Auto-configure @EnableConfigurationProperties

Add an auto-configuration that avoid a Spring Boot user to add
`@EnableConfigurationProperties` to its configuration to benefit from
that feature.

As our own auto-configurations are tested independently, such annotation
is still present to avoid a useless reference to this new
auto-configuration.

Closes gh-2457

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/context/ConfigurationPropertiesAutoConfiguration.java

@@ -0,0 +1,37 @@
+/*
+ * 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.autoconfigure.context;
+
+import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
+import org.springframework.boot.context.properties.ConfigurationProperties;
+import org.springframework.boot.context.properties.EnableConfigurationProperties;
+import org.springframework.context.annotation.Configuration;
+
+/**
+ * {@link EnableAutoConfiguration Auto-configuration} for {@link ConfigurationProperties}
+ * annotated beans. Automatically any bean annotated with {@code @ConfigurationProperties}.
+ *
+ * @author Stephane Nicoll
+ * @since 1.3.0
+ * @see EnableConfigurationProperties
+ * @see ConfigurationProperties
+ */
+@Configuration
+@EnableConfigurationProperties
+public class ConfigurationPropertiesAutoConfiguration {
+
+}

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/context/package-info.java

@@ -0,0 +1,20 @@
+/*
+ * 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.
+ */
+
+/**
+ * Auto-configuration for the Spring context.
+ */
+package org.springframework.boot.autoconfigure.context;

spring-boot-autoconfigure/src/main/resources/META-INF/spring.factories

@@ -12,6 +12,7 @@ org.springframework.boot.autoconfigure.PropertyPlaceholderAutoConfiguration,\
 org.springframework.boot.autoconfigure.batch.BatchAutoConfiguration,\
 org.springframework.boot.autoconfigure.cache.CacheAutoConfiguration,\
 org.springframework.boot.autoconfigure.cloud.CloudAutoConfiguration,\
+org.springframework.boot.autoconfigure.context.ConfigurationPropertiesAutoConfiguration,\
 org.springframework.boot.autoconfigure.dao.PersistenceExceptionTranslationAutoConfiguration,\
 org.springframework.boot.autoconfigure.data.elasticsearch.ElasticsearchRepositoriesAutoConfiguration,\
 org.springframework.boot.autoconfigure.data.jpa.JpaRepositoriesAutoConfiguration,\

spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/context/ConfigurationPropertiesAutoConfigurationTests.java

@@ -0,0 +1,83 @@
+/*
+ * 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.autoconfigure.context;
+
+import org.junit.After;
+import org.junit.Test;
+
+import org.springframework.boot.context.properties.ConfigurationProperties;
+import org.springframework.boot.test.EnvironmentTestUtils;
+import org.springframework.context.annotation.AnnotationConfigApplicationContext;
+import org.springframework.stereotype.Component;
+
+import static org.hamcrest.core.Is.is;
+import static org.junit.Assert.assertThat;
+
+/**
+ * Tests for {@link ConfigurationPropertiesAutoConfiguration}.
+ *
+ * @author Stephane Nicoll
+ */
+public class ConfigurationPropertiesAutoConfigurationTests {
+
+	private AnnotationConfigApplicationContext context;
+
+	@After
+	public void tearDown() {
+		if (this.context != null) {
+			this.context.close();
+		}
+	}
+
+	@Test
+	public void processAnnotatedBean() {
+		load(new Class[] {SampleBean.class, ConfigurationPropertiesAutoConfiguration.class},
+				"foo.name:test");
+		assertThat(this.context.getBean(SampleBean.class).getName(), is("test"));
+	}
+
+	@Test
+	public void processAnnotatedBeanNoAutoConfig() {
+		load(new Class[] {SampleBean.class}, "foo.name:test");
+		assertThat(this.context.getBean(SampleBean.class).getName(), is("default"));
+	}
+
+	private void load(Class<?>[] configs,
+			String... environment) {
+		this.context = new AnnotationConfigApplicationContext();
+		this.context.register(configs);
+		EnvironmentTestUtils.addEnvironment(this.context, environment);
+		this.context.refresh();
+	}
+
+
+	@Component
+	@ConfigurationProperties("foo")
+	private static class SampleBean {
+
+		private String name = "default";
+
+		public String getName() {
+			return this.name;
+		}
+
+		public void setName(String name) {
+			this.name = name;
+		}
+	}
+
+}

spring-boot-docs/src/main/asciidoc/spring-boot-features.adoc

@@ -630,9 +630,9 @@ Nested POJO properties can also be created (so a setter is not mandatory) if the
 default constructor, or a constructor accepting a single value that can be coerced from
 String. Some people use Project Lombok to add getters and setters automatically.
 
-When the `@EnableConfigurationProperties` annotation is applied to your `@Configuration`,
-any beans annotated with `@ConfigurationProperties` will be automatically configured from
-the `Environment` properties. This style of configuration works particularly well with the
+The `@EnableConfigurationProperties` annotation is automatically applied to your project
+so that any beans annotated with `@ConfigurationProperties` will be configured from the
+`Environment` properties. This style of configuration works particularly well with the
 `SpringApplication` external YAML configuration:
 
 [source,yaml,indent=0]

spring-boot-samples/spring-boot-sample-property-validation/src/main/java/sample/propertyvalidation/SamplePropertyValidationApplication.java

@@ -20,14 +20,12 @@ import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.boot.CommandLineRunner;
 import org.springframework.boot.autoconfigure.SpringBootApplication;
 import org.springframework.boot.builder.SpringApplicationBuilder;
-import org.springframework.boot.context.properties.EnableConfigurationProperties;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Profile;
 import org.springframework.stereotype.Service;
 import org.springframework.validation.Validator;
 
 @SpringBootApplication
-@EnableConfigurationProperties
 public class SamplePropertyValidationApplication {
 
 	@Bean