com.redhat.thermostat.backend

Class VmListenerBackend

java.lang.Object

com.redhat.thermostat.backend.BaseBackend

com.redhat.thermostat.backend.VmListenerBackend

All Implemented Interfaces:

VmStatusListener, Backend, Ordered

Direct Known Subclasses:

VmClassStatBackend, VmGcBackend, VmMemoryBackend

public abstract class VmListenerBackend
extends BaseBackend
implements VmStatusListener

This class is a convenient subclass of Backend (via BaseBackend) for those that need to attach VmUpdateListener in response to starting and stopping of JVMs on a host.

See Also:

VmStatusListener, Backend, BaseBackend

Nested Class Summary

Nested classes/interfaces inherited from interface com.redhat.thermostat.agent.VmStatusListener

VmStatusListener.Status

Field Summary

Fields inherited from interface com.redhat.thermostat.common.Ordered

ORDER_CPU_GROUP, ORDER_DEFAULT_GROUP, ORDER_IO_GROUP, ORDER_MEMORY_GROUP, ORDER_NETWORK_GROUP, ORDER_THREAD_GROUP, ORDER_USER_GROUP

Constructor Summary

Constructors

Constructor and Description
VmListenerBackend(String backendName, String description, String vendor, String version, boolean observeNewJvm, VmStatusListenerRegistrar registrar)
VmListenerBackend(String backendName, String description, String vendor, String version, VmStatusListenerRegistrar registrar)

Method Summary

Methods

Modifier and Type	Method and Description
boolean	activate() Activate the Backend.
protected abstract VmUpdateListener	createVmListener(int pid) Creates a new VmUpdateListener for the virtual machine specified by the pid.
boolean	deactivate() Deactivate the Backend.
boolean	isActive()
void	vmStatusChanged(VmStatusListener.Status newStatus, int pid)

Methods inherited from class com.redhat.thermostat.backend.BaseBackend

equals, getDescription, getName, getObserveNewJvm, getVendor, getVersion, hashCode, setObserveNewJvm, toString

Methods inherited from class java.lang.Object

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

Methods inherited from interface com.redhat.thermostat.common.Ordered

getOrderValue

Constructor Detail

VmListenerBackend

public VmListenerBackend(String backendName,
                 String description,
                 String vendor,
                 String version,
                 VmStatusListenerRegistrar registrar)

VmListenerBackend

public VmListenerBackend(String backendName,
                 String description,
                 String vendor,
                 String version,
                 boolean observeNewJvm,
                 VmStatusListenerRegistrar registrar)

Method Detail

activate

public boolean activate()

Activate the Backend. Based on the current configuration, begin pushing data to the Storage layer. If the Backend is already active, this method should have no effect.

This method is called by the framework when the Backend is registered.

Registers a VmUpdateListener to begin receiving VM lifecycle events. Subclasses should call super.activate() when overriding this method.

Specified by:

activate in interface Backend

Returns:

true if the backend was activated successfully or already active. false if there was an error

deactivate

public boolean deactivate()

Deactivate the Backend. The backend should release any resources that were obtained as a direct result of a call to Backend.activate(). If the Backend is not active, this method should have no effect

This method is called by the framework when the Backend is deregistered.

Unregisters the VmUpdateListener to stop receiving VM lifecycle events. Subclasses should call super.deactivate() when overriding this method.

Specified by:

deactivate in interface Backend

Returns:

true if the backend was successfully deactivated or already inactive. false if the backend is still active.

isActive

public boolean isActive()

Specified by:

isActive in interface Backend

Returns:

a boolean indicating whether the backend is currently active on this host

vmStatusChanged

public void vmStatusChanged(VmStatusListener.Status newStatus,
                   int pid)

Specified by:

vmStatusChanged in interface VmStatusListener

createVmListener

protected abstract VmUpdateListener createVmListener(int pid)

Creates a new VmUpdateListener for the virtual machine specified by the pid. This method is called when a new JVM is started or for JVMs already active when this Backend was activated.

Parameters:

pid - the process ID of the JVM

Returns:

a new listener for the VM specified by pid