/*
* Copyright (c) 2003, 2008, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
package javax.management.remote;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import javax.management.MBeanNotificationInfo;
import javax.management.MBeanRegistration;
import javax.management.MBeanServer;
import javax.management.Notification;
import javax.management.NotificationBroadcasterSupport;
import javax.management.ObjectName;
/**
* <p>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.</p>
*
* <p>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.</p>
*
* <p>A connector server is inactive when created. It only starts
* listening for client connections when the {@link #start() start}
* method is called. A connector server stops listening for client
* connections when the {@link #stop() stop} method is called or when
* the connector server is unregistered from its MBean server.</p>
*
* <p>Stopping a connector server does not unregister it from its
* MBean server. A connector server once stopped cannot be
* restarted.</p>
*
* <p>Each time a client connection is made or broken, a notification
* of class {@link JMXConnectionNotification} is emitted.</p>
*
* @since 1.5
*/
public abstract class JMXConnectorServer
extends NotificationBroadcasterSupport
implements JMXConnectorServerMBean, MBeanRegistration, JMXAddressable {
/**
* <p>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 {@link
* JMXAuthenticator}.</p>
*/
public static final String AUTHENTICATOR =
"jmx.remote.authenticator";
/**
* <p>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 <code>createMBean</code>
* methods when creating, within an MBean server, a connector
* server that makes it available remotely.</p>
*/
public JMXConnectorServer() {
this(null);
}
/**
* <p>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.</p>
*
* @param 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 JMXConnectorServer(MBeanServer mbeanServer) {
this.mbeanServer = mbeanServer;
}
/**
* <p>Returns the MBean server that this connector server is
* attached to.</p>
*
* @return the MBean server that this connector server is attached
* to, or null if it is not yet attached to an MBean server.
*/
public synchronized MBeanServer getMBeanServer() {
return mbeanServer;
}
public synchronized void setMBeanServerForwarder(MBeanServerForwarder mbsf)
{
if (mbsf == null)
throw new IllegalArgumentException("Invalid null argument: mbsf");
if (mbeanServer != null) mbsf.setMBeanServer(mbeanServer);
mbeanServer = mbsf;
}
public String[] getConnectionIds() {
synchronized (connectionIds) {
return connectionIds.toArray(new String[connectionIds.size()]);
}
}
/**
* <p>Returns a client stub for this connector server. A client
* stub is a serializable object whose {@link
* JMXConnector#connect(Map) connect} method can be used to make
* one new connection to this connector server.</p>
*
* <p>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).</p>
*
* <p>The default implementation of this method uses {@link
* #getAddress} and {@link JMXConnectorFactory} to generate the
* stub, with code equivalent to the following:</p>
*
* <pre>
* JMXServiceURL addr = {@link #getAddress() getAddress()};
* return {@link JMXConnectorFactory#newJMXConnector(JMXServiceURL, Map)
* JMXConnectorFactory.newJMXConnector(addr, env)};
* </pre>
*
* <p>A connector server for which this is inappropriate must
* override this method so that it either implements the
* appropriate logic or throws {@link
* UnsupportedOperationException}.</p>
*
* @param env client connection parameters of the same sort that
* could be provided to {@link JMXConnector#connect(Map)
* JMXConnector.connect(Map)}. Can be null, which is equivalent
* to an empty map.
*
* @return a client stub that can be used to make a new connection
* to this connector server.
*
* @exception UnsupportedOperationException if this connector
* server does not support the generation of client stubs.
*
* @exception IllegalStateException if the JMXConnectorServer is
* not started (see {@link JMXConnectorServerMBean#isActive()}).
*
* @exception IOException if a communications problem means that a
* stub cannot be created.
**/
public JMXConnector toJMXConnector(Map<String,?> env)
throws IOException
{
if (!isActive()) throw new
IllegalStateException("Connector is not active");
JMXServiceURL addr = getAddress();
return JMXConnectorFactory.newJMXConnector(addr, env);
}
/**
* <p>Returns an array indicating the notifications that this MBean
* sends. The implementation in <code>JMXConnectorServer</code>
* returns an array with one element, indicating that it can emit
* notifications of class {@link 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.</p>
*
* @return the array of possible notifications.
*/
@Override
public MBeanNotificationInfo[] getNotificationInfo() {
final String[] types = {
JMXConnectionNotification.OPENED,
JMXConnectionNotification.CLOSED,
JMXConnectionNotification.FAILED,
};
final String className = JMXConnectionNotification.class.getName();
final String description =
"A client connection has been opened or closed";
return new MBeanNotificationInfo[] {
new MBeanNotificationInfo(types, className, description),
};
}
/**
* <p>Called by a subclass when a new client connection is opened.
* Adds <code>connectionId</code> to the list returned by {@link
* #getConnectionIds()}, then emits a {@link
* JMXConnectionNotification} with type {@link
* JMXConnectionNotification#OPENED}.</p>
*
* @param connectionId the ID of the new connection. This must be
* different from the ID of any connection previously opened by
* this connector server.
*
* @param message the message for the emitted {@link
* JMXConnectionNotification}. Can be null. See {@link
* Notification#getMessage()}.
*
* @param userData the <code>userData</code> for the emitted
* {@link JMXConnectionNotification}. Can be null. See {@link
* Notification#getUserData()}.
*
* @exception NullPointerException if <code>connectionId</code> is
* null.
*/
protected void connectionOpened(String connectionId,
String message,
Object userData) {
if (connectionId == null)
throw new NullPointerException("Illegal null argument");
synchronized (connectionIds) {
connectionIds.add(connectionId);
}
sendNotification(JMXConnectionNotification.OPENED, connectionId,
message, userData);
}
/**
* <p>Called by a subclass when a client connection is closed
* normally. Removes <code>connectionId</code> from the list returned
* by {@link #getConnectionIds()}, then emits a {@link
* JMXConnectionNotification} with type {@link
* JMXConnectionNotification#CLOSED}.</p>
*
* @param connectionId the ID of the closed connection.
*
* @param message the message for the emitted {@link
* JMXConnectionNotification}. Can be null. See {@link
* Notification#getMessage()}.
*
* @param userData the <code>userData</code> for the emitted
* {@link JMXConnectionNotification}. Can be null. See {@link
* Notification#getUserData()}.
*
* @exception NullPointerException if <code>connectionId</code>
* is null.
*/
protected void connectionClosed(String connectionId,
String message,
Object userData) {
if (connectionId == null)
throw new NullPointerException("Illegal null argument");
synchronized (connectionIds) {
connectionIds.remove(connectionId);
}
sendNotification(JMXConnectionNotification.CLOSED, connectionId,
message, userData);
}
/**
* <p>Called by a subclass when a client connection fails.
* Removes <code>connectionId</code> from the list returned by
* {@link #getConnectionIds()}, then emits a {@link
* JMXConnectionNotification} with type {@link
* JMXConnectionNotification#FAILED}.</p>
*
* @param connectionId the ID of the failed connection.
*
* @param message the message for the emitted {@link
* JMXConnectionNotification}. Can be null. See {@link
* Notification#getMessage()}.
*
* @param userData the <code>userData</code> for the emitted
* {@link JMXConnectionNotification}. Can be null. See {@link
* Notification#getUserData()}.
*
* @exception NullPointerException if <code>connectionId</code> is
* null.
*/
protected void connectionFailed(String connectionId,
String message,
Object userData) {
if (connectionId == null)
throw new NullPointerException("Illegal null argument");
synchronized (connectionIds) {
connectionIds.remove(connectionId);
}
sendNotification(JMXConnectionNotification.FAILED, connectionId,
message, userData);
}
private void sendNotification(String type, String connectionId,
String message, Object userData) {
Notification notif =
new JMXConnectionNotification(type,
getNotificationSource(),
connectionId,
nextSequenceNumber(),
message,
userData);
sendNotification(notif);
}
private synchronized Object getNotificationSource() {
if (myName != null)
return myName;
else
return this;
}
private static long nextSequenceNumber() {
synchronized (sequenceNumberLock) {
return sequenceNumber++;
}
}
// implements MBeanRegistration
/**
* <p>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 {@link #getMBeanServer()}
* method will return <code>mbs</code>.</p>
*
* <p>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.</p>
*
* @param mbs the MBean server in which this connection server is
* being registered.
*
* @param name The object name of the MBean.
*
* @return The name under which the MBean is to be registered.
*
* @exception NullPointerException if <code>mbs</code> or
* <code>name</code> is null.
*/
public synchronized ObjectName preRegister(MBeanServer mbs,
ObjectName name) {
if (mbs == null || name == null)
throw new NullPointerException("Null MBeanServer or ObjectName");
if (mbeanServer == null) {
mbeanServer = mbs;
myName = name;
}
return name;
}
public void postRegister(Boolean registrationDone) {
// do nothing
}
/**
* <p>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 {@link #stop stop} method.
* If the <code>stop</code> method throws an exception, the
* unregistration attempt will fail. It is recommended to call
* the <code>stop</code> method explicitly before unregistering
* the MBean.</p>
*
* @exception IOException if thrown by the {@link #stop stop} method.
*/
public synchronized void preDeregister() throws Exception {
if (myName != null && isActive()) {
stop();
myName = null; // just in case stop is buggy and doesn't stop
}
}
public void postDeregister() {
myName = null;
}
/**
* The MBeanServer used by this server to execute a client request.
*/
private MBeanServer mbeanServer = null;
/**
* The name used to registered this server in an MBeanServer.
* It is null if the this server is not registered or has been unregistered.
*/
private ObjectName myName;
private final List<String> connectionIds = new ArrayList<String>();
private static final int[] sequenceNumberLock = new int[0];
private static long sequenceNumber;
}