cometd源码阅读-Listener监听器(十一)

文章主目录

接口定义
监听器实现

接口定义

java.util.EventListener

/**
 * A tagging interface that all event listener interfaces must extend.
 * @since JDK1.1
 */
public interface EventListener {
}

org.cometd.bayeux.Bayeux.BayeuxListener

    /**
     * <p>The common base interface for Bayeux listeners.</p>
     * <p>Specific sub-interfaces define what kind of events listeners will be notified.</p>
     */
    interface BayeuxListener extends EventListener {
    }

org.cometd.bayeux.Bayeux.BayeuxListener

    interface BayeuxServerListener extends BayeuxListener {
    }

回到顶部

^{监听器实现}

ChannelListener

使用

BayeuxServer bayeuxServer = ...;
bayeuxServer.addListener(new ChannelListener(){....});
bayeuxServer.addListener(new ChannelListener(){....});

接口定义

    public interface ChannelListener extends BayeuxServerListener, ConfigurableServerChannel.Initializer {
        /**
         * <p>Callback invoked when a {@link ServerChannel} has been added to a {@link BayeuxServer} object.</p>
         * <源码处>channel初始化成功
         * @param channel the channel that has been added
         */
        public default void channelAdded(ServerChannel channel) {
        }

        /**
         * <p>Callback invoked when a {@link ServerChannel} has been removed from a {@link BayeuxServer} object.</p>
         * <源码处>channel初始化移除成功
         * @param channelId the channel identifier of the channel that has been removed.
         */
        public default void channelRemoved(String channelId) {
        }
    }

SessionListener

使用

BayeuxServer bayeuxServer = ...;
bayeuxServer.addListener(new SessionListener(){....});
bayeuxServer.addListener(new SessionListener(){....});

接口定义

public interface SessionListener extends BayeuxServerListener {
        /**
         * <p>Callback invoked when a {@link ServerSession} has been added to a {@link BayeuxServer} object.</p>
         * <源码调用处>握手成功 内部session成功
         * @param session the session that has been added
         * @param message the handshake message from the client
         */
        public default void sessionAdded(ServerSession session, ServerMessage message) {
        }

        /**
         * <p>Callback invoked when a {@link ServerSession} has been removed from a {@link BayeuxServer} object.</p>
         *<源码调用处> session移除后监听回调 比如我们手动调用remove 或者超时自动剔除
         * @param session the session that has been removed
         * @param message the message that caused the session removal, or null
         * @param timeout whether the session has been removed due to a timeout 可以判断是否是超时剔除
         */
        public default void sessionRemoved(ServerSession session, ServerMessage message, boolean timeout) {
            sessionRemoved(session, timeout);
        }

        /**
         * <p>Callback invoked when a {@link ServerSession} has been removed from a {@link BayeuxServer} object.</p>
         *
         * @param session the session that has been removed
         * @param timeout whether the session has been removed for a timeout or not
         * @deprecated use {@link #sessionRemoved(ServerSession, ServerMessage, boolean)} instead
         */
        @Deprecated
        public default void sessionRemoved(ServerSession session, boolean timeout) {
        }
    }

SubscriptionListener

全局使用

BayeuxServer bayeuxServer = ...;
bayeuxServer.addListener(new SubsriptionListener(){....});
bayeuxServer.addListener(new SubscriptionListener(){....});

channel级利用ChannelListener全局监听器实现

      /**
         * <p>Callback invoked when a {@link ServerChannel} has been added to a {@link BayeuxServer} object.</p>
         * channel初始化成功
         * @param channel the channel that has been added
         */
        public void channelAdded(ServerChannel channel) {
            if(channel.isService()){
                channel.addListener(new ServerChannel.SubscriptionListener() {
                    @Override
                    public void subscribed(ServerSession session, ServerChannel channel, ServerMessage message) {

                    }

                    @Override
                    public void unsubscribed(ServerSession session, ServerChannel channel, ServerMessage message) {

                    }
                });
            }
        }

接口定义

  public interface SubscriptionListener extends BayeuxServerListener {
        /**
         * <p>Callback invoked when a {@link ServerSession} subscribes to a {@link ServerChannel}.</p>
         * <源码处>订阅指定渠道
         * @param session the session that subscribes
         * @param channel the channel to subscribe to
         * @param message the subscription message sent by the client, or null in case of
         *                server-side subscription via {@link ServerChannel#subscribe(ServerSession)}
         */
        public default void subscribed(ServerSession session, ServerChannel channel, ServerMessage message) {
        }

        /**
         * <p>Callback invoked when a {@link ServerSession} unsubscribes from a {@link ServerChannel}.</p>
         * <源码处>取消订阅指定渠道
         * @param session the session that unsubscribes
         * @param channel the channel to unsubscribe from
         * @param message the unsubscription message sent by the client, or null in case of
         *                server-side unsubscription via {@link ServerChannel#unsubscribe(ServerSession)}
         */
        public default void unsubscribed(ServerSession session, ServerChannel channel, ServerMessage message) {
        }
    }

MessageListener

 public interface MessageListener extends ServerChannelListener {
        /**
         * <p>Callback invoked when a message is being published.</p>
         * <p>Implementers can notify the promise with false to signal
         * that the message should not be published.</p>
         *
         * @param sender  the session that publishes the message
         * @param channel the channel the message is published to
         * @param message the message to be published
         * @param promise the promise to notify whether the message processing should continue
         */
        public default void onMessage(ServerSession sender, ServerChannel channel, ServerMessage.Mutable message, Promise<Boolean> promise) {
            promise.succeed(onMessage(sender, channel, message));
        }

        /**
         * <p>Blocking version of {@link #onMessage(ServerSession, ServerChannel, ServerMessage.Mutable, Promise)}.</p>
         *
         * @param sender  the session that publishes the message
         * @param channel the channel the message is published to
         * @param message the message to be published
         * @return whether the message processing should continue
         */
        public default boolean onMessage(ServerSession sender, ServerChannel channel, ServerMessage.Mutable message) {
            return true;
        }
    }