Publish ExitCodeEvent when possible

Update SpringApplication to publish an ExitCodeEvent when a valid exit
code is known.

Fixes gh-4804

spring-boot/src/main/java/org/springframework/boot/ExitCodeEvent.java

+/*
+ * Copyright 2012-2015 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
+ *
+ *      http://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.boot;
+
+import org.springframework.context.ApplicationEvent;
+
+/**
+ * Event fired when an application exit code has been determined from an
+ * {@link ExitCodeGenerator}.
+ *
+ * @author Phillip Webb
+ * @since 1.3.2
+ */
+public class ExitCodeEvent extends ApplicationEvent {
+
+	private final int exitCode;
+
+	/**
+	 * Create a new {@link ExitCodeEvent} instance.
+	 * @param source the source of the event
+	 * @param exitCode the exit code
+	 */
+	public ExitCodeEvent(Object source, int exitCode) {
+		super(source);
+		this.exitCode = exitCode;
+	}
+
+	/**
+	 * Return the exit code that will be used to exit the JVM.
+	 * @return the the exit code
+	 */
+	public int getExitCode() {
+		return this.exitCode;
+	}
+
+}

spring-boot/src/main/java/org/springframework/boot/SpringApplication.java

@@ -302,7 +302,11 @@ public class SpringApplication {
 		SpringApplicationRunListeners listeners = getRunListeners(args);
 		listeners.started();
 		try {
-			context = doRun(listeners, args);
+			ApplicationArguments applicationArguments = new DefaultApplicationArguments(
+					args);
+			context = createAndRefreshContext(listeners, applicationArguments);
+			afterRefresh(context, applicationArguments);
+			listeners.finished(context, null);
 			stopWatch.stop();
 			if (this.logStartupInfo) {
 				new StartupInfoLogger(this.mainApplicationClass)
@@ -316,12 +320,13 @@ public class SpringApplication {
 		}
 	}
 
-	private ConfigurableApplicationContext doRun(SpringApplicationRunListeners listeners,
-			String... args) {
+	private ConfigurableApplicationContext createAndRefreshContext(
+			SpringApplicationRunListeners listeners,
+			ApplicationArguments applicationArguments) {
 		ConfigurableApplicationContext context;
 		// Create and configure the environment
 		ConfigurableEnvironment environment = getOrCreateEnvironment();
-		configureEnvironment(environment, args);
+		configureEnvironment(environment, applicationArguments.getSourceArgs());
 		listeners.environmentPrepared(environment);
 		if (isWebEnvironment(environment) && !this.webEnvironment) {
 			environment = convertToStandardEnvironment(environment);
@@ -343,7 +348,6 @@ public class SpringApplication {
 		}
 
 		// Add boot specific singleton beans
-		ApplicationArguments applicationArguments = new DefaultApplicationArguments(args);
 		context.getBeanFactory().registerSingleton("springApplicationArguments",
 				applicationArguments);
 
@@ -363,8 +367,6 @@ public class SpringApplication {
 				// Not allowed in some environments.
 			}
 		}
-		afterRefresh(context, applicationArguments);
-		listeners.finished(context, null);
 		return context;
 	}
 
@@ -858,6 +860,9 @@ public class SpringApplication {
 			Throwable exception) {
 		int exitCode = getExitCodeFromException(exception);
 		if (exitCode != 0) {
+			if (context != null) {
+				context.publishEvent(new ExitCodeEvent(context, exitCode));
+			}
 			SpringBootExceptionHandler handler = getSpringBootExceptionHandler();
 			if (handler != null) {
 				handler.registerExitCode(exitCode);
@@ -1186,6 +1191,7 @@ public class SpringApplication {
 	 */
 	public static int exit(ApplicationContext context,
 			ExitCodeGenerator... exitCodeGenerators) {
+		Assert.notNull(context, "Context must not be null");
 		int exitCode = 0;
 		try {
 			try {
@@ -1195,6 +1201,9 @@ public class SpringApplication {
 				generators.addAll(exitCodeGenerators);
 				generators.addAll(beans);
 				exitCode = generators.getExitCode();
+				if (exitCode != 0) {
+					context.publishEvent(new ExitCodeEvent(context, exitCode));
+				}
 			}
 			finally {
 				close(context);

spring-boot/src/test/java/org/springframework/boot/SpringApplicationTests.java

@@ -549,6 +549,8 @@ public class SpringApplicationTests {
 	@Test
 	public void exitWithExplicitCode() throws Exception {
 		SpringApplication application = new SpringApplication(ExampleConfig.class);
+		ExitCodeListener listener = new ExitCodeListener();
+		application.addListeners(listener);
 		application.setWebEnvironment(false);
 		this.context = application.run();
 		assertNotNull(this.context);
@@ -560,6 +562,7 @@ public class SpringApplicationTests {
 			}
 
 		}));
+		assertThat(listener.getExitCode(), equalTo(2));
 	}
 
 	@Test
@@ -574,6 +577,8 @@ public class SpringApplicationTests {
 			}
 
 		};
+		ExitCodeListener listener = new ExitCodeListener();
+		application.addListeners(listener);
 		application.setWebEnvironment(false);
 		try {
 			application.run();
@@ -582,6 +587,7 @@ public class SpringApplicationTests {
 		catch (IllegalStateException ex) {
 		}
 		verify(handler).registerExitCode(11);
+		assertThat(listener.getExitCode(), equalTo(11));
 	}
 
 	@Test
@@ -982,4 +988,18 @@ public class SpringApplicationTests {
 
 	}
 
+	private static class ExitCodeListener implements ApplicationListener<ExitCodeEvent> {
+
+		private int exitCode;
+
+		@Override
+		public void onApplicationEvent(ExitCodeEvent event) {
+			this.exitCode = event.getExitCode();
+		}
+
+		public int getExitCode() {
+			return this.exitCode;
+		}
+
+	}
 }