INT-1384 removed the recently added (yesterday) "requiresReply" Message header, but added the "requires-reply" attribute on the <service-activator> element

spring-integration-core/src/main/java/org/springframework/integration/MessageHeaders.java

@@ -58,8 +58,6 @@ public final class MessageHeaders implements Map<String, Object>, Serializable {
 
 	public static final String CORRELATION_ID = PREFIX + "correlationId";
 
-	public static final String REQUIRES_REPLY = PREFIX + "requiresReply";
-
 	public static final String REPLY_CHANNEL = PREFIX + "replyChannel";
 
 	public static final String ERROR_CHANNEL = PREFIX + "errorChannel";
@@ -100,11 +98,6 @@ public final class MessageHeaders implements Map<String, Object>, Serializable {
 		return this.get(REPLY_CHANNEL);
 	}
 
-	public boolean getRequiresReply() {
-		Boolean headerValue = this.get(REQUIRES_REPLY, Boolean.class);
-		return (headerValue != null && headerValue);
-	}
-
 	public Object getErrorChannel() {
 		return this.get(ERROR_CHANNEL);
 	}

spring-integration-core/src/main/java/org/springframework/integration/config/ServiceActivatorFactoryBean.java

@@ -32,10 +32,16 @@ public class ServiceActivatorFactoryBean extends AbstractMessageHandlerFactoryBe
 
 	private volatile Long sendTimeout;
 
+	private volatile Boolean requiresReply;
+
 	public void setSendTimeout(Long sendTimeout) {
 		this.sendTimeout = sendTimeout;
 	}
 
+	public void setRequiresReply(Boolean requiresReply) {
+		this.requiresReply = requiresReply;
+	}
+
 	@Override
 	MessageHandler createMethodInvokingHandler(Object targetObject, String targetMethodName) {
 		ServiceActivatingHandler handler = (StringUtils.hasText(targetMethodName))
@@ -58,7 +64,10 @@ public class ServiceActivatorFactoryBean extends AbstractMessageHandlerFactoryBe
 
 	private ServiceActivatingHandler configureHandler(ServiceActivatingHandler handler) {
 		if (this.sendTimeout != null) {
-			handler.setSendTimeout(sendTimeout);
+			handler.setSendTimeout(this.sendTimeout);
+		}
+		if (this.requiresReply != null) {
+			handler.setRequiresReply(this.requiresReply);
 		}
 		return handler;
 	}

spring-integration-core/src/main/java/org/springframework/integration/config/xml/AbstractDelegatingConsumerEndpointParser.java

@@ -83,6 +83,7 @@ abstract class AbstractDelegatingConsumerEndpointParser extends AbstractConsumer
 						"a 'ref' or inner-bean definition is provided.", element);
 			}
 		}
+		IntegrationNamespaceUtils.setValueIfAttributeDefined(builder, element, "requires-reply");
 		IntegrationNamespaceUtils.setValueIfAttributeDefined(builder, element, "send-timeout");
 		this.postProcess(builder, element, parserContext);
 		return builder;

spring-integration-core/src/main/java/org/springframework/integration/core/MessageBuilder.java

@@ -167,10 +167,6 @@ public final class MessageBuilder<T> {
 		return this.setHeader(MessageHeaders.CORRELATION_ID, correlationId);
 	}
 
-	public MessageBuilder<T> setRequiresReply(Boolean requiresReply) {
-		return this.setHeader(MessageHeaders.REQUIRES_REPLY, requiresReply);
-	}
-
 	public MessageBuilder<T> setReplyChannel(MessageChannel replyChannel) {
 		return this.setHeader(MessageHeaders.REPLY_CHANNEL, replyChannel);
 	}

spring-integration-core/src/main/java/org/springframework/integration/gateway/GatewayMethodInboundMessageMapper.java

@@ -202,9 +202,6 @@ class GatewayMethodInboundMessageMapper implements InboundMessageMapper<Object[]
 			}
 			builder.copyHeaders(evaluatedHeaders);
 		}
-		if (!void.class.equals(this.method.getReturnType())) {
-			builder.setRequiresReply(true);
-		}
 		return builder.build();
 	}
 

spring-integration-core/src/main/java/org/springframework/integration/handler/AbstractReplyProducingMessageHandler.java

@@ -104,22 +104,17 @@ public abstract class AbstractReplyProducingMessageHandler extends AbstractMessa
 	@Override
 	protected final void handleMessageInternal(Message<?> message) {
 		Object result = this.handleRequestMessage(message);
-		if (result == null) {
-			if (this.requiresReply) {
-				throw new MessageHandlingException(message, "handler '" + this
-						+ "' requires a reply, but no reply was received");
-			}
-			if (message != null && message.getHeaders().getRequiresReply()) {
-				throw new MessageHandlingException(message,
-						"A reply Message is required by this request Message, but none was received.");
-			}
-			if (logger.isDebugEnabled()) {
-				logger.debug("handler '" + this + "' produced no reply for request Message: " + message);
-			}
-			return;
+		if (result != null) {
+			MessageHeaders requestHeaders = message.getHeaders();
+			this.handleResult(result, requestHeaders);
+		}
+		else if (this.requiresReply) {
+			throw new MessageHandlingException(message, "handler '" + this
+					+ "' requires a reply, but no reply was received");
+		}
+		else if (logger.isDebugEnabled()) {
+			logger.debug("handler '" + this + "' produced no reply for request Message: " + message);
 		}
-		MessageHeaders requestHeaders = message.getHeaders();
-		this.handleResult(result, requestHeaders);
 	}
 
 	protected void handleResult(Object result, MessageHeaders requestHeaders) {

spring-integration-core/src/main/resources/org/springframework/integration/config/xml/spring-integration-2.0.xsd

@@ -798,6 +798,15 @@
 			<xsd:complexContent>
 				<xsd:extension base="expressionOrInnerEndpointDefinitionAware">
 					<xsd:attributeGroup ref="inputOutputChannelGroup" />
+					<xsd:attribute name="requires-reply" type="xsd:string" use="optional">
+						<xsd:annotation>
+							<xsd:documentation>
+	Specify whether the service method must return a non-null value. This value will be
+	FALSE by default, but if set to TRUE, a MessageHandlingException will be thrown when
+	the underlying service method (or expression) returns a NULL value.
+							</xsd:documentation>
+						</xsd:annotation>
+					</xsd:attribute>
 				</xsd:extension>
 			</xsd:complexContent>
 		</xsd:complexType>

spring-integration-core/src/test/java/org/springframework/integration/gateway/GatewayRequiresReplyTests-context.xml

@@ -12,6 +12,8 @@
 			 default-reply-timeout="3000"
 			 service-interface="org.springframework.integration.gateway.GatewayRequiresReplyTests$TestService" />
 
-	<service-activator input-channel="requestChannel" expression="payload == 'foo' ? 'bar' : null"/>
+	<service-activator input-channel="requestChannel"
+					   expression="payload == 'foo' ? 'bar' : null"
+					   requires-reply="true"/>
 
 </beans:beans>