javax.realtime

Class MonitorControl

java.lang.Object

javax.realtime.MonitorControl

Direct Known Subclasses:

PriorityCeilingEmulation, PriorityInheritance

public abstract class MonitorControl
extends java.lang.Object

Abstract superclass for all monitor control policies.

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	MonitorControl() Invoked from subclass constructors.

Method Summary

Modifier and Type	Method and Description
static MonitorControl	getMonitorControl() Gets the current default monitor control policy.
static MonitorControl	getMonitorControl(java.lang.Object monitor) Gets the monitor control policy of the given instance of Object.
static MonitorControl	setMonitorControl(MonitorControl policy) Sets the default monitor control policy.
static MonitorControl	setMonitorControl(java.lang.Object obj, MonitorControl policy) Immediately sets policy as the monitor control policy for obj.

Methods inherited from class java.lang.Object

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

Constructor Detail

MonitorControl

protected MonitorControl()

Invoked from subclass constructors.

Method Detail

getMonitorControl

public static MonitorControl getMonitorControl(java.lang.Object monitor)

Gets the monitor control policy of the given instance of Object.

Parameters:

monitor - The object being queried.

Returns:

the monitor control policy of the monitor parameter.

Throws:

StaticIllegalArgumentException - when monitor is null.

getMonitorControl

public static MonitorControl getMonitorControl()

Gets the current default monitor control policy.

Returns:

the default monitor control policy object.

setMonitorControl

public static MonitorControl setMonitorControl(MonitorControl policy)
                                        throws StaticIllegalArgumentException,
                                               StaticUnsupportedOperationException,
                                               StaticIllegalStateException

Sets the default monitor control policy. This policy does not affect the monitor control policy of any already created object, it will, however, govern any object whose creation happens after the method completes, until either

1. a new ``per-object'' policy is set for that object, thereby altering the monitor control policy for a single object without changing the default policy, or
2. a new default policy is set.

Like the per-object method (see setMonitorControl(Object, MonitorControl), the setting of the default monitor control policy occurs immediately, but may not be visible on all processors of a multicore system simultaneously.

Parameters:

policy - The new monitor control policy. When null, the default MonitorControl policy is not changed.

Returns:

the default MonitorControl policy in effect on completion.

Throws:

StaticSecurityException - when the caller is not permitted to alter the default monitor control policy.

StaticIllegalArgumentException - when policy is not in immortal memory.

StaticUnsupportedOperationException - when policy is not a supported monitor control policy.

StaticIllegalStateException

Since:

RTSJ 1.0.1 The return type is changed from void to MonitorControl.

setMonitorControl

public static MonitorControl setMonitorControl(java.lang.Object obj,
                                               MonitorControl policy)

Immediately sets policy as the monitor control policy for obj.

Monitor control policy changes on a monitor that is actively contended may lead to queued or enqueuing tasks following either the old or new policy in an unpredictable fashion. Tasks enqueued after the monitor is released after a policy change will follow the new policy.

A thread or schedulable that is queued for the lock associated with obj, or is in obj's wait set, is not rechecked (e.g., for a CeilingViolationException) under policy, either as part of the execution of setMonitorControl or when it is awakened to (re)acquire the lock.

The thread or schedulable invoking setMonitorControl must already hold the lock on obj.

Parameters:

obj - The object that will be governed by the new policy.

policy - The new policy for the object. When null nothing will happen.

Returns:

the current MonitorControl policy for obj, which will be replaced.

Throws:

StaticIllegalArgumentException - when obj is null or policy is not in immortal memory.

StaticUnsupportedOperationException - when policy is not a supported monitor control policy.

java.lang.IllegalMonitorStateException - when the caller does not hold a lock on obj.

Since:

RTSJ 1.0.1 The return type has been changed from void to MonitorControl.