Merge pull request #30457 from dugenkui03

* gh-30457:
  Polish "Order ExitCodeGenerators and return first non-zero exit code"
  Order ExitCodeGenerators and return first non-zero exit code

Closes gh-30457

Author: wilkinsona

spring-boot-project/spring-boot-docs/src/docs/asciidoc/features/spring-application.adoc

@@ -354,6 +354,9 @@ include::code:MyApplication[]
 Also, the `ExitCodeGenerator` interface may be implemented by exceptions.
 When such an exception is encountered, Spring Boot returns the exit code provided by the implemented `getExitCode()` method.
 
+If there is more than `ExitCodeGenerator`, the first non-zero exit code that is generated is used.
+To control the order in which the generators are called, additionally implement the `org.springframework.core.Ordered` interface or use the `org.springframework.core.annotation.Order` annotation.
+
 
 
 [[features.spring-application.admin]]

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/ExitCodeGenerators.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2019 the original author or authors.
+ * Copyright 2012-2022 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.
@@ -21,14 +21,19 @@
 import java.util.Iterator;
 import java.util.List;
 
+import org.springframework.core.Ordered;
+import org.springframework.core.annotation.AnnotationAwareOrderComparator;
+import org.springframework.core.annotation.Order;
 import org.springframework.util.Assert;
 
 /**
- * Maintains a collection of {@link ExitCodeGenerator} instances and allows the final exit
- * code to be calculated.
+ * Maintains an ordered collection of {@link ExitCodeGenerator} instances and allows the
+ * final exit code to be calculated. Generators are ordered by {@link Order @Order} and
+ * {@link Ordered}.
  *
  * @author Dave Syer
  * @author Phillip Webb
+ * @author GenKui Du
  * @see #getExitCode()
  * @see ExitCodeGenerator
  */
@@ -71,6 +76,7 @@ void addAll(Iterable<? extends ExitCodeGenerator> generators) {
 	void add(ExitCodeGenerator generator) {
 		Assert.notNull(generator, "Generator must not be null");
 		this.generators.add(generator);
+		AnnotationAwareOrderComparator.sort(this.generators);
 	}
 
 	@Override
@@ -79,20 +85,22 @@ public Iterator<ExitCodeGenerator> iterator() {
 	}
 
 	/**
-	 * Get the final exit code that should be returned based on all contained generators.
+	 * Get the final exit code that should be returned. The final exit code is the first
+	 * non-zero exit code that is {@link ExitCodeGenerator#getExitCode generated}.
 	 * @return the final exit code.
 	 */
 	int getExitCode() {
 		int exitCode = 0;
 		for (ExitCodeGenerator generator : this.generators) {
 			try {
 				int value = generator.getExitCode();
-				if (value > 0 && value > exitCode || value < 0 && value < exitCode) {
+				if (value != 0) {
 					exitCode = value;
+					break;
 				}
 			}
 			catch (Exception ex) {
-				exitCode = (exitCode != 0) ? exitCode : 1;
+				exitCode = 1;
 				ex.printStackTrace();
 			}
 		}

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

@@ -61,7 +61,9 @@
 import org.springframework.context.support.AbstractApplicationContext;
 import org.springframework.context.support.GenericApplicationContext;
 import org.springframework.core.GenericTypeResolver;
+import org.springframework.core.Ordered;
 import org.springframework.core.annotation.AnnotationAwareOrderComparator;
+import org.springframework.core.annotation.Order;
 import org.springframework.core.env.CommandLinePropertySource;
 import org.springframework.core.env.CompositePropertySource;
 import org.springframework.core.env.ConfigurableEnvironment;
@@ -1320,9 +1322,10 @@ public static void main(String[] args) throws Exception {
 	 * 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. Applies the specified
-	 * {@link ExitCodeGenerator} in addition to any Spring beans that implement
-	 * {@link ExitCodeGenerator}. In the case of multiple exit codes the highest value
-	 * will be used (or if all values are negative, the lowest value will be used)
+	 * {@link ExitCodeGenerator ExitCodeGenerators} in addition to any Spring beans that
+	 * implement {@link ExitCodeGenerator}. When multiple generators are available, the
+	 * first non-zero exit code is used. Generators ordered based on their {@link Ordered}
+	 * implementation and {@link Order @Order} annotation.
 	 * @param context the context to close if possible
 	 * @param exitCodeGenerators exit code generators
 	 * @return the outcome (0 if successful)

spring-boot-project/spring-boot/src/test/java/org/springframework/boot/ExitCodeGeneratorsTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2019 the original author or authors.
+ * Copyright 2012-2022 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.
@@ -21,10 +21,13 @@
 
 import org.junit.jupiter.api.Test;
 
+import org.springframework.core.Ordered;
+
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.Assertions.assertThatIllegalArgumentException;
 import static org.mockito.BDDMockito.given;
 import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.withSettings;
 
 /**
  * Tests for {@link ExitCodeGenerators}.
@@ -62,18 +65,9 @@ void getExitCodeWhenGeneratorThrowsShouldReturnOne() {
 	}
 
 	@Test
-	void getExitCodeWhenAllNegativeShouldReturnLowestValue() {
-		ExitCodeGenerators generators = new ExitCodeGenerators();
-		generators.add(mockGenerator(-1));
-		generators.add(mockGenerator(-3));
-		generators.add(mockGenerator(-2));
-		assertThat(generators.getExitCode()).isEqualTo(-3);
-	}
-
-	@Test
-	void getExitCodeWhenAllPositiveShouldReturnHighestValue() {
+	void getExitCodeWithUnorderedGeneratorsReturnsFirstNonZeroExitCode() {
 		ExitCodeGenerators generators = new ExitCodeGenerators();
-		generators.add(mockGenerator(1));
+		generators.add(mockGenerator(0));
 		generators.add(mockGenerator(3));
 		generators.add(mockGenerator(2));
 		assertThat(generators.getExitCode()).isEqualTo(3);
@@ -89,12 +83,29 @@ void getExitCodeWhenUsingExitCodeExceptionMapperShouldCallMapper() {
 		assertThat(generators.getExitCode()).isEqualTo(2);
 	}
 
+	@Test
+	void getExitCodeWithOrderedGeneratorsReturnsFirstNonZeroExitCode() {
+		ExitCodeGenerators generators = new ExitCodeGenerators();
+		generators.add(orderedMockGenerator(0, 1));
+		generators.add(orderedMockGenerator(1, 3));
+		generators.add(orderedMockGenerator(2, 2));
+		generators.add(mockGenerator(3));
+		assertThat(generators.getExitCode()).isEqualTo(2);
+	}
+
 	private ExitCodeGenerator mockGenerator(int exitCode) {
 		ExitCodeGenerator generator = mock(ExitCodeGenerator.class);
 		given(generator.getExitCode()).willReturn(exitCode);
 		return generator;
 	}
 
+	private ExitCodeGenerator orderedMockGenerator(int exitCode, int order) {
+		ExitCodeGenerator generator = mock(ExitCodeGenerator.class, withSettings().extraInterfaces(Ordered.class));
+		given(generator.getExitCode()).willReturn(exitCode);
+		given(((Ordered) generator).getOrder()).willReturn(order);
+		return generator;
+	}
+
 	private ExitCodeExceptionMapper mockMapper(Class<?> exceptionType, int exitCode) {
 		return (exception) -> {
 			if (exceptionType.isInstance(exception)) {