org.jolokia.backend.executor

Class AbstractMBeanServerExecutor

java.lang.Object

org.jolokia.backend.executor.AbstractMBeanServerExecutor

All Implemented Interfaces:

EventListener, NotificationListener, MBeanServerExecutor

Direct Known Subclasses:

MBeanServerExecutorLocal

public abstract class AbstractMBeanServerExecutor
extends Object
implements MBeanServerExecutor, NotificationListener

Base class for providing access to the list of MBeanServer handled by this agent.

Since:

22.01.13

Author:

roland

Nested Class Summary

Nested classes/interfaces inherited from interface org.jolokia.backend.executor.MBeanServerExecutor

MBeanServerExecutor.MBeanAction<R>, MBeanServerExecutor.MBeanEachCallback

Constructor Summary

Constructors

Constructor and Description
AbstractMBeanServerExecutor()

Method Summary

Modifier and Type	Method and Description
<T> T	call(ObjectName pObjectName, MBeanServerExecutor.MBeanAction<T> pMBeanAction, Object... pExtraArgs) Call an action an the first MBeanServer on which the action does not throw an InstanceNotFoundException will considered to be successful and this method returns with the return value of the succesful action.
void	each(ObjectName pObjectName, MBeanServerExecutor.MBeanEachCallback pCallback) Iterate over all MBeanServers managed and call the handler via a callback.
protected MBeanServerConnection	getJolokiaMBeanServer() Override this method if you want to provide a Jolokia private MBeanServer.
protected abstract Set<MBeanServerConnection>	getMBeanServers() Get all MBeanServers
void	handleNotification(Notification pNotification, Object pHandback)
boolean	hasMBeansListChangedSince(long pTimestamp) Check whether the set of MBeans in all managed MBeanServer has been changed since the given time.
Set<ObjectName>	queryNames(ObjectName pObjectName) Query all MBeanServer and return the union of all results
protected void	registerForMBeanNotifications() Add this executor as listener for MBeanServer notification so that we can update the local timestamp for when the set of registered MBeans has changed last.
void	unregisterFromMBeanNotifications() Unregister us as listener from every registered server

Methods inherited from class java.lang.Object

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

Constructor Detail

AbstractMBeanServerExecutor

public AbstractMBeanServerExecutor()

Method Detail

getMBeanServers

protected abstract Set<MBeanServerConnection> getMBeanServers()

Get all MBeanServers

Returns:

all MBeanServers in the merge order

getJolokiaMBeanServer

protected MBeanServerConnection getJolokiaMBeanServer()

Override this method if you want to provide a Jolokia private MBeanServer. Note, that this method should only return a non-null value, if the Jolokia private MBean Server has some MBeans registered

Returns:

the Jolokia MBeanServer

each

public void each(ObjectName pObjectName,
                 MBeanServerExecutor.MBeanEachCallback pCallback)
          throws IOException,
                 ReflectionException,
                 MBeanException

Iterate over all MBeanServers managed and call the handler via a callback. If is null or a pattern, the MBean names are queried on each MBeanServer and feed into the callback. If it is a full object name, then all MBeanServers are called with this object name in turn.

Specified by:

each in interface MBeanServerExecutor

Parameters:

pObjectName - object name to lookup, which can be a pattern in which case a query is performed.

pCallback - the action to be called for each MBean found on every server

Throws:

IOException

ReflectionException

MBeanException

call

public <T> T call(ObjectName pObjectName,
                  MBeanServerExecutor.MBeanAction<T> pMBeanAction,
                  Object... pExtraArgs)
           throws IOException,
                  ReflectionException,
                  MBeanException,
                  AttributeNotFoundException,
                  InstanceNotFoundException

Call an action an the first MBeanServer on which the action does not throw an InstanceNotFoundException will considered to be successful and this method returns with the return value of the succesful action. If no action was succesful, an IllegalArgumentException is raised (containing the last InstanceNotFoundException from the last tried server)

Specified by:

call in interface MBeanServerExecutor

Type Parameters:

T - type of the return value

Parameters:

pObjectName - objectname given through to the action

pMBeanAction - the action to call

pExtraArgs - any extra args given also to the action

Returns:

the return value of the succesful action

Throws:

IOException

ReflectionException

MBeanException - if the JMX call causes an issue

AttributeNotFoundException

InstanceNotFoundException

queryNames

public Set<ObjectName> queryNames(ObjectName pObjectName)
                           throws IOException

Query all MBeanServer and return the union of all results

Specified by:

queryNames in interface MBeanServerExecutor

Parameters:

pObjectName - pattern to query for. If null, then all MBean of all MBeanServers are returned

Returns:

the found MBeans

Throws:

IOException - if called remotely and an IOError occured.

registerForMBeanNotifications

protected void registerForMBeanNotifications()

Add this executor as listener for MBeanServer notification so that we can update the local timestamp for when the set of registered MBeans has changed last.

unregisterFromMBeanNotifications

public void unregisterFromMBeanNotifications()

Unregister us as listener from every registered server

handleNotification

public void handleNotification(Notification pNotification,
                               Object pHandback)

Specified by:

handleNotification in interface NotificationListener

hasMBeansListChangedSince

public boolean hasMBeansListChangedSince(long pTimestamp)

Check whether the set of MBeans in all managed MBeanServer has been changed since the given time. The input is the epoch time in seconds, however, milliseconds would be much more appropriate. However, the Jolokia responses contain currently time measured in seconds. This should be changed in a future version, but this implies a quite heavy API changed (and if this is changed, the key "timestamp" should be changed to "time", too, in order to fail early in case of problems). In order to avoid inconsistencies for sub-second updates, we are comparing conservatively (so hasBeenUpdated might return "true" more often than required).

Specified by:

hasMBeansListChangedSince in interface MBeanServerExecutor

Parameters:

pTimestamp - seconds since 1.1.1970

Returns:

true if the MBeans has been updated since this time, false otherwise