INT-3664: Rework BPP in the IntMBExporter

JIRA: https://jira.spring.io/browse/INT-3664

Since all metrics are already direct for the integration components, we don't do any proxying from `IntegrationMBeanExporter`,
and even any other adjustments during BPP phases. Hence this stuff is already redundant for `IntegrationMBeanExporter`.
In addition this change fix the `early access to the BeanFactory from BPP` issue.

INT-3664: Address PR comments

Doc Polish

INT-3664: Polishing according the SF changes to the `PostProcessorRegistrationDelegate$BeanPostProcessorChecker`

spring-integration-jmx/src/test/java/org/springframework/integration/monitor/MBeanExporterIntegrationTests.java

@@ -190,6 +190,15 @@ public class MBeanExporterIntegrationTests {
 		}
 		// Lifecycle method name
 		assertEquals("start", startName);
+
+		context.close();
+
+		context = new GenericXmlApplicationContext(getClass(), "lifecycle-no-source.xml");
+		server = context.getBean(MBeanServer.class);
+		names = server.queryNames(ObjectName.getInstance("org.springframework.integration:type=ManagedEndpoint,*"), null);
+		assertEquals(1, names.size());
+		names = server.queryNames(ObjectName.getInstance("org.springframework.integration:name=gateway,*"), null);
+		assertEquals(1, names.size());
 	}
 
 	@Test

spring-integration-jmx/src/test/java/org/springframework/integration/monitor/MessageMetricsAdviceTests.java

@@ -10,6 +10,7 @@
  * 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.integration.monitor;
 
 import org.aopalliance.intercept.MethodInterceptor;
@@ -19,9 +20,11 @@ import org.junit.Test;
 
 import org.springframework.aop.framework.ProxyFactory;
 import org.springframework.aop.support.NameMatchMethodPointcutAdvisor;
-import org.springframework.beans.factory.support.DefaultListableBeanFactory;
+import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
+import org.springframework.context.support.GenericApplicationContext;
 import org.springframework.integration.channel.NullChannel;
 import org.springframework.integration.support.MessageBuilder;
+import org.springframework.integration.test.util.TestUtils;
 import org.springframework.messaging.Message;
 import org.springframework.messaging.MessageChannel;
 import org.springframework.messaging.MessageHandler;
@@ -32,10 +35,13 @@ import org.springframework.util.ClassUtils;
  * @author Tareq Abedrabbo
  * @author Dave Syer
  * @author Gary Russell
+ * @author Artem Bilan
  * @since 2.0.4
  */
 public class MessageMetricsAdviceTests {
 
+	private ConfigurableListableBeanFactory beanFactory;
+
 	private IntegrationMBeanExporter mBeanExporter;
 
 	private MessageHandler handler;
@@ -44,12 +50,16 @@ public class MessageMetricsAdviceTests {
 
 	@Before
 	public void setUp() throws Exception {
-		channel = new NullChannel();
-		mBeanExporter = new IntegrationMBeanExporter();
-		mBeanExporter.setBeanFactory(new DefaultListableBeanFactory());
-		mBeanExporter.setBeanClassLoader(ClassUtils.getDefaultClassLoader());
-		mBeanExporter.afterPropertiesSet();
-		handler = new DummyHandler();
+		GenericApplicationContext applicationContext = TestUtils.createTestApplicationContext();
+		this.beanFactory = applicationContext.getBeanFactory();
+		this.channel = new NullChannel();
+		this.mBeanExporter = new IntegrationMBeanExporter();
+		this.mBeanExporter.setApplicationContext(applicationContext);
+		this.mBeanExporter.setBeanFactory(this.beanFactory);
+		this.mBeanExporter.setBeanClassLoader(ClassUtils.getDefaultClassLoader());
+		this.mBeanExporter.afterPropertiesSet();
+		this.handler = new DummyHandler();
+		applicationContext.refresh();
 	}
 
 	@Test
@@ -59,11 +69,15 @@ public class MessageMetricsAdviceTests {
 		NameMatchMethodPointcutAdvisor advisor = new NameMatchMethodPointcutAdvisor(interceptor);
 		advisor.addMethodName("handleMessage");
 
-		ProxyFactory factory = new ProxyFactory(handler);
+		ProxyFactory factory = new ProxyFactory(this.handler);
 		factory.addAdvisor(advisor);
 		MessageHandler advised = (MessageHandler) factory.getProxy();
 
-		MessageHandler exported = (MessageHandler) mBeanExporter.postProcessAfterInitialization(advised, "test");
+		this.beanFactory.registerSingleton("test", advised);
+		this.beanFactory.initializeBean(advised, "test");
+
+		mBeanExporter.afterSingletonsInstantiated();
+		MessageHandler exported = this.beanFactory.getBean("test", MessageHandler.class);
 		exported.handleMessage(MessageBuilder.withPayload("test").build());
 	}
 
@@ -78,7 +92,11 @@ public class MessageMetricsAdviceTests {
 		factory.addAdvisor(advisor);
 		MessageChannel advised = (MessageChannel) factory.getProxy();
 
-		MessageChannel exported = (MessageChannel) mBeanExporter.postProcessAfterInitialization(advised, "test");
+		this.beanFactory.registerSingleton("test", advised);
+		this.beanFactory.initializeBean(advised, "test");
+
+		mBeanExporter.afterSingletonsInstantiated();
+		MessageChannel exported = this.beanFactory.getBean("test", MessageChannel.class);
 		exported.send(MessageBuilder.withPayload("test").build());
 	}
 
@@ -91,6 +109,7 @@ public class MessageMetricsAdviceTests {
 		public void handleMessage(Message<?> message) throws MessagingException {
 			invoked = true;
 		}
+		
 	}
 
 	private static class DummyInterceptor implements MethodInterceptor {
@@ -107,5 +126,7 @@ public class MessageMetricsAdviceTests {
 		public String toString() {
 			return super.toString() + "{" + "invoked=" + invoked + '}';
 		}
+		
 	}
+	
 }