Only use Converters which are @ConfigurationPropertiesBinder qualified

Users sometimes create beans of type Converter and don't expect that to
automatically trigger a cascade of early initialization. This change adds
a qualifier to the Converters that are used by @ConfigurationProperties,
so they can be isolated (and simple).

Fixes gh-2669

Author: Dave Syer

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

@@ -761,7 +761,8 @@ The following properties names can all be used:
 Spring will attempt to coerce the external application properties to the right type when
 it binds to the `@ConfigurationProperties` beans. If you need custom type conversion you
 can provide a `ConversionService` bean (with bean id `conversionService`) or custom
-property editors (via a `CustomEditorConfigurer` bean).
+property editors (via a `CustomEditorConfigurer` bean) or custom `Converters` (with
+bean definitions annotated as `@ConfigurationPropertiesBinding`).
 
 
 

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

@@ -0,0 +1,38 @@
+/*
+ * 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.context.properties;
+
+import java.lang.annotation.Documented;
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+import org.springframework.beans.factory.annotation.Qualifier;
+
+/**
+ * Qualifier for beans that are needed to configure the binding of
+ * {@link ConfigurationProperties} (e.g. Converters).
+ *
+ * @author Dave Syer
+ */
+@Qualifier
+@Target({ ElementType.TYPE, ElementType.METHOD })
+@Retention(RetentionPolicy.RUNTIME)
+@Documented
+public @interface ConfigurationPropertiesBinding {
+}

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

@@ -17,7 +17,9 @@
 package org.springframework.boot.context.properties;
 
 import java.io.IOException;
+import java.util.Collections;
 import java.util.Iterator;
+import java.util.List;
 import java.util.Map;
 
 import org.springframework.beans.BeansException;
@@ -28,6 +30,7 @@
 import org.springframework.beans.factory.InitializingBean;
 import org.springframework.beans.factory.ListableBeanFactory;
 import org.springframework.beans.factory.NoSuchBeanDefinitionException;
+import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.beans.factory.config.BeanPostProcessor;
 import org.springframework.boot.bind.PropertiesConfigurationFactory;
 import org.springframework.boot.env.PropertySourcesLoader;
@@ -69,13 +72,13 @@
  * @author Stephane Nicoll
  */
 public class ConfigurationPropertiesBindingPostProcessor implements BeanPostProcessor,
-		BeanFactoryAware, ResourceLoaderAware, EnvironmentAware, ApplicationContextAware,
-		InitializingBean, DisposableBean, PriorityOrdered {
+BeanFactoryAware, ResourceLoaderAware, EnvironmentAware, ApplicationContextAware,
+InitializingBean, DisposableBean, PriorityOrdered {
 
 	public static final String VALIDATOR_BEAN_NAME = "configurationPropertiesValidator";
 
 	private static final String[] VALIDATOR_CLASSES = { "javax.validation.Validator",
-			"javax.validation.ValidatorFactory" };
+	"javax.validation.ValidatorFactory" };
 
 	private ConfigurationBeanFactoryMetaData beans = new ConfigurationBeanFactoryMetaData();
 
@@ -97,8 +100,21 @@ public class ConfigurationPropertiesBindingPostProcessor implements BeanPostProc
 
 	private ApplicationContext applicationContext;
 
+	private List<Converter<?, ?>> converters = Collections.emptyList();
+
 	private int order = Ordered.HIGHEST_PRECEDENCE + 1;
 
+	/**
+	 * A list of custom converters (in addition to the defaults) to use when
+	 * converting properties for binding.
+	 * @param converters the converters to set
+	 */
+	@Autowired(required = false)
+	@ConfigurationPropertiesBinding
+	public void setConverters(List<Converter<?, ?>> converters) {
+		this.converters = converters;
+	}
+
 	/**
 	 * @param order the order to set
 	 */
@@ -246,8 +262,8 @@ private <T> T getOptionalBean(String name, Class<T> type) {
 	@Override
 	public Object postProcessBeforeInitialization(Object bean, String beanName)
 			throws BeansException {
-		ConfigurationProperties annotation = AnnotationUtils.findAnnotation(
-				bean.getClass(), ConfigurationProperties.class);
+		ConfigurationProperties annotation = AnnotationUtils
+				.findAnnotation(bean.getClass(), ConfigurationProperties.class);
 		if (annotation != null || bean instanceof ConfigurationPropertiesHolder) {
 			postProcessBeforeInitialization(bean, beanName, annotation);
 		}
@@ -267,29 +283,29 @@ public Object postProcessAfterInitialization(Object bean, String beanName)
 
 	private void postProcessBeforeInitialization(Object bean, String beanName,
 			ConfigurationProperties annotation) {
-		Object target = (bean instanceof ConfigurationPropertiesHolder ? ((ConfigurationPropertiesHolder) bean)
-				.getTarget() : bean);
+		Object target = (bean instanceof ConfigurationPropertiesHolder
+				? ((ConfigurationPropertiesHolder) bean).getTarget() : bean);
 		PropertiesConfigurationFactory<Object> factory = new PropertiesConfigurationFactory<Object>(
 				target);
 		if (annotation != null && annotation.locations().length != 0) {
-			factory.setPropertySources(loadPropertySources(annotation.locations(),
-					annotation.merge()));
+			factory.setPropertySources(
+					loadPropertySources(annotation.locations(), annotation.merge()));
 		}
 		else {
 			factory.setPropertySources(this.propertySources);
 		}
 		factory.setValidator(determineValidator(bean));
 		// If no explicit conversion service is provided we add one so that (at least)
 		// comma-separated arrays of convertibles can be bound automatically
-		factory.setConversionService(this.conversionService == null ? getDefaultConversionService()
-				: this.conversionService);
+		factory.setConversionService(this.conversionService == null
+				? getDefaultConversionService() : this.conversionService);
 		if (annotation != null) {
 			factory.setIgnoreInvalidFields(annotation.ignoreInvalidFields());
 			factory.setIgnoreUnknownFields(annotation.ignoreUnknownFields());
 			factory.setExceptionIfInvalid(annotation.exceptionIfInvalid());
 			factory.setIgnoreNestedProperties(annotation.ignoreNestedProperties());
-			String targetName = (StringUtils.hasLength(annotation.value()) ? annotation
-					.value() : annotation.prefix());
+			String targetName = (StringUtils.hasLength(annotation.value())
+					? annotation.value() : annotation.prefix());
 			if (StringUtils.hasLength(targetName)) {
 				factory.setTargetName(targetName);
 			}
@@ -300,7 +316,8 @@ private void postProcessBeforeInitialization(Object bean, String beanName,
 		catch (Exception ex) {
 			String targetClass = ClassUtils.getShortName(target.getClass());
 			throw new BeanCreationException(beanName, "Could not bind properties to "
-					+ targetClass + " (" + getAnnotationDetails(annotation) + ")", ex);
+					+ targetClass + " (" + getAnnotationDetails(annotation) + ")",
+					ex);
 		}
 	}
 
@@ -309,19 +326,18 @@ private String getAnnotationDetails(ConfigurationProperties annotation) {
 			return "";
 		}
 		StringBuilder details = new StringBuilder();
-		details.append("prefix=").append(
-				(StringUtils.hasLength(annotation.value()) ? annotation.value()
-						: annotation.prefix()));
+		details.append("prefix=").append((StringUtils.hasLength(annotation.value())
+				? annotation.value() : annotation.prefix()));
 		details.append(", ignoreInvalidFields=").append(annotation.ignoreInvalidFields());
 		details.append(", ignoreUnknownFields=").append(annotation.ignoreUnknownFields());
-		details.append(", ignoreNestedProperties=").append(
-				annotation.ignoreNestedProperties());
+		details.append(", ignoreNestedProperties=")
+		.append(annotation.ignoreNestedProperties());
 		return details.toString();
 	}
 
 	private Validator determineValidator(Object bean) {
-		boolean globalValidatorSupportBean = (this.validator != null && this.validator
-				.supports(bean.getClass()));
+		boolean globalValidatorSupportBean = (this.validator != null
+				&& this.validator.supports(bean.getClass()));
 		if (ClassUtils.isAssignable(Validator.class, bean.getClass())) {
 			if (!globalValidatorSupportBean) {
 				return (Validator) bean;
@@ -336,8 +352,8 @@ private PropertySources loadPropertySources(String[] locations,
 		try {
 			PropertySourcesLoader loader = new PropertySourcesLoader();
 			for (String location : locations) {
-				Resource resource = this.resourceLoader.getResource(this.environment
-						.resolvePlaceholders(location));
+				Resource resource = this.resourceLoader
+						.getResource(this.environment.resolvePlaceholders(location));
 				String[] profiles = this.environment.getActiveProfiles();
 				for (int i = profiles.length; i-- > 0;) {
 					String profile = profiles[i];
@@ -361,8 +377,9 @@ private PropertySources loadPropertySources(String[] locations,
 	private ConversionService getDefaultConversionService() {
 		if (this.defaultConversionService == null) {
 			DefaultConversionService conversionService = new DefaultConversionService();
-			for (Converter<?, ?> converter : ((ListableBeanFactory) this.beanFactory)
-					.getBeansOfType(Converter.class, false, false).values()) {
+			this.applicationContext.getAutowireCapableBeanFactory()
+			.autowireBean(this);
+			for (Converter<?, ?> converter : this.converters) {
 				conversionService.addConverter(converter);
 			}
 			this.defaultConversionService = conversionService;
@@ -371,8 +388,8 @@ private ConversionService getDefaultConversionService() {
 	}
 
 	/**
-	 * Factory to create JSR 303 LocalValidatorFactoryBean. Inner class to prevent class
-	 * loader issues.
+	 * Factory to create JSR 303 LocalValidatorFactoryBean. Inner class to prevent
+	 * class loader issues.
 	 */
 	private static class Jsr303ValidatorFactory {
 
@@ -386,8 +403,8 @@ public Validator run(ApplicationContext applicationContext) {
 	}
 
 	/**
-	 * {@link Validator} implementation that wraps {@link Validator} instances and chains
-	 * their execution.
+	 * {@link Validator} implementation that wraps {@link Validator} instances and
+	 * chains their execution.
 	 */
 	private static class ChainingValidator implements Validator {
 
@@ -421,7 +438,8 @@ public void validate(Object target, Errors errors) {
 
 	/**
 	 * Convenience class to flatten out a tree of property sources without losing the
-	 * reference to the backing data (which can therefore be updated in the background).
+	 * reference to the backing data (which can therefore be updated in the
+	 * background).
 	 */
 	private static class FlatPropertySources implements PropertySources {
 

spring-boot/src/test/java/org/springframework/boot/bind/ConverterBindingTests.java

@@ -0,0 +1,110 @@
+/*
+ * Copyright 2012-2014 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.bind;
+
+import static org.hamcrest.Matchers.is;
+import static org.junit.Assert.assertThat;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.beans.factory.annotation.Value;
+import org.springframework.boot.bind.ConverterBindingTests.TestConfig;
+import org.springframework.boot.context.properties.ConfigurationProperties;
+import org.springframework.boot.context.properties.ConfigurationPropertiesBinding;
+import org.springframework.boot.context.properties.EnableConfigurationProperties;
+import org.springframework.boot.test.IntegrationTest;
+import org.springframework.boot.test.SpringApplicationConfiguration;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.context.support.PropertySourcesPlaceholderConfigurer;
+import org.springframework.core.convert.converter.Converter;
+import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
+
+/**
+ * Tests for {@link ConfigurationProperties} binding with custom converters.
+ *
+ * @author Dave Syer
+ */
+@RunWith(SpringJUnit4ClassRunner.class)
+@SpringApplicationConfiguration(TestConfig.class)
+@IntegrationTest("foo=bar")
+public class ConverterBindingTests {
+
+	@Value("${foo:}")
+	private String foo;
+
+	@Autowired
+	private Wrapper properties;
+
+	@Test
+	public void overridingOfPropertiesOrderOfAtPropertySources() {
+		assertThat(this.properties.getFoo().getName(), is(this.foo));
+	}
+
+	@Configuration
+	@EnableConfigurationProperties(Wrapper.class)
+	public static class TestConfig {
+
+		@Bean
+		@ConfigurationPropertiesBinding
+		public Converter<String, Foo> converter() {
+			return new Converter<String, ConverterBindingTests.Foo>() {
+
+				@Override
+				public Foo convert(String source) {
+					Foo foo = new Foo();
+					foo.setName(source);
+					return foo;
+				}
+			};
+		}
+
+		@Bean
+		public static PropertySourcesPlaceholderConfigurer propertySourcesPlaceholderConfigurer() {
+			return new PropertySourcesPlaceholderConfigurer();
+		}
+
+	}
+
+	public static class Foo {
+		private String name;
+
+		public String getName() {
+			return this.name;
+		}
+
+		public void setName(String name) {
+			this.name = name;
+		}
+
+	}
+
+	@ConfigurationProperties
+	public static class Wrapper {
+		private Foo foo;
+
+		public Foo getFoo() {
+			return this.foo;
+		}
+
+		public void setFoo(Foo foo) {
+			this.foo = foo;
+		}
+	}
+
+}