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package javax.management.remote;

import java.io.IOException;

import java.util.Map;

/**

 * <p>MBean interface for connector servers.  A JMX API connector server

 * is attached to an MBean server, and establishes connections to that

 * MBean server for remote clients.</p>

 *

 * <p>A newly-created connector server is <em>inactive</em>, and does

 * not yet listen for connections.  Only when its {@link #start start}

 * method has been called does it start listening for connections.</p>

 *

 * @since 1.5

 */

public interface JMXConnectorServerMBean {

    /**

     * <p>Activates the connector server, that is, starts listening for

     * client connections.  Calling this method when the connector

     * server is already active has no effect.  Calling this method

     * when the connector server has been stopped will generate an

     * {@link IOException}.</p>

     *

     * @exception IOException if it is not possible to start listening

     * or if the connector server has been stopped.

     *

     * @exception IllegalStateException if the connector server has

     * not been attached to an MBean server.

     */

    public void start() throws IOException;

    /**

     * <p>Deactivates the connector server, that is, stops listening for

     * client connections.  Calling this method will also close all

     * client connections that were made by this server.  After this

     * method returns, whether normally or with an exception, the

     * connector server will not create any new client

     * connections.</p>

     *

     * <p>Once a connector server has been stopped, it cannot be started

     * again.</p>

     *

     * <p>Calling this method when the connector server has already

     * been stopped has no effect.  Calling this method when the

     * connector server has not yet been started will disable the

     * connector server object permanently.</p>

     *

     * <p>If closing a client connection produces an exception, that

     * exception is not thrown from this method.  A {@link

     * JMXConnectionNotification} with type {@link

     * JMXConnectionNotification#FAILED} is emitted from this MBean

     * with the connection ID of the connection that could not be

     * closed.</p>

     *

     * <p>Closing a connector server is a potentially slow operation.

     * For example, if a client machine with an open connection has

     * crashed, the close operation might have to wait for a network

     * protocol timeout.  Callers that do not want to block in a close

     * operation should do it in a separate thread.</p>

     *

     * @exception IOException if the server cannot be closed cleanly.

     * When this exception is thrown, the server has already attempted

     * to close all client connections.  All client connections are

     * closed except possibly those that generated exceptions when the

     * server attempted to close them.

     */

    public void stop() throws IOException;

    /**

     * <p>Determines whether the connector server is active.  A connector

     * server starts being active when its {@link #start start} method

     * returns successfully and remains active until either its

     * {@link #stop stop} method is called or the connector server

     * fails.</p>

     *

     * @return true if the connector server is active.

     */

    public boolean isActive();

    /**

     * <p>Inserts an object that intercepts requests for the MBean server

     * that arrive through this connector server.  This object will be

     * supplied as the <code>MBeanServer</code> for any new connection

     * created by this connector server.  Existing connections are

     * unaffected.</p>

     *

     * <p>This method can be called more than once with different

     * {@link MBeanServerForwarder} objects.  The result is a chain

     * of forwarders.  The last forwarder added is the first in the chain.

     * In more detail:</p>

     *

     * <ul>

     * <li><p>If this connector server is already associated with an

     * <code>MBeanServer</code> object, then that object is given to

     * {@link MBeanServerForwarder#setMBeanServer

     * mbsf.setMBeanServer}.  If doing so produces an exception, this

     * method throws the same exception without any other effect.</p>

     *

     * <li><p>If this connector is not already associated with an

     * <code>MBeanServer</code> object, or if the

     * <code>mbsf.setMBeanServer</code> call just mentioned succeeds,

     * then <code>mbsf</code> becomes this connector server's

     * <code>MBeanServer</code>.</p>

     * </ul>

     *

     * <p>A connector server may support two chains of forwarders,

     * a system chain and a user chain.  See {@link

     * JMXConnectorServer#setSystemMBeanServerForwarder} for details.</p>

     *

     * @param mbsf the new <code>MBeanServerForwarder</code>.

     *

     * @exception IllegalArgumentException if the call to {@link

     * MBeanServerForwarder#setMBeanServer mbsf.setMBeanServer} fails

     * with <code>IllegalArgumentException</code>.  This includes the

     * case where <code>mbsf</code> is null.

     *

     * @see JMXConnectorServer#setSystemMBeanServerForwarder

     */

    public void setMBeanServerForwarder(MBeanServerForwarder mbsf);

    /**

     * <p>The list of IDs for currently-open connections to this

     * connector server.</p>

     *

     * @return a new string array containing the list of IDs.  If

     * there are no currently-open connections, this array will be

     * empty.

     */

    public String[] getConnectionIds();

    /**

     * <p>The address of this connector server.</p>

     * <p>

     * The address returned may not be the exact original {@link JMXServiceURL}

     * that was supplied when creating the connector server, since the original

     * address may not always be complete. For example the port number may be

     * dynamically allocated when starting the connector server. Instead the

     * address returned is the actual {@link JMXServiceURL} of the

     * {@link JMXConnectorServer}. This is the address that clients supply

     * to {@link JMXConnectorFactory#connect(JMXServiceURL)}.

     * </p>

     * <p>Note that the address returned may be {@code null} if

     *    the {@code JMXConnectorServer} is not yet {@link #isActive active}.

     * </p>

     *

     * @return the address of this connector server, or null if it

     * does not have one.

     */

    public JMXServiceURL getAddress();

    /**

     * <p>The attributes for this connector server.</p>

     *

     * @return a read-only map containing the attributes for this

     * connector server.  Attributes whose values are not serializable

     * are omitted from this map.  If there are no serializable

     * attributes, the returned map is empty.

     */

    public Map<String,?> getAttributes();

    /**

     * <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>

     *

     * @param env client connection parameters of the same sort that

     * can 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;

}