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sun.nio.fs

pack-priv abstract Class Cancellable

Class Inheritance

extends Object
implements Runnable

java.lang.Object
sun.nio.fs.Cancellable

All Implemented Interfaces

java.lang.Runnable

Imports

java.util.concurrent.ExecutionException, jdk.internal.misc.InnocuousThread, .Unsafe

Base implementation of a task (typically native) that polls a memory location during execution so that it may be aborted/cancelled before completion. The task is executed by invoking the runInterruptibly method defined here and cancelled by invoking Thread.interrupt.

Field Summary

Modifier and Type	Field and Description
private boolean	completed
private Throwable	exception
private final Object	lock
private final long	pollingAddress
private static final Unsafe	unsafe

Constructor Summary

Access	Constructor and Description
protected	Cancellable()

Method Summary

Modifier and Type	Method and Description
protected long	addressToPollForCancel() Returns the memory address of a 4-byte int that should be polled to detect cancellation.
pack-priv final void	cancel() "cancels" the task by writing bits into memory location that it polled by the task.
protected int	cancelValue() The value to write to the polled memory location to indicate that the task has been cancelled.
private Throwable	exception() Returns the exception thrown by the task or null if the task completed successfully.
pack-priv abstract void	implRun() The task body.
public final void	run() Implements java.lang.Runnable.run. Runs this operation.
pack-priv static void	runInterruptibly(Cancellable task) Invokes the given task in its own thread.

Inherited from java.lang.Object:: clone equals finalize getClass hashCode notify notifyAll toString wait wait wait

Field Detail

completed	back to summary
private boolean completed

exception	back to summary
private Throwable exception

lock	back to summary
private final Object lock

pollingAddress	back to summary
private final long pollingAddress

unsafe	back to summary
private static final Unsafe unsafe

Constructor Detail

Cancellable	back to summary
protected Cancellable()

Method Detail

addressToPollForCancel	back to summary
protected long addressToPollForCancel() Returns the memory address of a 4-byte int that should be polled to detect cancellation.

cancel	back to summary
pack-priv final void cancel() "cancels" the task by writing bits into memory location that it polled by the task.

cancelValue	back to summary
protected int cancelValue() The value to write to the polled memory location to indicate that the task has been cancelled. If this method is not overridden then it defaults to MAX_VALUE.

exception	back to summary
private Throwable exception() Returns the exception thrown by the task or null if the task completed successfully.

implRun	back to summary
pack-priv abstract void implRun() throws Throwable The task body. This should periodically poll the memory location to check for cancellation.

run

back to summary

public final void run()

Implements java.lang.Runnable.run.

Doc from java.lang.Runnable.run.

Runs this operation.

Annotations

@Override

runInterruptibly	back to summary
pack-priv static void runInterruptibly(Cancellable task) throws ExecutionException Invokes the given task in its own thread. If this (meaning the current) thread is interrupted then an attempt is make to cancel the background thread by writing into the memory location that it polls cooperatively.