org.springframework.messaging.simp.handler.SimpleBrokerMessageHandler.java Source code

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Here is the source code for org.springframework.messaging.simp.handler.SimpleBrokerMessageHandler.java

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/*
 * Copyright 2002-2013 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.messaging.simp.handler;

import java.util.List;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.messaging.Message;
import org.springframework.messaging.MessageChannel;
import org.springframework.messaging.MessageHandler;
import org.springframework.messaging.MessagingException;
import org.springframework.messaging.simp.SimpMessageHeaderAccessor;
import org.springframework.messaging.simp.SimpMessageType;
import org.springframework.messaging.support.MessageBuilder;
import org.springframework.util.Assert;
import org.springframework.util.CollectionUtils;
import org.springframework.util.MultiValueMap;

/**
 * @author Rossen Stoyanchev
 * @since 4.0
 */
public class SimpleBrokerMessageHandler implements MessageHandler {

    private static final Log logger = LogFactory.getLog(SimpleBrokerMessageHandler.class);

    private final MessageChannel messageChannel;

    private List<String> destinationPrefixes;

    private SubscriptionRegistry subscriptionRegistry = new DefaultSubscriptionRegistry();

    /**
     * @param messageChannel the channel to broadcast messages to
     */
    public SimpleBrokerMessageHandler(MessageChannel messageChannel) {
        Assert.notNull(messageChannel, "messageChannel is required");
        this.messageChannel = messageChannel;
    }

    public void setDestinationPrefixes(List<String> destinationPrefixes) {
        this.destinationPrefixes = destinationPrefixes;
    }

    public List<String> getDestinationPrefixes() {
        return this.destinationPrefixes;
    }

    public void setSubscriptionRegistry(SubscriptionRegistry subscriptionRegistry) {
        Assert.notNull(subscriptionRegistry, "subscriptionRegistry is required");
        this.subscriptionRegistry = subscriptionRegistry;
    }

    public SubscriptionRegistry getSubscriptionRegistry() {
        return this.subscriptionRegistry;
    }

    @Override
    public void handleMessage(Message<?> message) throws MessagingException {

        SimpMessageHeaderAccessor headers = SimpMessageHeaderAccessor.wrap(message);
        SimpMessageType messageType = headers.getMessageType();
        String destination = headers.getDestination();

        if (!checkDestinationPrefix(destination)) {
            return;
        }

        if (SimpMessageType.SUBSCRIBE.equals(messageType)) {
            preProcessMessage(message);
            this.subscriptionRegistry.registerSubscription(message);
        } else if (SimpMessageType.UNSUBSCRIBE.equals(messageType)) {
            preProcessMessage(message);
            this.subscriptionRegistry.unregisterSubscription(message);
        } else if (SimpMessageType.MESSAGE.equals(messageType)) {
            preProcessMessage(message);
            sendMessageToSubscribers(headers.getDestination(), message);
        } else if (SimpMessageType.DISCONNECT.equals(messageType)) {
            preProcessMessage(message);
            String sessionId = SimpMessageHeaderAccessor.wrap(message).getSessionId();
            this.subscriptionRegistry.unregisterAllSubscriptions(sessionId);
        }
    }

    private boolean checkDestinationPrefix(String destination) {
        if ((destination == null) || CollectionUtils.isEmpty(this.destinationPrefixes)) {
            return true;
        }
        for (String prefix : this.destinationPrefixes) {
            if (destination.startsWith(prefix)) {
                return true;
            }
        }
        return false;
    }

    private void preProcessMessage(Message<?> message) {
        if (logger.isTraceEnabled()) {
            logger.trace("Processing " + message);
        }
    }

    protected void sendMessageToSubscribers(String destination, Message<?> message) {
        MultiValueMap<String, String> subscriptions = this.subscriptionRegistry.findSubscriptions(message);
        for (String sessionId : subscriptions.keySet()) {
            for (String subscriptionId : subscriptions.get(sessionId)) {

                SimpMessageHeaderAccessor headers = SimpMessageHeaderAccessor.wrap(message);
                headers.setSessionId(sessionId);
                headers.setSubscriptionId(subscriptionId);

                Object payload = message.getPayload();
                Message<?> clientMessage = MessageBuilder.withPayloadAndHeaders(payload, headers).build();
                try {
                    this.messageChannel.send(clientMessage);
                } catch (Throwable ex) {
                    logger.error("Failed to send message to destination=" + destination + ", sessionId=" + sessionId
                            + ", subscriptionId=" + subscriptionId, ex);
                }
            }
        }
    }
}