JMXConnectorServer (Java SE 15 & JDK 15)
Description: declaration: module: java.management, package: javax.management.remote, class: JMXConnectorServer
Keywords: javax.management.remote.JMXConnectorServer class

Module java.management
Package javax.management.remote

# Class JMXConnectorServer

java.lang.Object
javax.management.NotificationBroadcasterSupport
javax.management.remote.JMXConnectorServer

All Implemented Interfaces:
  `MBeanRegistration`, `NotificationBroadcaster`, `NotificationEmitter`, `JMXAddressable`, `JMXConnectorServerMBean`

Direct Known Subclasses:
  `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.

Since:
  1.5

- ## Field Summary

  Fields
  Modifier and Type | Field | Description
  --- | --- | ---
  `static String` | `AUTHENTICATOR` | Name of the attribute that specifies the authenticator for a connector server.

- ## Constructor Summary

  Constructors
  Constructor | Description
  --- | ---
  `JMXConnectorServer()` | Constructs a connector server that will be registered as an MBean in the MBean server it is attached to.
  `JMXConnectorServer​(MBeanServer mbeanServer)` | Constructs a connector server that is attached to the given MBean server.

- ## Method Summary

  Modifier and Type | Method | Description
  --- | --- | ---
  `protected void` | `connectionClosed​(String connectionId, String message, Object userData)` | Called by a subclass when a client connection is closed normally.
  `protected void` | `connectionFailed​(String connectionId, String message, Object userData)` | Called by a subclass when a client connection fails.
  `protected void` | `connectionOpened​(String connectionId, String message, Object userData)` | Called by a subclass when a new client connection is opened.
  `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` | `preDeregister()` | Called by an MBean server when this connector server is unregistered from that MBean server.
  `ObjectName` | `preRegister​(MBeanServer mbs, ObjectName name)` | Called by an MBean server when this connector server is registered in that MBean server.
  `JMXConnector` | `toJMXConnector​(Map<String,​?> env)` | Returns a client stub for this connector server.

  ### Methods declared in class javax.management.NotificationBroadcasterSupport

  `addNotificationListener, handleNotification, sendNotification`

  ### Methods declared in class java.lang.Object

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

  ### Methods declared in interface javax.management.remote.JMXAddressable

  `getAddress`

  ### Methods declared in interface javax.management.remote.JMXConnectorServerMBean

  `getAddress, getAttributes, getConnectionIds, isActive, setMBeanServerForwarder, start, stop`

  ### Methods declared in interface javax.management.MBeanRegistration

  `postDeregister, postRegister`

  ### Methods declared in interface javax.management.NotificationBroadcaster

  `removeNotificationListener`

  ### Methods declared in interface javax.management.NotificationEmitter

  `removeNotificationListener`

- ## Field Details

  - ### AUTHENTICATOR

    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`.

    See Also:
      Constant Field Values

- ## Constructor Details

  - ### JMXConnectorServer

    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.

  - ### JMXConnectorServer

    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.

    Parameters:
      `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.

- ## Method Details

  - ### getMBeanServer

    public MBeanServer getMBeanServer()

    Returns the MBean server that this connector server is attached to.

    Returns:
      the MBean server that this connector server is attached to, or null if it is not yet attached to an MBean server.

  - ### toJMXConnector

    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();
         return JMXConnectorFactory.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`.

    Specified by:
      `toJMXConnector` in interface `JMXConnectorServerMBean`
    Parameters:
      `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.
    Returns:
      a client stub that can be used to make a new connection to this connector server.
    Throws:
      `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.

  - ### getNotificationInfo

    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.

    Specified by:
      `getNotificationInfo` in interface `NotificationBroadcaster`
    Returns:
      the array of possible notifications.

  - ### connectionOpened

    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 `JMXConnectorServerMBean.getConnectionIds()`, then emits a `JMXConnectionNotification` with type `JMXConnectionNotification.OPENED`.

    Parameters:
      `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()`.
    Throws:
      `NullPointerException` - if `connectionId` is null.

  - ### connectionClosed

    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 `JMXConnectorServerMBean.getConnectionIds()`, then emits a `JMXConnectionNotification` with type `JMXConnectionNotification.CLOSED`.

    Parameters:
      `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()`.
    Throws:
      `NullPointerException` - if `connectionId` is null.

  - ### connectionFailed

    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 `JMXConnectorServerMBean.getConnectionIds()`, then emits a `JMXConnectionNotification` with type `JMXConnectionNotification.FAILED`.

    Parameters:
      `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()`.
    Throws:
      `NullPointerException` - if `connectionId` is null.

  - ### preRegister

    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.

    Specified by:
      `preRegister` in interface `MBeanRegistration`
    Parameters:
      `mbs` - the MBean server in which this connection server is being registered.
      `name` - The object name of the MBean.
    Returns:
      The name under which the MBean is to be registered.
    Throws:
      `NullPointerException` - if `mbs` or `name` is null.

  - ### preDeregister

    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.

    Specified by:
      `preDeregister` in interface `MBeanRegistration`
    Throws:
      `IOException` - if thrown by the `stop` method.
      `Exception` - This exception will be caught by the MBean server and re-thrown as an `MBeanRegistrationException`.