org.apache.flink.runtime.io.async

Class AbstractAsyncIOCallable<V,D extends Closeable>

java.lang.Object

org.apache.flink.runtime.io.async.AbstractAsyncIOCallable<V,D>

Type Parameters:

V - return type of the asynchronous call

D - type of the IO handle

All Implemented Interfaces:

Callable<V>, AsyncDoneCallback, AsyncStoppable, StoppableCallbackCallable<V>

Direct Known Subclasses:

AbstractAsyncSnapshotIOCallable

public abstract class AbstractAsyncIOCallable<V,D extends Closeable>
extends Object
implements StoppableCallbackCallable<V>

The abstract class encapsulates the lifecycle and execution strategy for asynchronous IO operations

Constructor Summary

Constructors

Constructor and Description
AbstractAsyncIOCallable()

Method Summary

Methods

Modifier and Type	Method and Description
V	call() This method implements the strategy for the actual IO operation: 1) Open the IO handle 2) Perform IO operation 3) Close IO handle
void	done(boolean canceled) Optional callback that subclasses can implement.
protected D	getIoHandle() Returns the IO handle.
IOException	getStopException() Returns Exception that might happen on stop.
boolean	isStopped() Check if the IO operation is stopped
protected abstract D	openIOHandle() Open the IO Handle (e.g.
protected abstract V	performOperation() Implements the actual IO operation on the opened IO handle.
void	stop() Stops the I/O operation by closing the I/O handle.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

AbstractAsyncIOCallable

public AbstractAsyncIOCallable()

Method Detail

call

public V call()
       throws Exception

This method implements the strategy for the actual IO operation: 1) Open the IO handle 2) Perform IO operation 3) Close IO handle

Specified by:

call in interface Callable<V>

Returns:

Result of the IO operation, e.g. a deserialized object.

Throws:

Exception - exception that happened during the call.

openIOHandle

protected abstract D openIOHandle()
                                             throws Exception

Open the IO Handle (e.g. a stream) on which the operation will be performed.

Returns:

the opened IO handle that implements #Closeable

Throws:

Exception

performOperation

protected abstract V performOperation()
                               throws Exception

Implements the actual IO operation on the opened IO handle.

Returns:

Result of the IO operation

Throws:

Exception

stop

public void stop()

Stops the I/O operation by closing the I/O handle. If an exception is thrown on close, it can be accessed via #getStopException().

Specified by:

stop in interface AsyncStoppable

getIoHandle

protected D getIoHandle()

Returns the IO handle.

Returns:

the IO handle

done

public void done(boolean canceled)

Optional callback that subclasses can implement. This is called when the callable method completed, e.g. because it finished or was stopped.

Specified by:

done in interface AsyncDoneCallback

Parameters:

canceled - true if the callback is done, but was canceled

isStopped

public boolean isStopped()

Check if the IO operation is stopped

Specified by:

isStopped in interface AsyncStoppable

Returns:

true if stop() was called

getStopException

public IOException getStopException()

Returns Exception that might happen on stop.

Specified by:

getStopException in interface AsyncStoppable

Returns:

Potential Exception that happened open stopping.