org.jikesrvm.scheduler

Class RVMThread.GCBlockAdapter

java.lang.Object

org.jikesrvm.scheduler.RVMThread.BlockAdapter

org.jikesrvm.scheduler.RVMThread.GCBlockAdapter

Enclosing class:

RVMThread

public static class RVMThread.GCBlockAdapter
extends RVMThread.BlockAdapter

Constructor Summary

Constructors

Constructor and Description
GCBlockAdapter()

Method Summary

Modifier and Type	Method and Description
(package private) void	clearBlockRequest(RVMThread t) Clears any blocking requests for the thread.
(package private) boolean	hasBlockRequest(RVMThread t)
(package private) boolean	hasBlockRequest(RVMThread t, int token)
(package private) boolean	isBlocked(RVMThread t)
(package private) int	requestBlock(RVMThread t) Requests that the thread block, for this block adapter, at its earliest convenience.
(package private) void	setBlocked(RVMThread t, boolean value) Specifies that the thread is either blocked (value == true) or not blocked (value == false) for this block adapter.

Methods inherited from class java.lang.Object

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

Constructor Detail

GCBlockAdapter

public GCBlockAdapter()

Method Detail

isBlocked

boolean isBlocked(RVMThread t)

Specified by:

isBlocked in class RVMThread.BlockAdapter

Parameters:

t - a thread

Returns:

whether the given thread should be blocked for this block adapter. If true, the thread is guaranteed to block.

setBlocked

void setBlocked(RVMThread t,
                boolean value)

Description copied from class: RVMThread.BlockAdapter

Specifies that the thread is either blocked (value == true) or not blocked (value == false) for this block adapter. This call indicates a statement of fact by the thread itself - it's used either to acknowledge a block request (see RVMThread.BlockAdapter.hasBlockRequest(RVMThread) below) or to respond to a request to unblock.

Specified by:

setBlocked in class RVMThread.BlockAdapter

Parameters:

t - the thread

value - the new value of the status for blocking as described above

requestBlock

int requestBlock(RVMThread t)

Description copied from class: RVMThread.BlockAdapter

Requests that the thread block, for this block adapter, at its earliest convenience.

Called from RVMThread.block() and associated methods. Some block adapters allow for multiple requests to block; in that case this will return a "token" that can be passed to hasBlockRequest() to check, not only whether there is a block request, but whether that block request is still associated with a particular call to requestBlock(). This is used to prevent a suspend() call from stalling due to a concurrent resume() and second suspend(). Note that most block adapers don't care about this scenario, and will just return 0 (or some other meaningless number) here.

Specified by:

requestBlock in class RVMThread.BlockAdapter

Parameters:

t - the thread that needs to block

Returns:

a token as described above

hasBlockRequest

boolean hasBlockRequest(RVMThread t)

Specified by:

hasBlockRequest in class RVMThread.BlockAdapter

Parameters:

t - the thread

Returns:

whether the thread has a request to block for this block adapter

hasBlockRequest

boolean hasBlockRequest(RVMThread t,
                        int token)

Specified by:

hasBlockRequest in class RVMThread.BlockAdapter

Parameters:

t - the thread to check for block requests

token - a token, see RVMThread.BlockAdapter.requestBlock(RVMThread)

Returns:

whether the thread has a block request associated with the given requestBlock() call

clearBlockRequest

void clearBlockRequest(RVMThread t)

Description copied from class: RVMThread.BlockAdapter

Clears any blocking requests for the thread.

Specified by:

clearBlockRequest in class RVMThread.BlockAdapter

Parameters:

t - thread whose block requests will be cleared