jmsconnection.java

来自「OpenJMS是一个开源的Java Message Service API 1.」· Java 代码 · 共 643 行 · 第 1/2 页

                    session.start();
                }
                // set the state of the connection to start
                _stopped = false;
            }
        } catch (JMSException exception) {
            // do we need to change _stopped to true if the any of the
            // sessions fail to start
            throw exception;
        }
    }

    /**
     * Temporarily stops a connection's delivery of incoming messages. Delivery
     * can be restarted using the connection's <code>start</code> method. When
     * the connection is stopped, delivery to all the connection's message
     * consumers is inhibited: synchronous receives block, and messages are not
     * delivered to message listeners.
     * <p/>
     * <P>This call blocks until receives and/or message listeners in progress
     * have completed.
     * <p/>
     * <P>Stopping a connection has no effect on its ability to send messages. A
     * call to <code>stop</code> on a connection that has already been stopped
     * is ignored.
     *
     * @throws JMSException if the JMS provider fails to stop message delivery
     *                      due to some internal error.
     */
    public synchronized void stop() throws JMSException {
        ensureOpen();
        setModified();

        if (!_stopped) {
            // stop the associated sessions
            synchronized (_sessions) {
                Iterator iterator = _sessions.iterator();
                while (iterator.hasNext()) {
                    JmsSession session = (JmsSession) iterator.next();
                    session.stop();
                }
            }
            // set the state of the connection to stopped
            _stopped = true;
        }
    }

    /**
     * Closes the connection.
     * <P>When this method is invoked, it should not return until message
     * processing has been shut down in an orderly fashion. This means that all
     * message listeners that may have been running have returned, and that all
     * pending receives have returned. A close terminates all pending message
     * receives on the connection's sessions' consumers. The receives may return
     * with a message or with null, depending on whether there was a message
     * available at the time of the close. If one or more of the connection's
     * sessions' message listeners is processing a message at the time when
     * connection <code>close</code> is invoked, all the facilities of the
     * connection and its sessions must remain available to those listeners
     * until they return control to the JMS provider.
     * <p/>
     * <P>Closing a connection causes any of its sessions' transactions in
     * progress to be rolled back. In the case where a session's work is
     * coordinated by an external transaction manager, a session's
     * <code>commit</code> and <code>rollback</code> methods are not used and
     * the result of a closed session's work is determined later by the
     * transaction manager.
     * <p/>
     * Closing a connection does NOT force an acknowledgment of
     * client-acknowledged sessions.
     * <p/>
     * <P>Invoking the <code>acknowledge</code> method of a received message
     * from a closed connection's session must throw an
     * <code>IllegalStateException</code>.
     * Closing a closed connection must NOT throw an exception.
     *
     * @throws JMSException if the JMS provider fails to close the connection
     *                      due to some internal error.
     */
    public synchronized void close() throws JMSException {
        if (!_closed) {
            // before we close we should stop the connection and any
            // associated sessions
            stop();

            // close the sessions
            JmsSession[] sessions = null;
            synchronized (_sessions) {
                sessions = (JmsSession[]) _sessions.toArray(new JmsSession[0]);
            }
            for (int i = 0; i < sessions.length; ++i) {
                sessions[i].close();
                // the session deregisters itself with the connection via
                // removeSession()
            }

            // notify the server, and null the proxy
            getServerConnection().close();
            _connection = null;

            // remove this from the list of connections managed by the
            // connection factory and then null the factory.
            _factory.removeConnection(this);
            _factory = null;

            // set the closed flag so calling it multiple times is
            // cool
            _closed = true;
        }
    }

    /**
     * Creates a <code>Session</code> object.
     *
     * @param transacted      indicates whether the session is transacted
     * @param acknowledgeMode indicates whether the consumer or the client will
     *                        acknowledge any messages it receives; ignored if
     *                        the session is transacted. Legal values are
     *                        <code>Session.AUTO_ACKNOWLEDGE</code>,
     *                        <code>Session.CLIENT_ACKNOWLEDGE</code>, and
     *                        <code>Session.DUPS_OK_ACKNOWLEDGE</code>.
     * @return a newly created session
     * @throws JMSException if the <code>Connection</code> object fails to
     *                      create a session due to some internal error or lack
     *                      of support for the specific transaction and
     *                      acknowledgement mode.
     * @see Session#AUTO_ACKNOWLEDGE
     * @see Session#CLIENT_ACKNOWLEDGE
     * @see Session#DUPS_OK_ACKNOWLEDGE
     */
    public Session createSession(boolean transacted, int acknowledgeMode)
            throws JMSException {
        ensureOpen();
        setModified();

        JmsSession session = new JmsSession(this, transacted, acknowledgeMode);

        // if the connection is started then also start the session
        if (!isStopped()) {
            session.start();
        }

        // add it to the list of managed sessions for this connection
        addSession(session);

        return session;
    }

    /**
     * Creates a connection consumer for this connection (optional operation).
     * This is an expert facility not used by regular JMS clients.
     *
     * @param destination     the destination to access
     * @param messageSelector only messages with properties matching the message
     *                        selector expression are delivered.  A value of
     *                        null or an empty string indicates that there is no
     *                        message selector for the message consumer.
     * @param sessionPool     the server session pool to associate with this
     *                        connection consumer
     * @param maxMessages     the maximum number of messages that can be
     *                        assigned to a server session at one time
     * @return the connection consumer
     * @throws JMSException    if the <code>Connection</code> object fails to
     *                         create a connection consumer due to some internal
     *                         error or invalid arguments for
     *                         <code>sessionPool</code> and
     *                         <code>messageSelector</code>.
     * @throws InvalidDestinationException if an invalid destination is
     *                                     specified.
     * @throws InvalidSelectorException    if the message selector is invalid.
     */
    public ConnectionConsumer createConnectionConsumer(
            Destination destination, String messageSelector,
            ServerSessionPool sessionPool, int maxMessages)
            throws JMSException {
        ensureOpen();
        setModified();
        return new JmsConnectionConsumer(this, destination, sessionPool,
                                         messageSelector, maxMessages);
    }

    /**
     * Create a durable connection consumer for this connection.
     *
     * @param topic            topic to access
     * @param subscriptionName durable subscription name
     * @param messageSelector  only messages with properties matching the
     *                         message selector expression are delivered.  A
     *                         value of null or an empty string indicates that
     *                         there is no message selector for the message
     *                         consumer.
     * @param sessionPool      the server session pool to associate with this
     *                         durable connection consumer
     * @param maxMessages      the maximum number of messages that can be
     *                         assigned to a server session at one time
     * @return the durable connection consumer
     * @throws JMSException    if the <code>Connection</code> object fails to
     *                         create a connection consumer due to some internal
     *                         error or invalid arguments for
     *                         <code>sessionPool</code> and
     *                         <code>messageSelector</code>.
     * @throws InvalidDestinationException if an invalid destination is
     *                                     specified.
     * @throws InvalidSelectorException    if the message selector is invalid.
     */
    public ConnectionConsumer createDurableConnectionConsumer(
            Topic topic, String subscriptionName, String messageSelector,
            ServerSessionPool sessionPool, int maxMessages)
            throws JMSException {
        ensureOpen();
        setModified();
        return new JmsConnectionConsumer(this, topic, subscriptionName,
                                         sessionPool, messageSelector,
                                         maxMessages);
    }

    /**
     * Returns the server connection.
     *
     * @return the server connection
     * @throws JMSException if the connection is <code>null</code>
     */
    protected ServerConnection getServerConnection() throws JMSException {
        if (_connection == null) {
            throw new JMSException("Connection closed");
        }

        return _connection;
    }

    /**
     * Add the specified session to the list of managed sessions.
     *
     * @param session session to register
     */
    protected void addSession(JmsSession session) {
        synchronized (_sessions) {
            _sessions.add(session);
        }
    }

    /**
     * Remove the specified session from the list of managed sessions. If it
     * doesn't exist then fail silently.
     *
     * @param session session to remove
     */
    protected void removeSession(JmsSession session) {
        synchronized (_sessions) {
            _sessions.remove(session);
        }
    }

    /**
     * Returns the running state of the connection.
     *
     * @return <code>true</code> if stopped
     */
    protected boolean isStopped() {
        return _stopped;
    }

    /**
     * Flags this connection as being modified. Subsequent attempts to invoke
     * {@link #setClientID} will result in an <code>IllegalStateException</code>
     * being thrown.
     */
    protected void setModified() {
        _modified = true;
    }

    /**
     * Delete the temporary destination and all the registered sessions
     * consumers waiting to receive messages from this destination will be
     * stopped.
     * <p/>
     * It will throw a JMSException if the specified destination is not
     * temporary or if the destination is null or if the destination is not
     * owned by this connection
     *
     * @param destination temporary destination to delete
     * @throws JMSException
     */
    protected synchronized void deleteTemporaryDestination(
            JmsDestination destination)
            throws JMSException {
        if ((destination != null) &&
                (destination instanceof JmsTemporaryDestination)) {
            JmsTemporaryDestination temp_dest =
                    (JmsTemporaryDestination) destination;

            // check to see that this destination was actually created by
            // this connection
            if (temp_dest.getOwningConnection() == this) {
                // this is currently a no-op but we probably need a way to
                // clean up on the server side
            } else {
                throw new JMSException(
                        "The temp destination cannot be used outside the scope "
                        + "of the connection creating it");
            }
        } else {
            throw new JMSException("The destination is not temporary");
        }
    }

    /**
     * Verifies that the connection is open.
     *
     * @throws IllegalStateException if the connection is closed
     */
    protected void ensureOpen() throws IllegalStateException {
        if (_closed) {
            throw new IllegalStateException(
                    "Cannot perform operation - session has been closed");
        }
    }

}