jdk.management.resource

Class ThrottledMeter

java.lang.Object

jdk.management.resource.SimpleMeter

jdk.management.resource.NotifyingMeter

jdk.management.resource.ThrottledMeter

All Implemented Interfaces:

ResourceMeter, ResourceRequest

public class ThrottledMeter
extends NotifyingMeter

A ThrottledMeter with bandwidth limit, an approver callback for requests and allocates from an optional parent. The rate is limited by the throttle limit and is settable at any time. The rate-per-second is the amount that can be approved each second. An amount not used in each second is accumulated up to a maximum of one seconds.

Since:

8u40

Method Summary

Modifier and Type	Method and Description
static ThrottledMeter	create(ResourceType type, long ratePerSec, ResourceApprover approver) Create a new meter with a throttle rate and approver.
static ThrottledMeter	create(ResourceType type, long ratePerSec, ResourceRequest parent, ResourceApprover approver) Create a new meter with a throttle rate, parent and approver.
static ThrottledMeter	create(ResourceType type, ResourceRequest parent, ResourceApprover approver) Create a new meter with unlimited rate, parent and approver.
long	getCurrentRate() Returns an estimate of the current rate in amount per second.
long	getRatePerSec() Returns the current throttle rate per second.
long	setRatePerSec(long ratePerSec) Sets the throttle rate per second.
String	toString() Returns a string representation of the meter.
long	validate(long previous, long amount, ResourceId id) Validates the amount.

Methods inherited from class jdk.management.resource.NotifyingMeter

create, getApprover, getGranularity, setGranularity

Methods inherited from class jdk.management.resource.SimpleMeter

create, create, equals, getAllocated, getParent, getType, getValue, hashCode, request

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Method Detail

create

public static ThrottledMeter create(ResourceType type,
                                    long ratePerSec,
                                    ResourceApprover approver)

Create a new meter with a throttle rate and approver.

Parameters:

type - the ResourceType

ratePerSec - the rate allowed for Throttling; bytes-per sec; must be greater than zero

approver - the ResourceApprover to be notified; may be null

Returns:

a new ThrottledMeter

Throws:

IllegalArgumentException - if ratePerSec is less than or equal to zero

create

public static ThrottledMeter create(ResourceType type,
                                    ResourceRequest parent,
                                    ResourceApprover approver)

Create a new meter with unlimited rate, parent and approver.

Parameters:

type - the ResourceType

parent - a ResourceRequest to request from; may be null

approver - the ResourceApprover to be notified; may be null

Returns:

a new ThrottledMeter

Throws:

IllegalArgumentException - if ratePerSec is less than or equal to zero

create

public static ThrottledMeter create(ResourceType type,
                                    long ratePerSec,
                                    ResourceRequest parent,
                                    ResourceApprover approver)

Create a new meter with a throttle rate, parent and approver.

Parameters:

type - the ResourceType

ratePerSec - the rate allowed for throttling; bytes-per sec; must be greater than zero

parent - a ResourceRequest to request from; may be null

approver - the ResourceApprover to be notified; may be null

Returns:

a new ThrottledMeter

Throws:

IllegalArgumentException - if ratePerSec is less than or equal to zero

validate

public long validate(long previous,
                     long amount,
                     ResourceId id)

Validates the amount. If returning an amount, just return it. Throttling is achieved by an algorithm similar to the token bucket. An allowance is maintained of the amount than can be immediately fulfilled to satisfy a request. The allowance maximum is two seconds worth at the current rate-per-second. Requests reduce the allowance by the amount of the request. If the allowance is initially positive, the request is fulfilled immediately. If the allowance is negative, the allowance is topped up based on the elapsed time, waiting until it is positive again. If multiple threads are contending for the allowance, normal thread scheduling and synchronization primitives influence the order.

If an InterruptedException is caught, zero is returned, failing the validation.

The throttling of resource use is decoupled from the underlying resource implementation and only delays the start of resource consumption not the rate of consumption.

Overrides:

validate in class NotifyingMeter

Parameters:

amount - the amount requested

id - the ResourceId for the resource instance; may be null

previous - the previous meter value

Returns:

the value approved

getCurrentRate

public final long getCurrentRate()

Returns an estimate of the current rate in amount per second.

Returns:

an estimate of the current rate in amount per second

getRatePerSec

public final long getRatePerSec()

Returns the current throttle rate per second.

Returns:

the current throttle rate per second

setRatePerSec

public final long setRatePerSec(long ratePerSec)

Sets the throttle rate per second.

Parameters:

ratePerSec - the rate per second; must be greater than zero

Returns:

the previous throttle rate per second

Throws:

IllegalArgumentException - if ratePerSec is less than or equal to zero

toString

public String toString()

Description copied from class: SimpleMeter

Returns a string representation of the meter.

Overrides:

toString in class SimpleMeter

Returns:

a string representation of the meter