MBeanRegistration
, NotificationBroadcaster
, NotificationEmitter
, JMXAddressable
, JMXConnectorServerMBean
RMIConnectorServer
public abstract class JMXConnectorServer extends NotificationBroadcasterSupport implements JMXConnectorServerMBean, MBeanRegistration, JMXAddressable
Superclass of every connector server. A connector server is attached to an MBean server. It listens for client connection requests and creates a connection for each one.
A connector server is associated with an MBean server either by registering it in that MBean server, or by passing the MBean server to its constructor.
A connector server is inactive when created. It only starts listening for client connections when the start
method is called. A connector server stops listening for client connections when the stop
method is called or when the connector server is unregistered from its MBean server.
Stopping a connector server does not unregister it from its MBean server. A connector server once stopped cannot be restarted.
Each time a client connection is made or broken, a notification of class JMXConnectionNotification
is emitted.
Modifier and Type | Field | Description |
---|---|---|
static final String |
AUTHENTICATOR |
Name of the attribute that specifies the authenticator for a connector server. |
Constructor | Description |
---|---|
JMXConnectorServer() |
Constructs a connector server that will be registered as an MBean in the MBean server it is attached to. |
JMXConnectorServer |
Constructs a connector server that is attached to the given MBean server. |
Modifier and Type | Method | Description |
---|---|---|
protected void |
connectionClosed |
Called by a subclass when a client connection is closed normally. |
protected void |
connectionFailed |
Called by a subclass when a client connection fails. |
protected void |
connectionOpened |
Called by a subclass when a new client connection is opened. |
String[] |
getConnectionIds() |
The list of IDs for currently-open connections to this connector server. |
MBeanServer |
getMBeanServer() |
Returns the MBean server that this connector server is attached to. |
MBeanNotificationInfo[] |
getNotificationInfo() |
Returns an array indicating the notifications that this MBean sends. |
void |
postDeregister() |
Allows the MBean to perform any operations needed after having been unregistered in the MBean server. |
void |
postRegister |
Allows the MBean to perform any operations needed after having been registered in the MBean server or after the registration has failed. |
void |
preDeregister() |
Called by an MBean server when this connector server is unregistered from that MBean server. |
ObjectName |
preRegister |
Called by an MBean server when this connector server is registered in that MBean server. |
void |
setMBeanServerForwarder |
Inserts an object that intercepts requests for the MBean server that arrive through this connector server. |
JMXConnector |
toJMXConnector |
Returns a client stub for this connector server. |
addNotificationListener, handleNotification, removeNotificationListener, removeNotificationListener, sendNotification
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
getAddress
getAddress, getAttributes, isActive, start, stop
public static final String AUTHENTICATOR
Name of the attribute that specifies the authenticator for a connector server. The value associated with this attribute, if any, must be an object that implements the interface JMXAuthenticator
.
public JMXConnectorServer()
Constructs a connector server that will be registered as an MBean in the MBean server it is attached to. This constructor is typically called by one of the createMBean
methods when creating, within an MBean server, a connector server that makes it available remotely.
public JMXConnectorServer(MBeanServer mbeanServer)
Constructs a connector server that is attached to the given MBean server. A connector server that is created in this way can be registered in a different MBean server, or not registered in any MBean server.
mbeanServer
- the MBean server that this connector server is attached to. Null if this connector server will be attached to an MBean server by being registered in it.public MBeanServer getMBeanServer()
Returns the MBean server that this connector server is attached to.
public void setMBeanServerForwarder(MBeanServerForwarder mbsf)
JMXConnectorServerMBean
Inserts an object that intercepts requests for the MBean server that arrive through this connector server. This object will be supplied as the MBeanServer
for any new connection created by this connector server. Existing connections are unaffected.
This method can be called more than once with different MBeanServerForwarder
objects. The result is a chain of forwarders. The last forwarder added is the first in the chain. In more detail:
If this connector server is already associated with an MBeanServer
object, then that object is given to mbsf.setMBeanServer
. If doing so produces an exception, this method throws the same exception without any other effect.
If this connector is not already associated with an MBeanServer
object, or if the mbsf.setMBeanServer
call just mentioned succeeds, then mbsf
becomes this connector server's MBeanServer
.
setMBeanServerForwarder
in interface JMXConnectorServerMBean
mbsf
- the new MBeanServerForwarder
.public String[] getConnectionIds()
JMXConnectorServerMBean
The list of IDs for currently-open connections to this connector server.
getConnectionIds
in interface JMXConnectorServerMBean
public JMXConnector toJMXConnector(Map<String,?> env) throws IOException
Returns a client stub for this connector server. A client stub is a serializable object whose connect
method can be used to make one new connection to this connector server.
A given connector need not support the generation of client stubs. However, the connectors specified by the JMX Remote API do (JMXMP Connector and RMI Connector).
The default implementation of this method uses JMXConnectorServerMBean.getAddress()
and JMXConnectorFactory
to generate the stub, with code equivalent to the following:
JMXServiceURL addr =getAddress()
; returnJMXConnectorFactory.newJMXConnector(addr, env)
;
A connector server for which this is inappropriate must override this method so that it either implements the appropriate logic or throws UnsupportedOperationException
.
toJMXConnector
in interface JMXConnectorServerMBean
env
- client connection parameters of the same sort that could be provided to JMXConnector.connect(Map)
. Can be null, which is equivalent to an empty map.UnsupportedOperationException
- if this connector server does not support the generation of client stubs.IllegalStateException
- if the JMXConnectorServer is not started (see JMXConnectorServerMBean.isActive()
).IOException
- if a communications problem means that a stub cannot be created.public MBeanNotificationInfo[] getNotificationInfo()
Returns an array indicating the notifications that this MBean sends. The implementation in JMXConnectorServer
returns an array with one element, indicating that it can emit notifications of class JMXConnectionNotification
with the types defined in that class. A subclass that can emit other notifications should return an array that contains this element plus descriptions of the other notifications.
getNotificationInfo
in interface NotificationBroadcaster
protected void connectionOpened(String connectionId, String message, Object userData)
Called by a subclass when a new client connection is opened. Adds connectionId
to the list returned by getConnectionIds()
, then emits a JMXConnectionNotification
with type JMXConnectionNotification.OPENED
.
connectionId
- the ID of the new connection. This must be different from the ID of any connection previously opened by this connector server.message
- the message for the emitted JMXConnectionNotification
. Can be null. See Notification.getMessage()
.userData
- the userData
for the emitted JMXConnectionNotification
. Can be null. See Notification.getUserData()
.NullPointerException
- if connectionId
is null.protected void connectionClosed(String connectionId, String message, Object userData)
Called by a subclass when a client connection is closed normally. Removes connectionId
from the list returned by getConnectionIds()
, then emits a JMXConnectionNotification
with type JMXConnectionNotification.CLOSED
.
connectionId
- the ID of the closed connection.message
- the message for the emitted JMXConnectionNotification
. Can be null. See Notification.getMessage()
.userData
- the userData
for the emitted JMXConnectionNotification
. Can be null. See Notification.getUserData()
.NullPointerException
- if connectionId
is null.protected void connectionFailed(String connectionId, String message, Object userData)
Called by a subclass when a client connection fails. Removes connectionId
from the list returned by getConnectionIds()
, then emits a JMXConnectionNotification
with type JMXConnectionNotification.FAILED
.
connectionId
- the ID of the failed connection.message
- the message for the emitted JMXConnectionNotification
. Can be null. See Notification.getMessage()
.userData
- the userData
for the emitted JMXConnectionNotification
. Can be null. See Notification.getUserData()
.NullPointerException
- if connectionId
is null.public ObjectName preRegister(MBeanServer mbs, ObjectName name)
Called by an MBean server when this connector server is registered in that MBean server. This connector server becomes attached to the MBean server and its getMBeanServer()
method will return mbs
.
If this connector server is already attached to an MBean server, this method has no effect. The MBean server it is attached to is not necessarily the one it is being registered in.
preRegister
in interface MBeanRegistration
mbs
- the MBean server in which this connection server is being registered.name
- The object name of the MBean.NullPointerException
- if mbs
or name
is null.public void postRegister(Boolean registrationDone)
MBeanRegistration
If the implementation of this method throws a RuntimeException
or an Error
, the MBean Server will rethrow those inside a RuntimeMBeanException
or RuntimeErrorException
, respectively. However, throwing an exception in postRegister
will not change the state of the MBean: if the MBean was already registered (registrationDone
is true
), the MBean will remain registered.
This might be confusing for the code calling createMBean()
or registerMBean()
, as such code might assume that MBean registration has failed when such an exception is raised. Therefore it is recommended that implementations of postRegister
do not throw Runtime Exceptions or Errors if it can be avoided.
postRegister
in interface MBeanRegistration
registrationDone
- Indicates whether or not the MBean has been successfully registered in the MBean server. The value false means that the registration phase has failed.public void preDeregister() throws Exception
Called by an MBean server when this connector server is unregistered from that MBean server. If this connector server was attached to that MBean server by being registered in it, and if the connector server is still active, then unregistering it will call the stop
method. If the stop
method throws an exception, the unregistration attempt will fail. It is recommended to call the stop
method explicitly before unregistering the MBean.
preDeregister
in interface MBeanRegistration
IOException
- if thrown by the stop
method.Exception
- This exception will be caught by the MBean server and re-thrown as an MBeanRegistrationException
.public void postDeregister()
MBeanRegistration
If the implementation of this method throws a RuntimeException
or an Error
, the MBean Server will rethrow those inside a RuntimeMBeanException
or RuntimeErrorException
, respectively. However, throwing an exception in postDeregister
will not change the state of the MBean: the MBean was already successfully deregistered and will remain so.
This might be confusing for the code calling unregisterMBean()
, as it might assume that MBean deregistration has failed. Therefore it is recommended that implementations of postDeregister
do not throw Runtime Exceptions or Errors if it can be avoided.
postDeregister
in interface MBeanRegistration
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Documentation extracted from Debian's OpenJDK Development Kit package.
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https://docs.oracle.com/en/java/javase/21/docs/api/java.management/javax/management/remote/JMXConnectorServer.html