com.oracle.svm.core.locks

Class VMCondition

java.lang.Object

com.oracle.svm.core.locks.VMCondition

public class VMCondition
extends Object

A condition that has minimal requirements on Java code. The implementation does not perform memory allocation, exception unwinding, or other complicated operations. This allows it to be used in early startup and shutdown phases of the VM, as well as to coordinate garbage collection. It is not possible to allocate new VM conditions at run time. All VM conditions must be allocated during image generation. They are initialized during startup of the VM, i.e., every VM condition consumes resources and contributes to VM startup time.

Field Summary

Fields

Modifier and Type	Field and Description
protected VMMutex	mutex

Constructor Summary

Constructors

Constructor and Description
VMCondition(VMMutex mutex)

Method Summary

Modifier and Type	Method and Description
void	block() Waits until the condition variable gets signaled.
long	block(long nanoseconds) Waits until the condition variable gets signaled or the given number of nanoseconds has elapsed.
void	blockNoTransition() Like VMCondition.block(), but without a thread status transition.
long	blockNoTransition(long nanoseconds) Like VMCondition.blockNoTransition() but with a timeout (see VMCondition.block(long)).
void	blockNoTransitionUnspecifiedOwner() Like VMCondition.blockNoTransition(), but an unspecified lock owner is used.
void	broadcast() Wakes up all threads that are waiting on this condition.
VMMutex	getMutex()
void	signal() Wakes up a single thread that is waiting on this condition.

Methods inherited from class java.lang.Object

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

Field Detail

mutex

protected final VMMutex mutex

Constructor Detail

VMCondition

public VMCondition(VMMutex mutex)

Method Detail

getMutex

public VMMutex getMutex()

block

public void block()

Waits until the condition variable gets signaled.

blockNoTransition

public void blockNoTransition()

Like VMCondition.block(), but without a thread status transition. This method can only be called from uninterruptible code that did an explicit to-native transition before, as blocking while still in Java-mode could result in a deadlock.

block

public long block(long nanoseconds)

Waits until the condition variable gets signaled or the given number of nanoseconds has elapsed. Returns any nanoseconds remaining if it returned early.

blockNoTransition

public long blockNoTransition(long nanoseconds)

Like VMCondition.blockNoTransition() but with a timeout (see VMCondition.block(long)).

blockNoTransitionUnspecifiedOwner

public void blockNoTransitionUnspecifiedOwner()

Like VMCondition.blockNoTransition(), but an unspecified lock owner is used. Only use this method in places where CurrentIsolate.getCurrentThread() can return null.

signal

public void signal()

Wakes up a single thread that is waiting on this condition.

broadcast

public void broadcast()

Wakes up all threads that are waiting on this condition.