Support for @PropertySource annotations with custom implementation types

Issue: SPR-8963

spring-context/src/main/java/org/springframework/context/annotation/ConfigurationClassParser.java

@@ -66,7 +66,9 @@ import org.springframework.core.env.MutablePropertySources;
 import org.springframework.core.env.PropertySource;
 import org.springframework.core.io.Resource;
 import org.springframework.core.io.ResourceLoader;
+import org.springframework.core.io.support.DefaultPropertySourceFactory;
 import org.springframework.core.io.support.EncodedResource;
+import org.springframework.core.io.support.PropertySourceFactory;
 import org.springframework.core.io.support.ResourcePropertySource;
 import org.springframework.core.type.AnnotationMetadata;
 import org.springframework.core.type.MethodMetadata;
@@ -103,6 +105,8 @@ import org.springframework.util.StringUtils;
  */
 class ConfigurationClassParser {
 
+	private static final PropertySourceFactory DEFAULT_PROPERTY_SOURCE_FACTORY = new DefaultPropertySourceFactory();
+
 	private static final Comparator<DeferredImportSelectorHolder> DEFERRED_IMPORT_COMPARATOR =
 			new Comparator<ConfigurationClassParser.DeferredImportSelectorHolder>() {
 				@Override
@@ -355,15 +359,26 @@ class ConfigurationClassParser {
 	 */
 	private void processPropertySource(AnnotationAttributes propertySource) throws IOException {
 		String name = propertySource.getString("name");
+		if (!StringUtils.hasLength(name)) {
+			name = null;
+		}
 		String encoding = propertySource.getString("encoding");
+		if (!StringUtils.hasLength(encoding)) {
+			encoding = null;
+		}
 		String[] locations = propertySource.getStringArray("value");
-		boolean ignoreResourceNotFound = propertySource.getBoolean("ignoreResourceNotFound");
 		Assert.isTrue(locations.length > 0, "At least one @PropertySource(value) location is required");
+		boolean ignoreResourceNotFound = propertySource.getBoolean("ignoreResourceNotFound");
+
+		Class<? extends PropertySourceFactory> factoryClass = propertySource.getClass("factory");
+		PropertySourceFactory factory = (factoryClass == PropertySourceFactory.class ?
+				DEFAULT_PROPERTY_SOURCE_FACTORY : BeanUtils.instantiate(factoryClass));
+
 		for (String location : locations) {
 			try {
 				String resolvedLocation = this.environment.resolveRequiredPlaceholders(location);
 				Resource resource = this.resourceLoader.getResource(resolvedLocation);
-				addPropertySource(createPropertySource(name, encoding, resource));
+				addPropertySource(factory.createPropertySource(name, new EncodedResource(resource, encoding)));
 			}
 			catch (IllegalArgumentException ex) {
 				// from resolveRequiredPlaceholders
@@ -380,34 +395,23 @@ class ConfigurationClassParser {
 		}
 	}
 
-	private ResourcePropertySource createPropertySource(String name, String encoding, Resource resource) throws IOException {
+	private void addPropertySource(PropertySource<?> propertySource) {
-		if (StringUtils.hasText(name)) {
-			return (StringUtils.hasText(encoding) ?
-					new ResourcePropertySource(name, new EncodedResource(resource, encoding)) :
-					new ResourcePropertySource(name, resource));
-		}
-		else {
-			return (StringUtils.hasText(encoding) ?
-					new ResourcePropertySource(new EncodedResource(resource, encoding)) :
-					new ResourcePropertySource(resource));
-		}
-	}
-
-	private void addPropertySource(ResourcePropertySource propertySource) {
 		String name = propertySource.getName();
 		MutablePropertySources propertySources = ((ConfigurableEnvironment) this.environment).getPropertySources();
 		if (propertySources.contains(name) && this.propertySourceNames.contains(name)) {
 			// We've already added a version, we need to extend it
 			PropertySource<?> existing = propertySources.get(name);
+			PropertySource<?> newSource = (propertySource instanceof ResourcePropertySource ?
+					((ResourcePropertySource) propertySource).withResourceName() : propertySource);
 			if (existing instanceof CompositePropertySource) {
-				((CompositePropertySource) existing).addFirstPropertySource(propertySource.withResourceName());
+				((CompositePropertySource) existing).addFirstPropertySource(newSource);
 			}
 			else {
 				if (existing instanceof ResourcePropertySource) {
 					existing = ((ResourcePropertySource) existing).withResourceName();
 				}
 				CompositePropertySource composite = new CompositePropertySource(name);
-				composite.addPropertySource(propertySource.withResourceName());
+				composite.addPropertySource(newSource);
 				composite.addPropertySource(existing);
 				propertySources.replace(name, composite);
 			}

spring-context/src/main/java/org/springframework/context/annotation/PropertySource.java

@@ -23,6 +23,8 @@ import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;
 import java.lang.annotation.Target;
 
+import org.springframework.core.io.support.PropertySourceFactory;
+
 /**
  * Annotation providing a convenient and declarative mechanism for adding a
  * {@link org.springframework.core.env.PropertySource PropertySource} to Spring's
@@ -133,6 +135,7 @@ import java.lang.annotation.Target;
  * javadocs for details.
  *
  * @author Chris Beams
+ * @author Juergen Hoeller
  * @author Phillip Webb
  * @since 3.1
  * @see PropertySources
@@ -155,12 +158,6 @@ public @interface PropertySource {
 	 */
 	String name() default "";
 
-	/**
-	 * A specific character encoding for the given resources, e.g. "UTF-8".
-	 * @since 4.3
-	 */
-	String encoding() default "";
-
 	/**
 	 * Indicate the resource location(s) of the properties file to be loaded.
 	 * For example, {@code "classpath:/com/myco/app.properties"} or
@@ -184,4 +181,19 @@ public @interface PropertySource {
 	 */
 	boolean ignoreResourceNotFound() default false;
 
+	/**
+	 * A specific character encoding for the given resources, e.g. "UTF-8".
+	 * @since 4.3
+	 */
+	String encoding() default "";
+
+	/**
+	 * Specify a custom {@link PropertySourceFactory}, if any.
+	 * <p>By default, a default factory for standard resource files will be used.
+	 * @since 4.3
+	 * @see org.springframework.core.io.support.DefaultPropertySourceFactory
+	 * @see org.springframework.core.io.support.ResourcePropertySource
+	 */
+	Class<? extends PropertySourceFactory> factory() default PropertySourceFactory.class;
+
 }

spring-context/src/test/java/org/springframework/context/annotation/PropertySourceAnnotationTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2014 the original author or authors.
+ * Copyright 2002-2016 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.
@@ -17,8 +17,12 @@
 package org.springframework.context.annotation;
 
 import java.io.FileNotFoundException;
+import java.io.IOException;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
 import java.util.Collections;
 import java.util.Iterator;
+import java.util.Properties;
 import javax.inject.Inject;
 
 import org.junit.Rule;
@@ -27,9 +31,13 @@ import org.junit.rules.ExpectedException;
 
 import org.springframework.beans.factory.BeanDefinitionStoreException;
 import org.springframework.beans.factory.FactoryBean;
+import org.springframework.core.annotation.AliasFor;
 import org.springframework.core.env.Environment;
 import org.springframework.core.env.MapPropertySource;
 import org.springframework.core.env.MutablePropertySources;
+import org.springframework.core.io.support.EncodedResource;
+import org.springframework.core.io.support.PropertiesLoaderUtils;
+import org.springframework.core.io.support.PropertySourceFactory;
 import org.springframework.tests.sample.beans.TestBean;
 
 import static org.hamcrest.CoreMatchers.*;
@@ -111,6 +119,22 @@ public class PropertySourceAnnotationTests {
 		}
 	}
 
+	@Test
+	public void withCustomFactory() {
+		AnnotationConfigApplicationContext ctx = new AnnotationConfigApplicationContext();
+		ctx.register(ConfigWithImplicitName.class, WithCustomFactory.class);
+		ctx.refresh();
+		assertThat(ctx.getBean(TestBean.class).getName(), equalTo("P2TESTBEAN"));
+	}
+
+	@Test
+	public void withCustomFactoryAsMeta() {
+		AnnotationConfigApplicationContext ctx = new AnnotationConfigApplicationContext();
+		ctx.register(ConfigWithImplicitName.class, WithCustomFactoryAsMeta.class);
+		ctx.refresh();
+		assertThat(ctx.getBean(TestBean.class).getName(), equalTo("P2TESTBEAN"));
+	}
+
 	@Test
 	public void withUnresolvablePlaceholder() {
 		AnnotationConfigApplicationContext ctx = new AnnotationConfigApplicationContext();
@@ -354,6 +378,43 @@ public class PropertySourceAnnotationTests {
 	}
 
 
+	@Configuration
+	@PropertySource(value = "classpath:org/springframework/context/annotation/p2.properties", factory = MyCustomFactory.class)
+	static class WithCustomFactory {
+	}
+
+
+	@Configuration
+	@MyPropertySource(value = "classpath:org/springframework/context/annotation/p2.properties")
+	static class WithCustomFactoryAsMeta {
+	}
+
+
+	@Retention(RetentionPolicy.RUNTIME)
+	@PropertySource(value = {}, factory = MyCustomFactory.class)
+	public @interface MyPropertySource {
+
+		@AliasFor(annotation = PropertySource.class)
+		String value();
+	}
+
+
+	public static class MyCustomFactory implements PropertySourceFactory {
+
+		@Override
+		public org.springframework.core.env.PropertySource createPropertySource(String name, EncodedResource resource) throws IOException {
+			Properties props = PropertiesLoaderUtils.loadProperties(resource);
+			return new org.springframework.core.env.PropertySource<Properties>("my" + name, props) {
+				@Override
+				public Object getProperty(String name) {
+					String value = props.getProperty(name);
+					return (value != null ? value.toUpperCase() : null);
+				}
+			};
+		}
+	}
+
+
 	@Configuration
 	@PropertySource(
 			name = "psName",

spring-core/src/main/java/org/springframework/core/io/support/DefaultPropertySourceFactory.java

@@ -0,0 +1,39 @@
+/*
+ * Copyright 2002-2016 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.
+ * 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.core.io.support;
+
+import java.io.IOException;
+
+import org.springframework.core.env.PropertySource;
+
+/**
+ * The default implementation for {@link PropertySourceFactory},
+ * wrapping every resource in a {@link ResourcePropertySource}.
+ *
+ * @author Juergen Hoeller
+ * @since 4.3
+ * @see PropertySourceFactory
+ * @see ResourcePropertySource
+ */
+public class DefaultPropertySourceFactory implements PropertySourceFactory {
+
+	@Override
+	public PropertySource<?> createPropertySource(String name, EncodedResource resource) throws IOException {
+		return (name != null ? new ResourcePropertySource(name, resource) : new ResourcePropertySource(resource));
+	}
+
+}

spring-core/src/main/java/org/springframework/core/io/support/PropertySourceFactory.java

@@ -0,0 +1,41 @@
+/*
+ * Copyright 2002-2016 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.
+ * 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.core.io.support;
+
+import java.io.IOException;
+
+import org.springframework.core.env.PropertySource;
+
+/**
+ * Strategy interface for creating resource-based {@link PropertySource} wrappers.
+ *
+ * @author Juergen Hoeller
+ * @since 4.3
+ * @see DefaultPropertySourceFactory
+ */
+public interface PropertySourceFactory {
+
+	/**
+	 * Create a {@link PropertySource} that wraps the given resource.
+	 * @param name the name of the property source
+	 * @param resource the resource (potentially encoded) to wrap
+	 * @return the new {@link PropertySource} (never {@code null})
+	 * @throws IOException if resource resolution failed
+	 */
+	PropertySource<?> createPropertySource(String name, EncodedResource resource) throws IOException;
+
+}