org.osgi.service.resourcemonitoring

Interface ResourceMonitor<T>

Type Parameters:

T - The type for the Resource.

All Known Subinterfaces:

CPUMonitor, DiskStorageMonitor, MemoryMonitor, SocketMonitor, ThreadMonitor

public interface ResourceMonitor<T>

Representation of the state of a resource for a resource context.

ResourceMonitor objects are returned by the ResourceContext.getMonitor(String) method.

The ResourceMonitor object may be used to:

• Enable/Disable the monitoring of the corresponding resource type for the corresponding resource context
• View the current usage of the resource by this resource context

A resource monitor can have a sampling period, a monitored period, or both. For example, for CPU monitoring, the resource monitor implementation can get the CPU usage of the running threads once per minute, and calculate the CPU usage per context in percentages based on the last ten such measurements. This could make a 60 000 milliseconds sampling period, and a 600 000 milliseconds monitored period.

Method Summary

Modifier and Type	Method and Description
void	delete() Disable and delete this instance of Resource Monitor.
void	disable() Disable the monitoring of this resource type for the resource context associated with this monitor instance.
void	enable() Enable the monitoring of this resource type for the resource context associated with this monitor instance.
boolean	equals(Object resourceMonitor) Checks if resourceMonitor is equals to the current instance.
ResourceContext	getContext() Returns the resource context that this monitor belongs to
long	getMonitoredPeriod() Returns the time period for which the usage of this resource type is monitored.
String	getResourceType() The name of the resource type that this monitor represents
long	getSamplingPeriod() Returns the sampling period for this resource type.
Comparable<T>	getUsage() Returns an object representing the current usage of this resource type by this resource context.
int	hashCode() Retrieves the hashCode value of this ResourceMonitor.
boolean	isDeleted() Returns true if the ResourceMonitor instance has been deleted, that is the delete() method has been called previously.
boolean	isEnabled() Checks if the monitoring for this resource type is enabled for this resource context

Method Detail

getContext

ResourceContext getContext()

Returns the resource context that this monitor belongs to

Returns:

The associated ResourceContext

getResourceType

String getResourceType()

The name of the resource type that this monitor represents

Returns:

The name of the monitored resource type

delete

void delete()
     throws ResourceMonitorException

Disable and delete this instance of Resource Monitor. This method MUST update the list of ResourceMonitor instances hold by the Resource Context (getContext().removeMonitor(this)).

Throws:

ResourceMonitorException - For example, when the monitor can't be removed from the ResourceContext.

isEnabled

boolean isEnabled()

Checks if the monitoring for this resource type is enabled for this resource context

Returns:

true if monitoring for this resource type is enabled for this context, false otherwise

isDeleted

boolean isDeleted()

Returns true if the ResourceMonitor instance has been deleted, that is the delete() method has been called previously.

Returns:

true if deleted.

enable

void enable()
     throws ResourceMonitorException

Enable the monitoring of this resource type for the resource context associated with this monitor instance. This method SHOULD also update the current resource consumption value (to take into account all previous resource allocations and releases occurred during the time the monitor was disabled).

Throws:

ResourceMonitorException - if the ResourceMonitor instance can not be enabled (for example, some MemoryMonitor implementations evaluate the memory consumption by tracking memory allocation operation at runtime. This kind of Monitor can not get instantaneous memory value. Such Monitor instances need to be enabled at starting time.). if the ResourceMonitor instance has been previously deleted

disable

void disable()
      throws ResourceMonitorException

Disable the monitoring of this resource type for the resource context associated with this monitor instance. The resource usage is not available until it is enabled again.

Throws:

ResourceMonitorException - if the ResourceMonitor instance has been previously deleted

getUsage

Comparable<T> getUsage()
                throws ResourceMonitorException

Returns an object representing the current usage of this resource type by this resource context.

Returns:

The current usage of this resource type.

Throws:

ResourceMonitorException - if the ResourceMonitor instance is not enabled.

getSamplingPeriod

long getSamplingPeriod()

Returns the sampling period for this resource type.

Returns:

The sampling period in milliseconds, or -1 if a sampling period is not relevant for this resource type.

getMonitoredPeriod

long getMonitoredPeriod()

Returns the time period for which the usage of this resource type is monitored.

Returns:

The monitored period in milliseconds, or -1 if a monitored period is not relevant for this resource type.

equals

boolean equals(Object resourceMonitor)

Checks if resourceMonitor is equals to the current instance. A ResourceMonitor rm1 is equals to a ResourceMonitor rm2 if rm1.getContext().equals(rm2.getContext()) and r1.getType().equals(rm2.getType()).

Overrides:

equals in class Object

Parameters:

resourceMonitor -

Returns:

true if the current instance is equals to the provided resourceMonitor

hashCode

int hashCode()

Retrieves the hashCode value of this ResourceMonitor. The hashCode value is based on the hashCode value of the associated ResourceContext and the hashCode value of the type.

Overrides:

hashCode in class Object

Returns:

hashcode