org.jikesrvm.scheduler

Class RVMThread.SoftHandshakeVisitor

java.lang.Object

org.jikesrvm.scheduler.RVMThread.SoftHandshakeVisitor

Direct Known Subclasses:

CodePatchSyncRequestVisitor

Enclosing class:

RVMThread

public abstract static class RVMThread.SoftHandshakeVisitor
extends Object

Provides a skeleton implementation for use in soft handshakes.

During a soft handshake, the requesting thread waits for all mutator threads (i.e. non-gc threads) to perform a requested action.

Constructor Summary

Constructors

Constructor and Description
SoftHandshakeVisitor()

Method Summary

Modifier and Type	Method and Description
abstract boolean	checkAndSignal(RVMThread t) Sets whatever flags need to be set to signal that the given thread should perform some action when it acknowledges the soft handshake.
boolean	includeThread(RVMThread t) Checks whether to include the specified thread in the soft handshake.
void	notifyStuckInNative(RVMThread t) Called when it is determined that the thread is stuck in native.

Methods inherited from class java.lang.Object

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

Constructor Detail

SoftHandshakeVisitor

public SoftHandshakeVisitor()

Method Detail

checkAndSignal

public abstract boolean checkAndSignal(RVMThread t)

Sets whatever flags need to be set to signal that the given thread should perform some action when it acknowledges the soft handshake.

This method is only called for threads for which includeThread(RVMThread) is true.

This method is called with the thread's monitor held, but while the thread may still be running. This method is not called on mutators that have indicated that they are about to terminate.

Parameters:

t - the thread that will be processed

Returns:

false if not interested in this thread, true otherwise. Returning true will cause a soft handshake request to be put through.

notifyStuckInNative

public void notifyStuckInNative(RVMThread t)

Called when it is determined that the thread is stuck in native. While this method is being called, the thread cannot return to running Java code. As such, it is safe to perform actions "on the thread's behalf".

This implementation does nothing.

Parameters:

t - the thread that's stuck in native

includeThread

public boolean includeThread(RVMThread t)

Checks whether to include the specified thread in the soft handshake.

This method will never see any threads from the garbage collector because those are excluded from the soft handshake by design.

This implementation always returns true.

Parameters:

t - The thread to check for inclusion

Returns:

true if the thread should be included.