INT-4038: Add GPFB Gateways to Graph

JIRA: https://jira.spring.io/browse/INT-4038

General format for node name: bean.method#n

The #n is needed to disambiguate methods with the same name.

Polishing according PR comments

* Fix generic type for `Collections.unmodifiableMap` usage
* Change the gateway method logic in the `IntegrationGraphServer` to include the method signature in the node name to distinguish them as unique
* Move `MutableMessageBuilderFactoryTests` into the separate nested `mutable` package since `@IntegrationComponentScan` sees a new `@MessagingGateway` in the `IntegrationGraphServerTests`.
See https://jira.spring.io/browse/INT-4040
* Document the `@MessagingGateway` representation in the `graph.adoc`

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

@@ -20,6 +20,7 @@ import java.lang.reflect.Method;
 import java.lang.reflect.ParameterizedType;
 import java.lang.reflect.Type;
 import java.lang.reflect.UndeclaredThrowableException;
+import java.util.Collections;
 import java.util.HashMap;
 import java.util.Map;
 import java.util.concurrent.Callable;
@@ -279,6 +280,16 @@ public class GatewayProxyFactoryBean extends AbstractEndpoint
 		return this.asyncExecutor;
 	}
 
+	/**
+	 * Return the Map of {@link Method} to {@link MessagingGatewaySupport}
+	 * generated by this factory bean.
+	 * @return the map.
+	 * @since 4.3
+	 */
+	public Map<Method, MessagingGatewaySupport> getGateways() {
+		return Collections.<Method, MessagingGatewaySupport>unmodifiableMap(this.gatewayMap);
+	}
+
 	@Override
 	protected void onInit() {
 		synchronized (this.initializationMonitor) {
@@ -520,8 +531,8 @@ public class GatewayProxyFactoryBean extends AbstractEndpoint
 		if (StringUtils.hasText(payloadExpression)) {
 			messageMapper.setPayloadExpression(payloadExpression);
 		}
- 		messageMapper.setBeanFactory(this.getBeanFactory());
- 		MethodInvocationGateway gateway = new MethodInvocationGateway(messageMapper);
+		messageMapper.setBeanFactory(this.getBeanFactory());
+		MethodInvocationGateway gateway = new MethodInvocationGateway(messageMapper);
 		gateway.setErrorChannel(this.errorChannel);
 		if (this.getTaskScheduler() != null) {
 			gateway.setTaskScheduler(this.getTaskScheduler());
@@ -594,7 +605,7 @@ public class GatewayProxyFactoryBean extends AbstractEndpoint
 	private static boolean hasReturnParameterizedWithMessage(Method method, boolean runningOnCallerThread) {
 		if (!runningOnCallerThread &&
 				(Future.class.isAssignableFrom(method.getReturnType())
-				|| (reactorPresent && Promise.class.isAssignableFrom(method.getReturnType())))) {
+						|| (reactorPresent && Promise.class.isAssignableFrom(method.getReturnType())))) {
 			Type returnType = method.getGenericReturnType();
 			if (returnType instanceof ParameterizedType) {
 				Type[] typeArgs = ((ParameterizedType) returnType).getActualTypeArguments();

spring-integration-core/src/main/java/org/springframework/integration/support/management/graph/IntegrationGraphServer.java

@@ -16,6 +16,7 @@
 
 package org.springframework.integration.support.management.graph;
 
+import java.lang.reflect.Method;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.HashMap;
@@ -33,12 +34,14 @@ import org.springframework.integration.endpoint.IntegrationConsumer;
 import org.springframework.integration.endpoint.MessageProducerSupport;
 import org.springframework.integration.endpoint.PollingConsumer;
 import org.springframework.integration.endpoint.SourcePollingChannelAdapter;
+import org.springframework.integration.gateway.GatewayProxyFactoryBean;
 import org.springframework.integration.gateway.MessagingGatewaySupport;
 import org.springframework.integration.handler.CompositeMessageHandler;
 import org.springframework.integration.handler.DiscardingMessageHandler;
 import org.springframework.integration.support.context.NamedComponent;
 import org.springframework.messaging.MessageChannel;
 import org.springframework.messaging.MessageHandler;
+import org.springframework.util.StringUtils;
 
 /**
  * Builds the runtime object model graph.
@@ -162,6 +165,21 @@ public class IntegrationGraphServer implements ApplicationContextAware, Applicat
 			nodes.add(gatewayNode);
 			producerLink(links, channelNodes, gatewayNode);
 		}
+		Map<String, GatewayProxyFactoryBean> gpfbs = this.applicationContext
+				.getBeansOfType(GatewayProxyFactoryBean.class);
+		for (Entry<String, GatewayProxyFactoryBean> entry : gpfbs.entrySet()) {
+			Map<Method, MessagingGatewaySupport> methodMap = entry.getValue().getGateways();
+			for (Entry<Method, MessagingGatewaySupport> gwEntry : methodMap.entrySet()) {
+				MessagingGatewaySupport gateway = gwEntry.getValue();
+				Method method = gwEntry.getKey();
+				String signature = method.getName() +
+						"(" + StringUtils.arrayToCommaDelimitedString(method.getParameterTypes()) + ")";
+				MessageGatewayNode gatewayNode = this.nodeFactory.gatewayNode(
+						entry.getKey().substring(1) + "." + signature, gateway);
+				nodes.add(gatewayNode);
+				producerLink(links, channelNodes, gatewayNode);
+			}
+		}
 	}
 
 	private void producers(Collection<IntegrationNode> nodes, Collection<LinkNode> links,
@@ -258,12 +276,12 @@ public class IntegrationGraphServer implements ApplicationContextAware, Applicat
 			String outputChannelName = outputChannel == null ? null : outputChannel.toString();
 			MessageHandler handler = consumer.getHandler();
 			return handler instanceof CompositeMessageHandler
-				? compositeHandler(name, consumer, (CompositeMessageHandler) handler, outputChannelName, null, false)
-				: handler instanceof DiscardingMessageHandler
+					? compositeHandler(name, consumer, (CompositeMessageHandler) handler, outputChannelName, null, false)
+					: handler instanceof DiscardingMessageHandler
 					? discardingHandler(name, consumer, (DiscardingMessageHandler) handler, outputChannelName, null,
-							false)
+					false)
 					: new MessageHandlerNode(this.nodeId.incrementAndGet(), name, handler,
-						consumer.getInputChannel().toString(), outputChannelName);
+					consumer.getInputChannel().toString(), outputChannelName);
 		}
 
 		private MessageHandlerNode polledHandlerNode(String name, PollingConsumer consumer) {
@@ -273,13 +291,13 @@ public class IntegrationGraphServer implements ApplicationContextAware, Applicat
 					? consumer.getDefaultErrorChannel().toString() : null;
 			MessageHandler handler = consumer.getHandler();
 			return handler instanceof CompositeMessageHandler
-				? compositeHandler(name, consumer, (CompositeMessageHandler) handler, outputChannelName, errorChannel,
-						true)
-				:  handler instanceof DiscardingMessageHandler
+					? compositeHandler(name, consumer, (CompositeMessageHandler) handler, outputChannelName, errorChannel,
+					true)
+					: handler instanceof DiscardingMessageHandler
 					? discardingHandler(name, consumer, (DiscardingMessageHandler) handler, outputChannelName,
-							errorChannel, true)
+					errorChannel, true)
 					: new ErrorCapableMessageHandlerNode(this.nodeId.incrementAndGet(), name, handler,
-						consumer.getInputChannel().toString(), outputChannelName, errorChannel);
+					consumer.getInputChannel().toString(), outputChannelName, errorChannel);
 		}
 
 		private MessageHandlerNode compositeHandler(String name, IntegrationConsumer consumer,
@@ -295,19 +313,19 @@ public class IntegrationGraphServer implements ApplicationContextAware, Applicat
 				}
 			}
 			return polled
-				? new ErrorCapableCompositeMessageHandlerNode(this.nodeId.incrementAndGet(), name, handler,
-						consumer.getInputChannel().toString(), output, errors, innerHandlers)
-				: new CompositeMessageHandlerNode(this.nodeId.incrementAndGet(), name, handler,
-						consumer.getInputChannel().toString(), output, innerHandlers);
+					? new ErrorCapableCompositeMessageHandlerNode(this.nodeId.incrementAndGet(), name, handler,
+					consumer.getInputChannel().toString(), output, errors, innerHandlers)
+					: new CompositeMessageHandlerNode(this.nodeId.incrementAndGet(), name, handler,
+					consumer.getInputChannel().toString(), output, innerHandlers);
 		}
 
 		private MessageHandlerNode discardingHandler(String name, IntegrationConsumer consumer,
 				DiscardingMessageHandler handler, String output, String errors, boolean polled) {
 			return polled
-				? new ErrorCapableDiscardingMessageHandlerNode(this.nodeId.incrementAndGet(), name, handler,
-						consumer.getInputChannel().toString(), output, handler.getDiscardChannel().toString(), errors)
-				: new DiscardingMessageHandlerNode(this.nodeId.incrementAndGet(), name, handler,
-						consumer.getInputChannel().toString(), output, handler.getDiscardChannel().toString());
+					? new ErrorCapableDiscardingMessageHandlerNode(this.nodeId.incrementAndGet(), name, handler,
+					consumer.getInputChannel().toString(), output, handler.getDiscardChannel().toString(), errors)
+					: new DiscardingMessageHandlerNode(this.nodeId.incrementAndGet(), name, handler,
+					consumer.getInputChannel().toString(), output, handler.getDiscardChannel().toString());
 		}
 
 		private void reset() {

spring-integration-core/src/test/java/org/springframework/integration/support/management/graph/IntegrationGraphServerTests.java

@@ -32,6 +32,8 @@ import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.context.annotation.ImportResource;
+import org.springframework.integration.annotation.IntegrationComponentScan;
+import org.springframework.integration.annotation.MessagingGateway;
 import org.springframework.integration.annotation.ServiceActivator;
 import org.springframework.integration.channel.DirectChannel;
 import org.springframework.integration.channel.MessagePublishingErrorHandler;
@@ -80,16 +82,17 @@ public class IntegrationGraphServerTests {
 		@SuppressWarnings("unchecked")
 		List<Map<?, ?>> nodes = (List<Map<?, ?>>) map.get("nodes");
 		assertThat(nodes, is(notNullValue()));
-		assertThat(nodes.size(), is(equalTo(19)));
+		assertThat(nodes.size(), is(equalTo(22)));
 		@SuppressWarnings("unchecked")
 		List<Map<?, ?>> links = (List<Map<?, ?>>) map.get("links");
 		assertThat(links, is(notNullValue()));
-		assertThat(links.size(), is(equalTo(17)));
+		assertThat(links.size(), is(equalTo(20)));
 	}
 
 	@Configuration
 	@EnableIntegration
 	@EnableIntegrationManagement
+	@IntegrationComponentScan
 	@ImportResource("org/springframework/integration/support/management/graph/integration-graph-context.xml")
 	public static class Config {
 
@@ -186,4 +189,15 @@ public class IntegrationGraphServerTests {
 
 	}
 
+	@MessagingGateway(defaultRequestChannel = "four")
+	public interface Gate {
+
+		void foo(String foo);
+
+		void foo(Integer foo);
+
+		void bar(String bar);
+
+	}
+
 }

spring-integration-core/src/test/java/org/springframework/integration/support/mutable/MutableMessageBuilderFactoryTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2015-2016 the original author or authors.
+ * Copyright 2016 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.
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-package org.springframework.integration.support;
+package org.springframework.integration.support.mutable;
 
 import static org.junit.Assert.assertTrue;
 
@@ -35,6 +35,7 @@ import org.springframework.integration.annotation.MessagingGateway;
 import org.springframework.integration.annotation.ServiceActivator;
 import org.springframework.integration.channel.DirectChannel;
 import org.springframework.integration.config.EnableIntegration;
+import org.springframework.integration.support.MutableMessageBuilderFactory;
 import org.springframework.messaging.MessageHeaders;
 import org.springframework.messaging.handler.annotation.Payload;
 import org.springframework.test.context.ContextConfiguration;

src/reference/asciidoc/graph.adoc

@@ -118,6 +118,53 @@ Within the graph, Spring Integration components are represented using the `Integ
 For example the `ErrorCapableDiscardingMessageHandlerNode` could be used for the `AggregatingMessageHandler` (because it has a `discardChannel` option) and can produce errors when consuming from a `PollableChannel` using a `PollingConsumer`.
 Another sample is `CompositeMessageHandlerNode` - for a `MessageHandlerChain` when subscribed to a `SubscribableChannel`, using an `EventDrivenConsumer`.
 
+NOTE: The `@MessagingGateway` (see <<gateway>>) provides nodes for each its method, where the `name` attribute is based on the gateway's bean name and the short method signature.
+For example the gateway:
+
+[source,java]
+----
+@MessagingGateway(defaultRequestChannel = "four")
+public interface Gate {
+
+	void foo(String foo);
+
+	void foo(Integer foo);
+
+	void bar(String bar);
+
+}
+----
+
+produces nodes like:
+[source,json]
+
+----
+{
+  "nodeId" : 10,
+  "name" : "gate.bar(class java.lang.String)",
+  "stats" : null,
+  "componentType" : "gateway",
+  "output" : "four",
+  "errors" : null
+},
+{
+  "nodeId" : 11,
+  "name" : "gate.foo(class java.lang.String)",
+  "stats" : null,
+  "componentType" : "gateway",
+  "output" : "four",
+  "errors" : null
+},
+{
+  "nodeId" : 12,
+  "name" : "gate.foo(class java.lang.Integer)",
+  "stats" : null,
+  "componentType" : "gateway",
+  "output" : "four",
+  "errors" : null
+}
+----
+
 This  `IntegrationNode` hierarchy can be used for parsing the graph model on the client side, as well as for the understanding the general Spring Integration runtime behavior.
 See also <<programming-tips>> for more information.
 
@@ -133,7 +180,7 @@ The `IntegrationGraphController` `@RestController` provides these services:
 - `@GetMapping(name = "getGraph")` - to retrieve the state of the Spring Integration components since the last `IntegrationGraphServer` refresh.
 The `o.s.i.support.management.graph.Graph` is returned as a `@ResponseBody` of the REST service;
 - `@GetMapping(path = "/refresh", name = "refreshGraph")` - to refresh the current `Graph` for the actual runtime state and return it as a REST response.
-It is not necessaery to refresh the graph for metrics, they are provided in real-time when the graph is retrieved.
+It is not necessary to refresh the graph for metrics, they are provided in real-time when the graph is retrieved.
 Refresh can be called if the application context has been modified since the graph was last retrieved and the graph is completely rebuilt.
 
 Any Security and Cross Origin restrictions for the `IntegrationGraphController` can be achieved with the standard configuration options and components provided by Spring Security and Spring MVC projects.