet`	The indexes of the subpartitions consumed by this channel.
`protected int`	`currentBackoff`	The current backoff (in ms).
`protected int`	`initialBackoff`	The initial backoff (in ms).
`protected SingleInputGate`	`inputGate`
`protected int`	`maxBackoff`	The maximum backoff (in ms).
`protected Counter`	`numBuffersIn`
`protected Counter`	`numBytesIn`
`protected ResultPartitionID`	`partitionId`	The parent partition of the subpartitions consumed by this channel.

Constructor Summary

Constructors
Modifier	Constructor	Description
`protected`	`InputChannel(SingleInputGate inputGate, int channelIndex, ResultPartitionID partitionId, ResultSubpartitionIndexSet consumedSubpartitionIndexSet, int initialBackoff, int maxBackoff, Counter numBytesIn, Counter numBuffersIn)`

Method Summary

All Methods Instance Methods Abstract Methods Concrete Methods
Modifier and Type	Method	Description
`abstract void`	`acknowledgeAllRecordsProcessed()`	When received `EndOfData` from one channel, it need to acknowledge after this event get processed.
`protected void`	`checkError()`	Checks for an error and rethrows it if one was reported.
`void`	`checkpointStarted(CheckpointBarrier barrier)`	Called by task thread when checkpointing is started (e.g., any input channel received barrier).
`void`	`checkpointStopped(long checkpointId)`	Called by task thread on cancel/complete to clean-up temporary data.
`void`	`convertToPriorityEvent(int sequenceNumber)`
`int`	`getChannelIndex()`	Returns the index of this channel within its `SingleInputGate`.
`InputChannelInfo`	`getChannelInfo()`	Returns the info of this channel, which uniquely identifies the channel in respect to its operator instance.
`ResultSubpartitionIndexSet`	`getConsumedSubpartitionIndexSet()`
`protected int`	`getCurrentBackoff()`	Returns the current backoff in ms.
`abstract Optional<InputChannel.BufferAndAvailability>`	`getNextBuffer()`	Returns the next buffer from the consumed subpartitions or `Optional.empty()` if there is no data to return.
`ResultPartitionID`	`getPartitionId()`
`protected boolean`	`increaseBackoff()`	Increases the current backoff and returns whether the operation was successful.
`protected void`	`notifyBufferAvailable(int numAvailableBuffers)`
`protected void`	`notifyChannelNonEmpty()`	Notifies the owning `SingleInputGate` that this channel became non-empty.
`void`	`notifyPriorityEvent(int priorityBufferNumber)`
`void`	`notifyRequiredSegmentId(int subpartitionId, int segmentId)`	Notify the upstream the id of required segment that should be sent to netty connection.
`int`	`peekNextBufferSubpartitionId()`	Returns the index of the subpartition where the next buffer locates, or -1 if there is no buffer available and the subpartition to be consumed is not determined.
`protected abstract int`	`peekNextBufferSubpartitionIdInternal()`	Returns the index of the subpartition where the next buffer locates, or -1 if there is no buffer available and the subpartition to be consumed is not determined.
`abstract void`	`resumeConsumption()`	After sending a `CheckpointBarrier` of exactly-once mode, the upstream will be blocked and become unavailable.
`protected void`	`setError(Throwable cause)`	Atomically sets an error for this channel and notifies the input gate about available data to trigger querying this channel by the task thread.
`int`	`unsynchronizedGetNumberOfQueuedBuffers()`
`long`	`unsynchronizedGetSizeOfQueuedBuffers()`

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

- Field Detail
  - channelInfo
```
protected final InputChannelInfo channelInfo
```
    The info of the input channel to identify it globally within a task.
  - partitionId
```
protected final ResultPartitionID partitionId
```
    The parent partition of the subpartitions consumed by this channel.
  - consumedSubpartitionIndexSet
```
protected final ResultSubpartitionIndexSet consumedSubpartitionIndexSet
```
    The indexes of the subpartitions consumed by this channel.
  - inputGate
```
protected final SingleInputGate inputGate
```
  - initialBackoff
```
protected final int initialBackoff
```
    The initial backoff (in ms).
  - maxBackoff
```
protected final int maxBackoff
```
    The maximum backoff (in ms).
  - numBytesIn
```
protected final Counter numBytesIn
```
  - numBuffersIn
```
protected final Counter numBuffersIn
```
  - currentBackoff
```
protected int currentBackoff
```
    The current backoff (in ms).
- Constructor Detail
  - InputChannel
```
protected InputChannel(SingleInputGate inputGate,
                       int channelIndex,
                       ResultPartitionID partitionId,
                       ResultSubpartitionIndexSet consumedSubpartitionIndexSet,
                       int initialBackoff,
                       int maxBackoff,
                       Counter numBytesIn,
                       Counter numBuffersIn)
```
- Method Detail
  - getChannelIndex
```
public int getChannelIndex()
```
    Returns the index of this channel within its SingleInputGate.
  - getChannelInfo
```
public InputChannelInfo getChannelInfo()
```
    Returns the info of this channel, which uniquely identifies the channel in respect to its operator instance.
  - getPartitionId
```
public ResultPartitionID getPartitionId()
```
  - getConsumedSubpartitionIndexSet
```
public ResultSubpartitionIndexSet getConsumedSubpartitionIndexSet()
```
  - resumeConsumption
```
public abstract void resumeConsumption()
                                throws IOException
```
    After sending a CheckpointBarrier of exactly-once mode, the upstream will be blocked and become unavailable. This method tries to unblock the corresponding upstream and resume data consumption.
    
    Throws:
    
    IOException
  - acknowledgeAllRecordsProcessed
```
public abstract void acknowledgeAllRecordsProcessed()
                                             throws IOException
```
    When received EndOfData from one channel, it need to acknowledge after this event get processed.
    
    Throws:
    
    IOException
  - notifyChannelNonEmpty
```
protected void notifyChannelNonEmpty()
```
    Notifies the owning SingleInputGate that this channel became non-empty.
    This is guaranteed to be called only when a Buffer was added to a previously empty input channel. The notion of empty is atomically consistent with the flag InputChannel.BufferAndAvailability.moreAvailable() when polling the next buffer from this channel.
    Note: When the input channel observes an exception, this method is called regardless of whether the channel was empty before. That ensures that the parent InputGate will always be notified about the exception.
  - notifyPriorityEvent
```
public void notifyPriorityEvent(int priorityBufferNumber)
```
  - notifyBufferAvailable
```
protected void notifyBufferAvailable(int numAvailableBuffers)
                              throws IOException
```
    Throws:
    
    IOException
  - peekNextBufferSubpartitionId
```
public int peekNextBufferSubpartitionId()
                                 throws IOException
```
    Returns the index of the subpartition where the next buffer locates, or -1 if there is no buffer available and the subpartition to be consumed is not determined.
    
    Throws:
    
    IOException
  - peekNextBufferSubpartitionIdInternal
```
protected abstract int peekNextBufferSubpartitionIdInternal()
                                                     throws IOException
```
    Returns the index of the subpartition where the next buffer locates, or -1 if there is no buffer available and the subpartition to be consumed is not determined.
    
    Throws:
    
    IOException
  - getNextBuffer
```
public abstract Optional<InputChannel.BufferAndAvailability> getNextBuffer()
                                                                    throws IOException,
                                                                           InterruptedException
```
    Returns the next buffer from the consumed subpartitions or Optional.empty() if there is no data to return.
    
    Throws:
    
    IOException
    
    InterruptedException
  - checkpointStarted
```
public void checkpointStarted(CheckpointBarrier barrier)
                       throws CheckpointException
```
    Called by task thread when checkpointing is started (e.g., any input channel received barrier).
    
    Throws:
    
    CheckpointException
  - checkpointStopped
```
public void checkpointStopped(long checkpointId)
```
    Called by task thread on cancel/complete to clean-up temporary data.
  - convertToPriorityEvent
```
public void convertToPriorityEvent(int sequenceNumber)
                            throws IOException
```
    Throws:
    
    IOException
  - checkError
```
protected void checkError()
                   throws IOException
```
    Checks for an error and rethrows it if one was reported.
    Note: Any PartitionException instances should not be transformed and make sure they are always visible in task failure cause.
    
    Throws:
    
    IOException
  - setError
```
protected void setError(Throwable cause)
```
    Atomically sets an error for this channel and notifies the input gate about available data to trigger querying this channel by the task thread.
  - getCurrentBackoff
```
protected int getCurrentBackoff()
```
    Returns the current backoff in ms.
  - increaseBackoff
```
protected boolean increaseBackoff()
```
    Increases the current backoff and returns whether the operation was successful.
    
    Returns:
    
    true, iff the operation was successful. Otherwise, false.
  - unsynchronizedGetNumberOfQueuedBuffers
```
public int unsynchronizedGetNumberOfQueuedBuffers()
```
  - unsynchronizedGetSizeOfQueuedBuffers
```
public long unsynchronizedGetSizeOfQueuedBuffers()
```
  - notifyRequiredSegmentId
```
public void notifyRequiredSegmentId(int subpartitionId,
                                    int segmentId)
                             throws IOException
```
    Notify the upstream the id of required segment that should be sent to netty connection.
    
    Parameters:
    
    subpartitionId - The id of the corresponding subpartition.
    
    segmentId - The id of required segment.
    
    Throws:
    
    IOException

Class InputChannel

Nested Class Summary

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

channelInfo

partitionId

consumedSubpartitionIndexSet

inputGate

initialBackoff

maxBackoff

numBytesIn

numBuffersIn

currentBackoff

Constructor Detail

InputChannel

Method Detail

getChannelIndex

getChannelInfo

getPartitionId

getConsumedSubpartitionIndexSet

resumeConsumption

acknowledgeAllRecordsProcessed

notifyChannelNonEmpty

notifyPriorityEvent

notifyBufferAvailable

peekNextBufferSubpartitionId

peekNextBufferSubpartitionIdInternal

getNextBuffer

checkpointStarted

checkpointStopped

convertToPriorityEvent

checkError

setError

getCurrentBackoff

increaseBackoff

unsynchronizedGetNumberOfQueuedBuffers

unsynchronizedGetSizeOfQueuedBuffers

notifyRequiredSegmentId