Add new MessagingOperations ifc and class hieararchy

spring-websocket/src/main/java/org/springframework/web/messaging/support/WebMessagingTemplate.java

@@ -0,0 +1,119 @@
+package org.springframework.web.messaging.support;
+
+import org.springframework.messaging.Message;
+import org.springframework.messaging.MessageChannel;
+import org.springframework.messaging.MessageDeliveryException;
+import org.springframework.messaging.converter.DefaultMessageConverter;
+import org.springframework.messaging.converter.MessageConverter;
+import org.springframework.messaging.core.MessagePostProcessor;
+import org.springframework.messaging.core.MessageSendingOperations;
+import org.springframework.messaging.support.MessageBuilder;
+import org.springframework.util.Assert;
+import org.springframework.web.messaging.MessageType;
+
+
+public class WebMessagingTemplate implements MessageSendingOperations<String> {
+
+	private final MessageChannel outputChannel;
+
+	protected volatile MessageConverter converter = new DefaultMessageConverter();
+
+	private volatile String defaultDestination;
+
+	private volatile long sendTimeout = -1;
+
+
+	public WebMessagingTemplate(MessageChannel outputChannel) {
+		Assert.notNull(outputChannel, "outputChannel is required");
+		this.outputChannel = outputChannel;
+	}
+
+
+	/**
+	 * Set the {@link MessageConverter} that is to be used to convert
+	 * between Messages and objects for this template.
+	 * <p>The default is {@link SimpleMessageConverter}.
+	 */
+	public void setMessageConverter(MessageConverter messageConverter) {
+		Assert.notNull(messageConverter, "'messageConverter' must not be null");
+		this.converter = messageConverter;
+	}
+
+	/**
+	 * Specify the timeout value to use for send operations.
+	 *
+	 * @param sendTimeout the send timeout in milliseconds
+	 */
+	public void setSendTimeout(long sendTimeout) {
+		this.sendTimeout = sendTimeout;
+	}
+
+	public void setDefaultDestination(String defaultDestination) {
+		this.defaultDestination = defaultDestination;
+	}
+
+
+	@Override
+	public <P> void send(Message<P> message) {
+		this.send(getRequiredDefaultDestination(), message);
+	}
+
+	private String getRequiredDefaultDestination() {
+
+		// TODO: maybe look up destination of current message (via ThreadLocal)
+
+		Assert.state(this.defaultDestination != null,
+				"No 'defaultDestination' specified for WebMessagingTemplate. " +
+				"Unable to invoke method without an explicit destination argument.");
+
+		return this.defaultDestination;
+	}
+
+	@Override
+	public <P> void send(String destinationName, Message<P> message) {
+		Assert.notNull(destinationName, "destinationName is required");
+		message = addDestinationToMessage(message, destinationName);
+		long timeout = this.sendTimeout;
+		boolean sent = (timeout >= 0)
+				? this.outputChannel.send(message, timeout)
+				: this.outputChannel.send(message);
+		if (!sent) {
+			throw new MessageDeliveryException(message,
+					"failed to send message to destination '" + destinationName + "' within timeout: " + timeout);
+		}
+	}
+
+	protected <P> Message<P> addDestinationToMessage(Message<P> message, String destinationName) {
+		Assert.notNull(destinationName, "destinationName is required");
+		WebMessageHeaderAccesssor headers = WebMessageHeaderAccesssor.create(MessageType.MESSAGE);
+		headers.copyHeaders(message.getHeaders());
+		headers.setDestination(destinationName);
+		message = MessageBuilder.withPayload(message.getPayload()).copyHeaders(headers.toMap()).build();
+		return message;
+	}
+
+	@Override
+	public <T> void convertAndSend(T object) {
+		this.convertAndSend(getRequiredDefaultDestination(), object);
+	}
+
+	@Override
+	public <T> void convertAndSend(String destinationName, T object) {
+		this.convertAndSend(destinationName, object, null);
+	}
+
+	@Override
+	public <T> void convertAndSend(T object, MessagePostProcessor postProcessor) {
+		this.convertAndSend(getRequiredDefaultDestination(), object, postProcessor);
+	}
+
+	@Override
+	public <T> void convertAndSend(String destinationName, T object, MessagePostProcessor postProcessor) {
+		Message<?> message = this.converter.toMessage(object);
+		if (postProcessor != null) {
+			message = postProcessor.postProcessMessage(message);
+		}
+		this.send(destinationName, message);
+	}
+
+}