javax.realtime

Class ReleaseParameters<T extends ReleaseParameters<T>>

java.lang.Object

javax.realtime.ReleaseParameters<T>

All Implemented Interfaces:

Serializable, Cloneable

Direct Known Subclasses:

AperiodicParameters, PeriodicParameters

public abstract class ReleaseParameters<T extends ReleaseParameters<T>>
extends Object
implements Serializable, Cloneable

Jamaica Real-Time Specification for Java class ReleaseParameters

Release parameter object can be associated to schedulable objects by passing an instance of release parameters to the constructor of the schedulable object or by explicitly setting the release parameters of this schedulable object. A single instance of release parameters can be associated with several different schedulable objects. Changes to the instance of release parameters affect the behavior of all schedulable objects they are associated with.

Note that any changes to RelativeTime arguments of this object do not propagate to the schedulable object until the corresponding setter method of AperiodicParameters is called to notify this object about the change.

NOTE: the methods in this class are not synchronized. They cannot be used by several threads simultaneously without proper explicit synchronization.

See Also:

Serialized Form

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	ReleaseParameters() Constructor to construct release parameters with default values parameters.
protected	ReleaseParameters(RelativeTime cost, RelativeTime deadline, AsyncEventHandler overrunHandler, AsyncEventHandler missHandler) Constructor to create a new instance of ReleaseParameters.
protected	ReleaseParameters(RelativeTime cost, RelativeTime deadline, AsyncEventHandler overrunHandler, AsyncEventHandler missHandler, boolean rousable) Constructor to create a new instance of ReleaseParameters.

Method Summary

Modifier and Type	Method and Description
Object	clone() clone creates a clone of this object with the same parameters but without association to any schedulable object.
RelativeTime	getCost() getCost rturns the current value of cost
AsyncEventHandler	getCostOverrunHandler() getCostOverrunHandler returns the current cost overrun handler.
RelativeTime	getDeadline() getDeadline returns the current deadline.
AsyncEventHandler	getDeadlineMissHandler() getDeadlineMissHandler the current deadline miss handler.
QueueOverflowPolicy	getEventQueueOverflowPolicy() Gets the behavior of the arrival time queue in the event of an overflow.
boolean	isRousable() Determines whether or not a thread interrupt will cause instances of Schedulable associated with an instance of this class to be prematurely released, i.e., released before the very first release event happens.
T	setCost(RelativeTime cost) setCost sets the cost for this ReleaseParameters.
T	setCostOverrunHandler(AsyncEventHandler overrunHandler) setCostOverrunHandler sets the cost overrun handler.
T	setDeadline(RelativeTime deadline) setDeadline sets the deadline.
T	setDeadlineMissHandler(AsyncEventHandler handler) setDeadlineMissHandler sets the deadline miss handler
boolean	setIfFeasible(RelativeTime cost, RelativeTime deadline) setIfFeasible performs a feasibility analysis using the new cost and deadline parameters.
T	setRousable(boolean value) Dictates whether or not a thread interrupt will cause instances of Schedulable associated with an instance of this class to be prematurely released, i.e., released before the very first release event happens.

Methods inherited from class java.lang.Object

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

Constructor Detail

ReleaseParameters

protected ReleaseParameters()

Constructor to construct release parameters with default values parameters. Equivalent to ReleaseParemeters(null, null, null, null);

ReleaseParameters

protected ReleaseParameters(RelativeTime cost,
                            RelativeTime deadline,
                            AsyncEventHandler overrunHandler,
                            AsyncEventHandler missHandler)

Constructor to create a new instance of ReleaseParameters.

Throws:

StaticIllegalArgumentException - if cost is negative or deadline is negative or zero.

IllegalAssignmentError - when cost, deadline, overrunHandler, or missHandler cannot be stored in this.

Parameters:

cost - The CPU time required for each release. If cost monitoring is performed, this gives the maximum amount of CPU time that will be allowed for each release. In any case, this may be used by the feasibility analysis. If null, the default value will be new RelativeTime(0, 0). Note that on a system with cost monitoring, this default value will allow no execution time for the associated schedulable object.

deadline - The deadline for the completion of one release, relative to the release time of that release. If null, the default value is a new instance of RelativeTime(Long.MAX_VALUE, 999999).

overrunHandler - This handler will be invoked if the cost of one invocation exceeds the cost parameter. If null, there will be no overrunHandler.

For JamaicaVM, cost overrun checking is enabled if CpuTime.CPU_TIME_SUPPORTED is true. The accuracy of the cost enforcement can be specified in nanoseconds via the property jamaica.cost_monitoring_accuracy. The default value is 5000000, i.e., 5milliseconds.

missHandler - This handler will be invoked if the deadline of one release is missed. If null, there will be no deadline.

ReleaseParameters

protected ReleaseParameters(RelativeTime cost,
                            RelativeTime deadline,
                            AsyncEventHandler overrunHandler,
                            AsyncEventHandler missHandler,
                            boolean rousable)

Constructor to create a new instance of ReleaseParameters.

Throws:

StaticIllegalArgumentException - if cost is negative or deadline is negative or zero.

IllegalAssignmentError - when cost, deadline, overrunHandler, or missHandler cannot be stored in this. Since RTSJ 2.0

Parameters:

cost - The CPU time required for each release. If cost monitoring is performed, this gives the maximum amount of CPU time that will be allowed for each release. In any case, this may be used by the feasibility analysis. If null, the default value will be new RelativeTime(0, 0). Note that on a system with cost monitoring, this default value will allow no execution time for the associated schedulable object.

deadline - The deadline for the completion of one release, relative to the release time of that release. If null, the default value is a new instance of RelativeTime(Long.MAX_VALUE, 999999).

overrunHandler - This handler will be invoked if the cost of one invocation exceeds the cost parameter. If null, there will be no overrunHandler.

For JamaicaVM, cost overrun checking is enabled if CpuTime.CPU_TIME_SUPPORTED is true. The accuracy of the cost enforcement can be specified in nanoseconds via the property jamaica.cost_monitoring_accuracy. The default value is 5000000, i.e., 5milliseconds.

missHandler - This handler will be invoked if the deadline of one release is missed. If null, there will be no deadline.

rousable - When true, an interrupt will cause this schedulable fire immediately.

Method Detail

setIfFeasible

public boolean setIfFeasible(RelativeTime cost,
                             RelativeTime deadline)

setIfFeasible performs a feasibility analysis using the new cost and deadline parameters. If the resulting system remains feasible, the period, cost, and deadline will be set to the new values. This will change the corresponding attributes of all schedulable objects this is associated with.

Throws:

StaticIllegalArgumentException - if cost is negative or deadline is negative or zero.

Parameters:

cost - The CPU time required for each release. If cost monitoring is performed, this gives the maximum amount of CPU time that will be allowed for each release. In any case, this may be used by the feasibility analysis. If null, the default value will be new RelativeTime(0, 0). Note that on a system with cost monitoring, this default value will allow no execution time for the associated schedulable object.

deadline - The deadline for the completion of one release, relative to the release time of that release. If null, the default value is a new instance of RealtiveTime(Long.MAX_VALUE, 999999).

Returns:

true if the change was performed and the resulting system is feasible. false if the change would result in an infeasible system and was not performed.

setRousable

public T setRousable(boolean value)

Dictates whether or not a thread interrupt will cause instances of Schedulable associated with an instance of this class to be prematurely released, i.e., released before the very first release event happens.

Parameters:

value - When rousable, true and false when not.

Returns:

this

Since:

RTSJ 2.0

isRousable

public boolean isRousable()

Determines whether or not a thread interrupt will cause instances of Schedulable associated with an instance of this class to be prematurely released, i.e., released before the very first release event happens. It has no effect for periodic realtime threads, since the first event of a timing is when start is called. The default value, i.e., before any call to setRousable(boolean), is false.

Note that the rousable state has no effect on instances of RealtimeThread which have an instance of BackgroundParameters for ReleaseParameters or on ordinary event handlers, i.e., those which do not extend ActiveEvent. In the former case, there are no releases to interrupt and, in the case, the handler does not have a ActiveEventDispatcher to release it.

Returns:

true when rousable and false when not.

Since:

RTSJ 2.0

getCost

public RelativeTime getCost()

getCost rturns the current value of cost

Returns:

the current cost

getCostOverrunHandler

public AsyncEventHandler getCostOverrunHandler()

getCostOverrunHandler returns the current cost overrun handler.

Returns:

the current cost overrun handler.

getDeadline

public RelativeTime getDeadline()

getDeadline returns the current deadline.

Returns:

the current deadline.

getDeadlineMissHandler

public AsyncEventHandler getDeadlineMissHandler()

getDeadlineMissHandler the current deadline miss handler.

Returns:

the current deadline miss handler.

setCost

public T setCost(RelativeTime cost)

setCost sets the cost for this ReleaseParameters.

Throws:

StaticIllegalArgumentException - if cost is negative

Parameters:

cost - The CPU time required for each release. If cost monitoring is performed, this gives the maximum amount of CPU time that will be allowed for each release. In any case, this may be used by the feasibility analysis. If null, the default value will be new RelativeTime(0, 0). Note that on a system with cost monitoring, this default value will allow no execution time for the associated schedulable object.

Since:

RTSJ 2.0 returns itself

setCostOverrunHandler

public T setCostOverrunHandler(AsyncEventHandler overrunHandler)

setCostOverrunHandler sets the cost overrun handler. For JamaicaVM, cost overrun checking is enabled if CpuTime.CPU_TIME_SUPPORTED is true. The accuracy of the cost enforcement can be specified in nanoseconds via the property jamaica.cost_monitoring_accuracy. The default value is 5000000, i.e., 5milliseconds.

Parameters:

overrunHandler - handler to be invoked in case of an overrun situation, i.e., if the handler does not finish execution before the next invocation.

Since:

RTSJ 2.0 returns itself

setDeadline

public T setDeadline(RelativeTime deadline)

setDeadline sets the deadline.

Throws:

StaticIllegalArgumentException - if deadline is negative or zero.

Parameters:

deadline - The deadline for the completion of one release, relative to the release time of that release. If null, the default value is a new instance of RealtiveTime(Long.MAX_VALUE, 999999).

Since:

RTSJ 2.0 returns itself

setDeadlineMissHandler

public T setDeadlineMissHandler(AsyncEventHandler handler)

setDeadlineMissHandler sets the deadline miss handler

Parameters:

handler - handler to be invoked in case the deadline is missed, i.e., the execution took longer than the specified deadline.

Since:

RTSJ 2.0 returns itself

clone

public Object clone()

clone creates a clone of this object with the same parameters but without association to any schedulable object. According to RTSJ 1.0.2, the cost and deadline attributes are deep-copied, whereas the missHandler and overrunHandler attributes are only shallow-copied.

Overrides:

clone in class Object

Returns:

a new instance of ReleaseParameters with equal cost and deadline attributes and copied references of the overrunHandler and missHandler attributes.

Since:

RTSJ V1.0.1

See Also:

Cloneable

getEventQueueOverflowPolicy

public QueueOverflowPolicy getEventQueueOverflowPolicy()

Gets the behavior of the arrival time queue in the event of an overflow. Be aware that the current implementation of this method is not fully compatible with RTSJ 2.0, and the RTSJ 1.0 method AperiodicParameters.getInitialArrivalTimeQueueLength() in the subclass AperiodicParameters should be used.

Throws:

StaticUnsupportedOperationException - when used with an AperiodParameters, since that class is not yet implemented for this method.

Returns:

the behavior of the arrival time queue.

Since:

RTSJ 2.0