org.jikesrvm.scheduler

Class Latch

java.lang.Object

org.jikesrvm.scheduler.Latch

public class Latch
extends Object

An implementation of a latch using the HeavyCondLock in "nice" mode. This essentially gives you park/unpark functionality. It can also be used like the Win32-style AutoResetEvent or ManualResetEvent.

Park/unpark example: use open() to unpark and waitAndClose() to park.

AutoResetEvent example: use open() to set, close() to reset, and waitAndClose() to wait.

ManualResetEvent example: use open() to set, close() to reset, and wait() to wait.

Field Summary

Fields

Modifier and Type	Field and Description
private boolean	open
private Monitor	schedLock

Constructor Summary

Constructors

Constructor and Description
Latch(boolean open) Create a new latch, with the given open/closed state.

Method Summary

Modifier and Type	Method and Description
void	closeWithHandshake() Close the latch, causing future calls to wait() or waitAndClose() to block.
void	openNoHandshake() Like open(), but does it without letting the system know that we could potentially block.
void	openWithHandshake() Open the latch and let all of the thread(s) waiting on it through.
void	waitAndCloseWithHandshake() Wait for the latch to become open, and then close it and return.
void	waitWithHandshake() Wait for the latch to become open.

Methods inherited from class java.lang.Object

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

Field Detail

schedLock

private final Monitor schedLock

open

private boolean open

Constructor Detail

Latch

public Latch(boolean open)

Create a new latch, with the given open/closed state.

Parameters:

open - whether the latch is open or closed at the beginning

Method Detail

openWithHandshake

public void openWithHandshake()

Open the latch and let all of the thread(s) waiting on it through. But - if any of the threads is using waitAndClose(), then as soon as that thread awakes further threads will be blocked.

openNoHandshake

public void openNoHandshake()

Like open(), but does it without letting the system know that we could potentially block. This is faster, and better for use in interrupt handlers.

closeWithHandshake

public void closeWithHandshake()

Close the latch, causing future calls to wait() or waitAndClose() to block.

waitWithHandshake

public void waitWithHandshake()

Wait for the latch to become open. If it is already open, don't wait at all.

waitAndCloseWithHandshake

public void waitAndCloseWithHandshake()

Wait for the latch to become open, and then close it and return. If the latch is already open, don't wait at all, just close it immediately and return.