Use `@AliasFor` when applicable

This commit adds `@AliasFor` meta-data to annotations that declare an
alias attribute.

`@ConditionalOnProperty` and `@AutoconfigureRestDocs` were not migrated
due to the use of `AnnotationMetadata#getAnnotationAttributes`.

Closes gh-5187

spring-boot-actuator/src/main/java/org/springframework/boot/actuate/endpoint/ConfigurationPropertiesReportEndpoint.java

@@ -220,8 +220,7 @@ public class ConfigurationPropertiesReportEndpoint
 				annotation = override;
 			}
 		}
-		return (StringUtils.hasLength(annotation.value()) ? annotation.value()
+		return annotation.prefix();
-				: annotation.prefix());
 	}
 
 	/**

spring-boot-actuator/src/main/java/org/springframework/boot/actuate/endpoint/mvc/MvcEndpoints.java

@@ -30,7 +30,6 @@ import org.springframework.context.ApplicationContextAware;
 import org.springframework.core.annotation.AnnotationUtils;
 import org.springframework.core.env.Environment;
 import org.springframework.stereotype.Component;
-import org.springframework.util.StringUtils;
 
 /**
  * A registry for all {@link MvcEndpoint} beans, and a factory for a set of generic ones
@@ -102,9 +101,7 @@ public class MvcEndpoints implements ApplicationContextAware, InitializingBean {
 		ConfigurationProperties configurationProperties = AnnotationUtils
 				.findAnnotation(endpoint.getClass(), ConfigurationProperties.class);
 		if (configurationProperties != null) {
-			String prefix = StringUtils.hasText(configurationProperties.prefix())
+			return environment.getProperty(configurationProperties.prefix() + ".path");
-					? configurationProperties.prefix() : configurationProperties.value();
-			return environment.getProperty(prefix + ".path");
 		}
 		return null;
 	}

spring-boot/src/main/java/org/springframework/boot/context/properties/ConfigurationProperties.java

@@ -22,6 +22,8 @@ import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;
 import java.lang.annotation.Target;
 
+import org.springframework.core.annotation.AliasFor;
+
 /**
  * Annotation for externalized configuration. Add this to a class definition or a
  * {@code @Bean} method in a {@code @Configuration} class if you want to bind and validate
@@ -44,6 +46,7 @@ public @interface ConfigurationProperties {
 	 * for {@link #prefix()}.
 	 * @return the name prefix of the properties to bind
 	 */
+	@AliasFor("prefix")
 	String value() default "";
 
 	/**
@@ -51,6 +54,7 @@ public @interface ConfigurationProperties {
 	 * for {@link #value()}.
 	 * @return the name prefix of the properties to bind
 	 */
+	@AliasFor("value")
 	String prefix() default "";
 
 	/**

spring-boot/src/main/java/org/springframework/boot/context/properties/ConfigurationPropertiesBindingPostProcessor.java

@@ -325,10 +325,8 @@ public class ConfigurationPropertiesBindingPostProcessor
 			factory.setIgnoreUnknownFields(annotation.ignoreUnknownFields());
 			factory.setExceptionIfInvalid(annotation.exceptionIfInvalid());
 			factory.setIgnoreNestedProperties(annotation.ignoreNestedProperties());
-			String targetName = (StringUtils.hasLength(annotation.value())
+			if (StringUtils.hasLength(annotation.prefix())) {
-					? annotation.value() : annotation.prefix());
+				factory.setTargetName(annotation.prefix());
-			if (StringUtils.hasLength(targetName)) {
-				factory.setTargetName(targetName);
 			}
 		}
 		try {
@@ -346,8 +344,7 @@ public class ConfigurationPropertiesBindingPostProcessor
 			return "";
 		}
 		StringBuilder details = new StringBuilder();
-		details.append("prefix=").append((StringUtils.hasLength(annotation.value())
+		details.append("prefix=").append(annotation.prefix());
-				? annotation.value() : annotation.prefix()));
 		details.append(", ignoreInvalidFields=").append(annotation.ignoreInvalidFields());
 		details.append(", ignoreUnknownFields=").append(annotation.ignoreUnknownFields());
 		details.append(", ignoreNestedProperties=")

spring-boot/src/main/java/org/springframework/boot/context/properties/EnableConfigurationPropertiesImportSelector.java

@@ -88,8 +88,7 @@ class EnableConfigurationPropertiesImportSelector implements ImportSelector {
 			ConfigurationProperties annotation = AnnotationUtils.findAnnotation(type,
 					ConfigurationProperties.class);
 			if (annotation != null) {
-				return (StringUtils.hasLength(annotation.value()) ? annotation.value()
+				return annotation.prefix();
-						: annotation.prefix());
 			}
 			return "";
 		}

spring-boot/src/main/java/org/springframework/boot/context/scan/AbstractEntityScanRegistrar.java

@@ -29,9 +29,7 @@ import org.springframework.beans.factory.support.GenericBeanDefinition;
 import org.springframework.context.annotation.ImportBeanDefinitionRegistrar;
 import org.springframework.core.annotation.AnnotationAttributes;
 import org.springframework.core.type.AnnotationMetadata;
-import org.springframework.util.Assert;
 import org.springframework.util.ClassUtils;
-import org.springframework.util.ObjectUtils;
 
 /**
  * A base {@link ImportBeanDefinitionRegistrar} used to collect the packages to scan for a
@@ -88,17 +86,9 @@ public abstract class AbstractEntityScanRegistrar
 	protected Set<String> getPackagesToScan(AnnotationMetadata metadata) {
 		AnnotationAttributes attributes = AnnotationAttributes
 				.fromMap(metadata.getAnnotationAttributes(this.annotationType.getName()));
-		String[] value = attributes.getStringArray("value");
 		String[] basePackages = attributes.getStringArray("basePackages");
 		Class<?>[] basePackageClasses = attributes.getClassArray("basePackageClasses");
-		if (!ObjectUtils.isEmpty(value)) {
-			Assert.state(ObjectUtils.isEmpty(basePackages),
-					String.format(
-							"@%s basePackages and value attributes are mutually exclusive",
-							this.annotationType.getSimpleName()));
-		}
 		Set<String> packagesToScan = new LinkedHashSet<String>();
-		packagesToScan.addAll(Arrays.asList(value));
 		packagesToScan.addAll(Arrays.asList(basePackages));
 		for (Class<?> basePackageClass : basePackageClasses) {
 			packagesToScan.add(ClassUtils.getPackageName(basePackageClass));

spring-boot/src/main/java/org/springframework/boot/neo4j/NodeEntityScan.java

@@ -26,6 +26,7 @@ import org.neo4j.ogm.annotation.NodeEntity;
 import org.neo4j.ogm.session.SessionFactory;
 
 import org.springframework.context.annotation.Import;
+import org.springframework.core.annotation.AliasFor;
 
 /**
  * Configures the {@link SessionFactory} to scan for Neo4J {@link NodeEntity} classes in
@@ -58,6 +59,7 @@ public @interface NodeEntityScan {
 	 * {@code @NodeEntityScan(basePackages="org.my.pkg")}.
 	 * @return the base packages to scan
 	 */
+	@AliasFor("basePackages")
 	String[] value() default {};
 
 	/**
@@ -68,6 +70,7 @@ public @interface NodeEntityScan {
 	 * package names.
 	 * @return the base packages to scan
 	 */
+	@AliasFor("value")
 	String[] basePackages() default {};
 
 	/**

spring-boot/src/main/java/org/springframework/boot/orm/jpa/EntityScan.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2015 the original author or authors.
+ * Copyright 2012-2016 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.
@@ -23,6 +23,7 @@ import java.lang.annotation.RetentionPolicy;
 import java.lang.annotation.Target;
 
 import org.springframework.context.annotation.Import;
+import org.springframework.core.annotation.AliasFor;
 import org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean;
 
 /**
@@ -55,6 +56,7 @@ public @interface EntityScan {
 	 * {@code @EntityScan(basePackages="org.my.pkg")}.
 	 * @return the base packages to scan
 	 */
+	@AliasFor("basePackages")
 	String[] value() default {};
 
 	/**
@@ -65,6 +67,7 @@ public @interface EntityScan {
 	 * package names.
 	 * @return the base packages to scan
 	 */
+	@AliasFor("value")
 	String[] basePackages() default {};
 
 	/**

spring-boot/src/main/java/org/springframework/boot/web/servlet/ServletComponentScan.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2015 the original author or authors.
+ * Copyright 2012-2016 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.
@@ -27,6 +27,7 @@ import javax.servlet.annotation.WebListener;
 import javax.servlet.annotation.WebServlet;
 
 import org.springframework.context.annotation.Import;
+import org.springframework.core.annotation.AliasFor;
 
 /**
  * Enables scanning for Servlet components ({@link WebFilter filters}, {@link WebServlet
@@ -55,6 +56,7 @@ public @interface ServletComponentScan {
 	 * {@code @ServletComponentScan(basePackages="org.my.pkg")}.
 	 * @return the base packages to scan
 	 */
+	@AliasFor("basePackages")
 	String[] value() default {};
 
 	/**
@@ -65,6 +67,7 @@ public @interface ServletComponentScan {
 	 * package names.
 	 * @return the base packages to scan
 	 */
+	@AliasFor("value")
 	String[] basePackages() default {};
 
 	/**

spring-boot/src/main/java/org/springframework/boot/web/servlet/ServletComponentScanRegistrar.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2015 the original author or authors.
+ * Copyright 2012-2016 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.
@@ -28,14 +28,13 @@ import org.springframework.beans.factory.support.GenericBeanDefinition;
 import org.springframework.context.annotation.ImportBeanDefinitionRegistrar;
 import org.springframework.core.annotation.AnnotationAttributes;
 import org.springframework.core.type.AnnotationMetadata;
-import org.springframework.util.Assert;
 import org.springframework.util.ClassUtils;
-import org.springframework.util.ObjectUtils;
 
 /**
  * {@link ImportBeanDefinitionRegistrar} used by {@link ServletComponentScan}.
  *
  * @author Andy Wilkinson
+ * @author Stephane Nicoll
  */
 class ServletComponentScanRegistrar implements ImportBeanDefinitionRegistrar {
 
@@ -77,16 +76,9 @@ class ServletComponentScanRegistrar implements ImportBeanDefinitionRegistrar {
 	private Set<String> getPackagesToScan(AnnotationMetadata metadata) {
 		AnnotationAttributes attributes = AnnotationAttributes.fromMap(
 				metadata.getAnnotationAttributes(ServletComponentScan.class.getName()));
-		String[] value = attributes.getStringArray("value");
 		String[] basePackages = attributes.getStringArray("basePackages");
 		Class<?>[] basePackageClasses = attributes.getClassArray("basePackageClasses");
-		if (!ObjectUtils.isEmpty(value)) {
-			Assert.state(ObjectUtils.isEmpty(basePackages),
-					"@ServletComponentScan basePackages and value attributes are"
-							+ " mutually exclusive");
-		}
 		Set<String> packagesToScan = new LinkedHashSet<String>();
-		packagesToScan.addAll(Arrays.asList(value));
 		packagesToScan.addAll(Arrays.asList(basePackages));
 		for (Class<?> basePackageClass : basePackageClasses) {
 			packagesToScan.add(ClassUtils.getPackageName(basePackageClass));

spring-boot/src/test/java/org/springframework/boot/context/scan/TestEntityScan.java

@@ -23,6 +23,7 @@ import java.lang.annotation.RetentionPolicy;
 import java.lang.annotation.Target;
 
 import org.springframework.context.annotation.Import;
+import org.springframework.core.annotation.AliasFor;
 
 /**
  * EntityScan test annotation.
@@ -35,8 +36,10 @@ import org.springframework.context.annotation.Import;
 @Import(TestEntityScanRegistrar.class)
 public @interface TestEntityScan {
 
+	@AliasFor("basePackages")
 	String[] value() default {};
 
+	@AliasFor("value")
 	String[] basePackages() default {};
 
 	Class<?>[] basePackageClasses() default {};

spring-boot/src/test/java/org/springframework/boot/context/scan/TestEntityScanTests.java

@@ -25,6 +25,7 @@ import org.springframework.boot.context.scan.TestEntityScanRegistrar.TestFactory
 import org.springframework.context.annotation.AnnotationConfigApplicationContext;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
+import org.springframework.core.annotation.AnnotationConfigurationException;
 
 import static org.assertj.core.api.Assertions.assertThat;
 
@@ -75,10 +76,11 @@ public class TestEntityScanTests {
 
 	@Test
 	public void valueAndBasePackagesThrows() throws Exception {
-		this.thrown.expect(IllegalStateException.class);
+		this.thrown.expect(AnnotationConfigurationException.class);
-		this.thrown.expectMessage("@TestEntityScan basePackages and value "
+		this.thrown.expectMessage("attribute 'value' and its alias 'basePackages' are declared");
-				+ "attributes are mutually exclusive");
+		this.thrown.expectMessage("com.mycorp.entity");
-		this.context = new AnnotationConfigApplicationContext(ValueAndBasePackages.class);
+		this.thrown.expectMessage("com.mycorp");
+		new AnnotationConfigApplicationContext(ValueAndBasePackages.class);
 	}
 
 	@Test

spring-boot/src/test/java/org/springframework/boot/web/servlet/ServletComponentScanRegistrarTests.java

@@ -23,6 +23,7 @@ import org.junit.rules.ExpectedException;
 
 import org.springframework.context.annotation.AnnotationConfigApplicationContext;
 import org.springframework.context.annotation.Configuration;
+import org.springframework.core.annotation.AnnotationConfigurationException;
 
 import static org.assertj.core.api.Assertions.assertThat;
 
@@ -74,14 +75,9 @@ public class ServletComponentScanRegistrarTests {
 
 	@Test
 	public void packagesConfiguredWithBothValueAndBasePackages() {
-		this.thrown.expect(IllegalStateException.class);
+		this.thrown.expect(AnnotationConfigurationException.class);
-		this.thrown.expectMessage("@ServletComponentScan basePackages and value"
+		this.thrown.expectMessage("attribute 'value' and its alias 'basePackages' are declared");
-				+ " attributes are mutually exclusive");
+		new AnnotationConfigApplicationContext(ValueAndBasePackages.class);
-		this.context = new AnnotationConfigApplicationContext(ValueAndBasePackages.class);
-		ServletComponentRegisteringPostProcessor postProcessor = this.context
-				.getBean(ServletComponentRegisteringPostProcessor.class);
-		assertThat(postProcessor.getPackagesToScan())
-				.contains(getClass().getPackage().getName());
 	}
 
 	@Test