org.rhq.core.pc.util
Class ComponentUtil

java.lang.Object
  org.rhq.core.pc.util.ComponentUtil

public class ComponentUtil
extends Object

Some static utilities for use with component objects.

Author:

John Mazzitelli

Constructor Summary

ComponentUtil()

Method Summary

static ResourceComponent	fetchResourceComponent(int resourceId)
static <T> T	getComponent(int resourceId, Class<T> facetInterface, FacetLockType lockType, long timeout, boolean daemonThread, boolean onlyIfStarted) Gets the given facet interface for the resource identified with the given ID.
static org.rhq.core.domain.resource.ResourceType	getResourceType(int resourceId) Gets the Resource type of the Resource identified with the given ID.

Methods inherited from class java.lang.Object

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

Constructor Detail

ComponentUtil

public ComponentUtil()

Method Detail

getResourceType

public static org.rhq.core.domain.resource.ResourceType getResourceType(int resourceId)
                                                                 throws PluginContainerException

Gets the Resource type of the Resource identified with the given ID. An exception is thrown if it cannot be determined.

Parameters:

resourceId - the Resource id

Returns:

the Resource's ResourceType

Throws:

PluginContainerException - if the Resource is not known

getComponent

public static <T> T getComponent(int resourceId,
                                 Class<T> facetInterface,
                                 FacetLockType lockType,
                                 long timeout,
                                 boolean daemonThread,
                                 boolean onlyIfStarted)
                      throws PluginContainerException

Gets the given facet interface for the resource identified with the given ID. If the resource does not have a valid resource component associated with it or if it does not support the given facet, an exception is thrown. If the resource component is not yet started and onlyIfStarted is true, an exception will be thrown. Under most conditions when the plugin container managers need components, those components must be in the started state. This method can ensure that the component will only be returned if it is started.

The lockType defines how the caller wants to synchronize access to the facet method calls. If it is FacetLockType.NONE, the returned object is the component itself and will allow immediate and concurrent access to the component without synchronization. If it is FacetLockType.READ or FacetLockType.WRITE, the returned object is actually a proxy to the component that restricts access to the component's facet methods by synchronizing on the component's read or write lock. You would request synchronized access to a component if you want to make calls to the facet interface that require that it not run concurrently with any other component call in any other facet. For example, if you want to update a configuration via the configuration facet, you would ask for a write lock to prohibit any other facet call from concurrently being made. This will ensure that the configuration update will not occur at the same time an operation facet method call was made.

Parameters:

resourceId - identifies the resource whose facet component interface is to be returned

facetInterface - the resource component's facet type that is to be returned

lockType - how access to the facet should be synchronized

timeout - if the method invocation thread has not completed after this many milliseconds, interrupt it; value must be positive

daemonThread - whether or not the thread used for the invocation should be a daemon thread

onlyIfStarted - if true, and the component is not started, an exception is thrown

Returns:

the resource's T component interface

Throws:

PluginContainerException - if the resource does not have a component or it does not support the given facet interface or it is not started and onlyIfStarted is true

See Also:

ResourceContainer.createResourceComponentProxy(Class, FacetLockType, long, boolean, boolean)

fetchResourceComponent

public static ResourceComponent fetchResourceComponent(int resourceId)