spring SimpMessagingTemplate 源码

spring SimpMessagingTemplate 代码

文件路径：/spring-messaging/src/main/java/org/springframework/messaging/simp/SimpMessagingTemplate.java

/*
 * Copyright 2002-2019 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
 *
 *      https://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;

import java.util.Map;

import org.springframework.lang.Nullable;
import org.springframework.messaging.Message;
import org.springframework.messaging.MessageChannel;
import org.springframework.messaging.MessageDeliveryException;
import org.springframework.messaging.MessageHeaders;
import org.springframework.messaging.MessagingException;
import org.springframework.messaging.core.AbstractMessageSendingTemplate;
import org.springframework.messaging.core.MessagePostProcessor;
import org.springframework.messaging.support.MessageBuilder;
import org.springframework.messaging.support.MessageHeaderAccessor;
import org.springframework.messaging.support.MessageHeaderInitializer;
import org.springframework.messaging.support.NativeMessageHeaderAccessor;
import org.springframework.util.Assert;
import org.springframework.util.StringUtils;

/**
 * An implementation of
 * {@link org.springframework.messaging.simp.SimpMessageSendingOperations}.
 *
 * <p>Also provides methods for sending messages to a user. See
 * {@link org.springframework.messaging.simp.user.UserDestinationResolver
 * UserDestinationResolver}
 * for more on user destinations.
 *
 * @author Rossen Stoyanchev
 * @since 4.0
 */
public class SimpMessagingTemplate extends AbstractMessageSendingTemplate<String>
		implements SimpMessageSendingOperations {

	private final MessageChannel messageChannel;

	private String destinationPrefix = "/user/";

	private volatile long sendTimeout = -1;

	@Nullable
	private MessageHeaderInitializer headerInitializer;


	/**
	 * Create a new {@link SimpMessagingTemplate} instance.
	 * @param messageChannel the message channel (never {@code null})
	 */
	public SimpMessagingTemplate(MessageChannel messageChannel) {
		Assert.notNull(messageChannel, "MessageChannel must not be null");
		this.messageChannel = messageChannel;
	}


	/**
	 * Return the configured message channel.
	 */
	public MessageChannel getMessageChannel() {
		return this.messageChannel;
	}

	/**
	 * Configure the prefix to use for destinations targeting a specific user.
	 * <p>The default value is "/user/".
	 * @see org.springframework.messaging.simp.user.UserDestinationMessageHandler
	 */
	public void setUserDestinationPrefix(String prefix) {
		Assert.hasText(prefix, "User destination prefix must not be empty");
		this.destinationPrefix = (prefix.endsWith("/") ? prefix : prefix + "/");

	}

	/**
	 * Return the configured user destination prefix.
	 */
	public String getUserDestinationPrefix() {
		return this.destinationPrefix;
	}

	/**
	 * Specify the timeout value to use for send operations (in milliseconds).
	 */
	public void setSendTimeout(long sendTimeout) {
		this.sendTimeout = sendTimeout;
	}

	/**
	 * Return the configured send timeout (in milliseconds).
	 */
	public long getSendTimeout() {
		return this.sendTimeout;
	}

	/**
	 * Configure a {@link MessageHeaderInitializer} to apply to the headers of all
	 * messages created through the {@code SimpMessagingTemplate}.
	 * <p>By default, this property is not set.
	 */
	public void setHeaderInitializer(@Nullable MessageHeaderInitializer headerInitializer) {
		this.headerInitializer = headerInitializer;
	}

	/**
	 * Return the configured header initializer.
	 */
	@Nullable
	public MessageHeaderInitializer getHeaderInitializer() {
		return this.headerInitializer;
	}


	/**
	 * If the headers of the given message already contain a
	 * {@link org.springframework.messaging.simp.SimpMessageHeaderAccessor#DESTINATION_HEADER
	 * SimpMessageHeaderAccessor#DESTINATION_HEADER} then the message is sent without
	 * further changes.
	 * <p>If a destination header is not already present ,the message is sent
	 * to the configured {@link #setDefaultDestination(Object) defaultDestination}
	 * or an exception an {@code IllegalStateException} is raised if that isn't
	 * configured.
	 * @param message the message to send (never {@code null})
	 */
	@Override
	public void send(Message<?> message) {
		Assert.notNull(message, "Message is required");
		String destination = SimpMessageHeaderAccessor.getDestination(message.getHeaders());
		if (destination != null) {
			sendInternal(message);
			return;
		}
		doSend(getRequiredDefaultDestination(), message);
	}

	@Override
	protected void doSend(String destination, Message<?> message) {
		Assert.notNull(destination, "Destination must not be null");

		SimpMessageHeaderAccessor simpAccessor =
				MessageHeaderAccessor.getAccessor(message, SimpMessageHeaderAccessor.class);

		if (simpAccessor != null) {
			if (simpAccessor.isMutable()) {
				simpAccessor.setDestination(destination);
				simpAccessor.setMessageTypeIfNotSet(SimpMessageType.MESSAGE);
				simpAccessor.setImmutable();
				sendInternal(message);
				return;
			}
			else {
				// Try and keep the original accessor type
				simpAccessor = (SimpMessageHeaderAccessor) MessageHeaderAccessor.getMutableAccessor(message);
				initHeaders(simpAccessor);
			}
		}
		else {
			simpAccessor = SimpMessageHeaderAccessor.wrap(message);
			initHeaders(simpAccessor);
		}

		simpAccessor.setDestination(destination);
		simpAccessor.setMessageTypeIfNotSet(SimpMessageType.MESSAGE);
		message = MessageBuilder.createMessage(message.getPayload(), simpAccessor.getMessageHeaders());
		sendInternal(message);
	}

	private void sendInternal(Message<?> message) {
		String destination = SimpMessageHeaderAccessor.getDestination(message.getHeaders());
		Assert.notNull(destination, "Destination header required");

		long timeout = this.sendTimeout;
		boolean sent = (timeout >= 0 ? this.messageChannel.send(message, timeout) : this.messageChannel.send(message));

		if (!sent) {
			throw new MessageDeliveryException(message,
					"Failed to send message to destination '" + destination + "' within timeout: " + timeout);
		}
	}

	private void initHeaders(SimpMessageHeaderAccessor simpAccessor) {
		if (getHeaderInitializer() != null) {
			getHeaderInitializer().initHeaders(simpAccessor);
		}
	}


	@Override
	public void convertAndSendToUser(String user, String destination, Object payload) throws MessagingException {
		convertAndSendToUser(user, destination, payload, (MessagePostProcessor) null);
	}

	@Override
	public void convertAndSendToUser(String user, String destination, Object payload,
			@Nullable Map<String, Object> headers) throws MessagingException {

		convertAndSendToUser(user, destination, payload, headers, null);
	}

	@Override
	public void convertAndSendToUser(String user, String destination, Object payload,
			@Nullable MessagePostProcessor postProcessor) throws MessagingException {

		convertAndSendToUser(user, destination, payload, null, postProcessor);
	}

	@Override
	public void convertAndSendToUser(String user, String destination, Object payload,
			@Nullable Map<String, Object> headers, @Nullable MessagePostProcessor postProcessor)
			throws MessagingException {

		Assert.notNull(user, "User must not be null");
		Assert.isTrue(!user.contains("%2F"), "Invalid sequence \"%2F\" in user name: " + user);
		user = StringUtils.replace(user, "/", "%2F");
		destination = destination.startsWith("/") ? destination : "/" + destination;
		super.convertAndSend(this.destinationPrefix + user + destination, payload, headers, postProcessor);
	}


	/**
	 * Creates a new map and puts the given headers under the key
	 * {@link NativeMessageHeaderAccessor#NATIVE_HEADERS NATIVE_HEADERS NATIVE_HEADERS NATIVE_HEADERS}.
	 * effectively treats the input header map as headers to be sent out to the
	 * destination.
	 * <p>However if the given headers already contain the key
	 * {@code NATIVE_HEADERS NATIVE_HEADERS} then the same headers instance is
	 * returned without changes.
	 * <p>Also if the given headers were prepared and obtained with
	 * {@link SimpMessageHeaderAccessor#getMessageHeaders()} then the same headers
	 * instance is also returned without changes.
	 */
	@Override
	protected Map<String, Object> processHeadersToSend(@Nullable Map<String, Object> headers) {
		if (headers == null) {
			SimpMessageHeaderAccessor headerAccessor = SimpMessageHeaderAccessor.create(SimpMessageType.MESSAGE);
			initHeaders(headerAccessor);
			headerAccessor.setLeaveMutable(true);
			return headerAccessor.getMessageHeaders();
		}
		if (headers.containsKey(NativeMessageHeaderAccessor.NATIVE_HEADERS)) {
			return headers;
		}
		if (headers instanceof MessageHeaders) {
			SimpMessageHeaderAccessor accessor =
					MessageHeaderAccessor.getAccessor((MessageHeaders) headers, SimpMessageHeaderAccessor.class);
			if (accessor != null) {
				return headers;
			}
		}

		SimpMessageHeaderAccessor headerAccessor = SimpMessageHeaderAccessor.create(SimpMessageType.MESSAGE);
		initHeaders(headerAccessor);
		headers.forEach((key, value) -> headerAccessor.setNativeHeader(key, (value != null ? value.toString() : null)));
		return headerAccessor.getMessageHeaders();
	}

}

相关信息

spring 源码目录

相关文章

spring SimpAttributes 源码

spring SimpAttributesContextHolder 源码

spring SimpLogging 源码

spring SimpMessageHeaderAccessor 源码

spring SimpMessageMappingInfo 源码

spring SimpMessageSendingOperations 源码

spring SimpMessageType 源码

spring SimpMessageTypeMessageCondition 源码

spring SimpSessionScope 源码

spring package-info 源码