jdk.management.resource

Class ResourceContextFactory

java.lang.Object

jdk.management.resource.ResourceContextFactory

public final class ResourceContextFactory
extends Object

The ResourceContextFactory provides access to ResourceContext functions. The factory provides methods to:

• Return the ResourceContextFactory instance and checks if the API is accessible to the caller
• Check if ResourceContexts are enabled
• Return a new ResourceContext
• Return a ResourceContext by name
• Return the ResourceContext bound to the current thread
• Return the UnassignedContext used for all unbound threads
• Return the TotalsContext that tracks totals of all contexts
• Return a Stream of the ResourceContexts
• Return the supported ResourceTypes

The getInstance method checks if there is a SecurityManager installed and the RuntimePermission("jdk.management.resource.getResourceContextFactory") is allowed. The reference to the ResourceContextFactory is a capability and should not be shared.

Threads that exist when the ResourceContextFactory is initialized are bound to the unassignedContext if they are not system threads. System threads ( with (thread.getThreadGroup().getParent() == null ) are not bound to the unassignedContext. The resources used by system threads are not recorded.

Since:

8u40

Method Summary

Modifier and Type	Method and Description
Stream<ResourceContext>	contexts() Returns a Stream of the existing ResourceContexts.
ResourceContext	create(String name) Create a new ResourceContext.
static ResourceContextFactory	getInstance() Returns the factory for ResourceContexts if enabled in the runtime.
ResourceRequest	getResourceRequest(ResourceType type) Returns the ResourceRequest for the current ResourceContext and ResourceType.
ResourceContext	getThreadContext() Returns the ResourceContext associated with the current thread.
ResourceContext	getThreadContext(Thread thread) Returns the ResourceContext associated with the thread.
ResourceContext	getTotalsContext() Returns a ResourceContext that provides the totals for all ResourceContexts.
ResourceContext	getUnassignedContext() Returns the ResourceContext that is the default when a thread is not associated with a ResourceContext.
static boolean	isEnabled() Returns true if and only if ResourceManagement is enabled.
ResourceContext	lookup(String name) Returns the ResourceContext given by name.
Set<ResourceType>	supportedResourceTypes() Returns a read-only Set of the builtin ResourceTypes available in the current runtime.

Methods inherited from class java.lang.Object

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

Method Detail

isEnabled

public static boolean isEnabled()

Returns true if and only if ResourceManagement is enabled. Refer to supportedResourceTypes() for the set of resources available.

Returns:

true if and only if ResourceManagement is enabled; otherwise false

Throws:

SecurityException - if a SecurityManager is installed and the RuntimePermission("jdk.management.resource.getResourceContextFactory) is denied

getInstance

public static ResourceContextFactory getInstance()

Returns the factory for ResourceContexts if enabled in the runtime.

Returns:

the factory for ResourceContexts

Throws:

SecurityException - if a SecurityManager is installed and the RuntimePermission("jdk.management.resource.getResourceContextFactory) is denied

create

public ResourceContext create(String name)

Create a new ResourceContext. A new empty ResourceContext with the specified name is created. The names of ResourceContexts must be unique. Use close to dispose of a ResourceContext.

Parameters:

name - a name for the ResourceContext

Returns:

a new ResourceContext

Throws:

IllegalArgumentException - if a ResourceContext with the name already exists.

UnsupportedOperationException - if the number of ResourceContexts exceeds implementation limits

lookup

public ResourceContext lookup(String name)

Returns the ResourceContext given by name.

Parameters:

name - the name

Returns:

the ResourceContext given by name; null if there is no ResourceContext with the name

getThreadContext

public ResourceContext getThreadContext()

Returns the ResourceContext associated with the current thread.

Returns:

the ResourceContext associated with the current thread; the unassigned context if the thread is not associated with any context

getThreadContext

public ResourceContext getThreadContext(Thread thread)

Returns the ResourceContext associated with the thread.

Parameters:

thread - the thread to query

Returns:

the ResourceContext associated with the current thread; the unassigned context if the thread is not associated with any context

getResourceRequest

public ResourceRequest getResourceRequest(ResourceType type)

Returns the ResourceRequest for the current ResourceContext and ResourceType. If there is no ResourceContext associated with the current thread, the unassigned context is used.

Parameters:

type - the ResourceType of the resource making the request

Returns:

a ResourceRequest; null if there is no ResourceMeter with the type in the ResourceContext

getUnassignedContext

public ResourceContext getUnassignedContext()

Returns the ResourceContext that is the default when a thread is not associated with a ResourceContext.

Returns:

the unassigned ResourceContext

getTotalsContext

public ResourceContext getTotalsContext()

Returns a ResourceContext that provides the totals for all ResourceContexts. The meters reflect the sum of all other ResourceContexts plus the final counts of removed ResourceContexts. These meters are read only and are only updated by changes to active ResourceContexts.

Returns:

the totals ResourceContext

contexts

public Stream<ResourceContext> contexts()

Returns a Stream of the existing ResourceContexts.

Returns:

a Stream of the existing ResourceContexts

supportedResourceTypes

public Set<ResourceType> supportedResourceTypes()

Returns a read-only Set of the builtin ResourceTypes available in the current runtime.

Returns:

a read-only Set of the builtin ResourceTypes available in the current runtime; non-null