[bs-55] Add strategy for setting system exit code

* Added ExitCodeGenerator and SpringApplication.exit
convenience method
* User can add bean of type ExitCodeGenerator or supply
one in the call to exit()

[Fixes #48475971]

spring-bootstrap/src/main/java/org/springframework/bootstrap/ExitCodeGenerator.java

@@ -0,0 +1,26 @@
+/*
+ * Copyright 2012-2013 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.bootstrap;
+
+/**
+ * @author Dave Syer
+ * 
+ */
+public interface ExitCodeGenerator {
+
+	int getExitCode();
+
+}

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

@@ -563,4 +563,49 @@ public class SpringApplication {
 		return new SpringApplication(sources).run(args);
 	}
 
+	/**
+	 * Static helper that can be used to exit a {@link SpringApplication} and obtain a
+	 * code indicating success (0) or otherwise. Does not throw exceptions but should
+	 * print stack traces of any encountered.
+	 * @param context the context to close if possible
+	 * @return the outcome (0 if successful)
+	 */
+	public static int exit(ApplicationContext context,
+			ExitCodeGenerator... exitCodeGenerators) {
+
+		int code = 0;
+
+		List<ExitCodeGenerator> exiters = new ArrayList<ExitCodeGenerator>(
+				Arrays.asList(exitCodeGenerators));
+
+		try {
+
+			exiters.addAll(context.getBeansOfType(ExitCodeGenerator.class).values());
+
+			for (ExitCodeGenerator exiter : exiters) {
+				try {
+					int value = exiter.getExitCode();
+					if (value > code || value < 0 && value < code) {
+						code = value;
+					}
+				} catch (Exception e) {
+					code = code == 0 ? 1 : code;
+					e.printStackTrace();
+				}
+			}
+
+			if (context instanceof ConfigurableApplicationContext) {
+				ConfigurableApplicationContext closable = (ConfigurableApplicationContext) context;
+				closable.close();
+			}
+
+		} catch (Exception e) {
+			code = code == 0 ? 1 : code;
+			e.printStackTrace();
+		}
+
+		return code;
+
+	}
+
 }

spring-bootstrap/src/main/java/org/springframework/bootstrap/autoconfigure/batch/BatchAutoConfiguration.java

@@ -18,6 +18,7 @@ package org.springframework.bootstrap.autoconfigure.batch;
 
 import org.springframework.batch.core.launch.JobLauncher;
 import org.springframework.bootstrap.CommandLineRunner;
+import org.springframework.bootstrap.ExitCodeGenerator;
 import org.springframework.bootstrap.context.annotation.ConditionalOnClass;
 import org.springframework.bootstrap.context.annotation.ConditionalOnMissingBean;
 import org.springframework.bootstrap.context.annotation.EnableAutoConfiguration;
@@ -45,4 +46,10 @@ public class BatchAutoConfiguration {
 		return new JobLauncherCommandLineRunner();
 	}
 
+	@Bean
+	@ConditionalOnMissingBean({ ExitCodeGenerator.class })
+	public ExitCodeGenerator jobExecutionExitCodeGenerator() {
+		return new JobExecutionExitCodeGenerator();
+	}
+
 }

spring-bootstrap/src/main/java/org/springframework/bootstrap/autoconfigure/batch/JobExecutionEvent.java

@@ -0,0 +1,44 @@
+/*
+ * Copyright 2012-2013 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.bootstrap.autoconfigure.batch;
+
+import org.springframework.batch.core.JobExecution;
+import org.springframework.context.ApplicationEvent;
+
+/**
+ * @author Dave Syer
+ * 
+ */
+public class JobExecutionEvent extends ApplicationEvent {
+
+	private JobExecution execution;
+
+	/**
+	 * @param execution
+	 */
+	public JobExecutionEvent(JobExecution execution) {
+		super(execution);
+		this.execution = execution;
+	}
+
+	/**
+	 * @return the job execution
+	 */
+	public JobExecution getJobExecution() {
+		return this.execution;
+	}
+
+}

spring-bootstrap/src/main/java/org/springframework/bootstrap/autoconfigure/batch/JobExecutionExitCodeGenerator.java

@@ -0,0 +1,49 @@
+/*
+ * Copyright 2012-2013 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.bootstrap.autoconfigure.batch;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import org.springframework.batch.core.JobExecution;
+import org.springframework.bootstrap.ExitCodeGenerator;
+import org.springframework.context.ApplicationListener;
+
+/**
+ * @author Dave Syer
+ * 
+ */
+public class JobExecutionExitCodeGenerator implements
+		ApplicationListener<JobExecutionEvent>, ExitCodeGenerator {
+
+	private List<JobExecution> executions = new ArrayList<JobExecution>();
+
+	@Override
+	public void onApplicationEvent(JobExecutionEvent event) {
+		this.executions.add(event.getJobExecution());
+	}
+
+	@Override
+	public int getExitCode() {
+		for (JobExecution execution : this.executions) {
+			if (execution.getStatus().isUnsuccessful()) {
+				return 2;
+			}
+		}
+		return 0;
+	}
+
+}

spring-bootstrap/src/main/java/org/springframework/bootstrap/autoconfigure/batch/JobLauncherCommandLineRunner.java

@@ -21,18 +21,22 @@ import java.util.Properties;
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 import org.springframework.batch.core.Job;
+import org.springframework.batch.core.JobExecution;
 import org.springframework.batch.core.JobExecutionException;
 import org.springframework.batch.core.converter.DefaultJobParametersConverter;
 import org.springframework.batch.core.converter.JobParametersConverter;
 import org.springframework.batch.core.launch.JobLauncher;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.bootstrap.CommandLineRunner;
+import org.springframework.context.ApplicationEventPublisher;
+import org.springframework.context.ApplicationEventPublisherAware;
 import org.springframework.stereotype.Component;
 import org.springframework.util.StringUtils;
 
 @Component
 // FIXME: what to do with more than one Job?
-public class JobLauncherCommandLineRunner implements CommandLineRunner {
+public class JobLauncherCommandLineRunner implements CommandLineRunner,
+		ApplicationEventPublisherAware {
 
 	private static Log logger = LogFactory.getLog(JobLauncherCommandLineRunner.class);
 
@@ -45,18 +49,24 @@ public class JobLauncherCommandLineRunner implements CommandLineRunner {
 	@Autowired
 	private Job job;
 
-	public void run(String... args) {
-		logger.info("Running default command line with: " + Arrays.asList(args));
-		launchJobFromProperties(StringUtils.splitArrayElementsIntoProperties(args,
-				"="));
+	private ApplicationEventPublisher publisher;
+
+	@Override
+	public void setApplicationEventPublisher(ApplicationEventPublisher publisher) {
+		this.publisher = publisher;
 	}
 
-	protected void launchJobFromProperties(Properties properties) {
-		try {
-			this.jobLauncher.run(this.job,
-					this.converter.getJobParameters(properties));
-		} catch (JobExecutionException e) {
-			throw new IllegalStateException("Could not run job", e);
+	public void run(String... args) throws JobExecutionException {
+		logger.info("Running default command line with: " + Arrays.asList(args));
+		launchJobFromProperties(StringUtils.splitArrayElementsIntoProperties(args, "="));
+	}
+
+	protected void launchJobFromProperties(Properties properties)
+			throws JobExecutionException {
+		JobExecution execution = this.jobLauncher.run(this.job,
+				this.converter.getJobParameters(properties));
+		if (this.publisher != null) {
+			this.publisher.publishEvent(new JobExecutionEvent(execution));
 		}
 	}
 }

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

@@ -51,6 +51,7 @@ import org.springframework.web.context.support.StaticWebApplicationContext;
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.instanceOf;
 import static org.hamcrest.Matchers.sameInstance;
+import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertNotNull;
 import static org.junit.Assert.assertThat;
 import static org.junit.Assert.assertTrue;
@@ -279,6 +280,29 @@ public class SpringApplicationTests {
 		assertNotNull(this.context);
 	}
 
+	@Test
+	public void exit() throws Exception {
+		SpringApplication application = new SpringApplication(ExampleConfig.class);
+		application.setWebEnvironment(false);
+		ApplicationContext context = application.run();
+		assertNotNull(context);
+		assertEquals(0, SpringApplication.exit(context));
+	}
+
+	@Test
+	public void exitWithExplicitCOde() throws Exception {
+		SpringApplication application = new SpringApplication(ExampleConfig.class);
+		application.setWebEnvironment(false);
+		ApplicationContext context = application.run();
+		assertNotNull(context);
+		assertEquals(2, SpringApplication.exit(context, new ExitCodeGenerator() {
+			@Override
+			public int getExitCode() {
+				return 2;
+			}
+		}));
+	}
+
 	@Test
 	public void defaultCommandLineArgs() throws Exception {
 		SpringApplication application = new SpringApplication(ExampleConfig.class);