Add @CloudScan annotation that registers services and application instance info beans

spring-cloud-spring-service-connector/src/main/java/org/springframework/cloud/config/CloudScanHelper.java

@@ -10,6 +10,7 @@ import org.springframework.beans.factory.support.BeanDefinitionBuilder;
 import org.springframework.beans.factory.support.BeanDefinitionRegistry;
 import org.springframework.cloud.Cloud;
 import org.springframework.cloud.CloudFactory;
+import org.springframework.cloud.app.ApplicationInstanceInfo;
 import org.springframework.cloud.config.java.ServiceScan;
 import org.springframework.cloud.service.GenericCloudServiceConnectorFactory;
 import org.springframework.cloud.service.ServiceInfo;
@@ -21,7 +22,7 @@ import org.springframework.cloud.service.ServiceInfo;
  *
  * Usage:
  * Most applications should use either the Java config using {@link ServiceScan} annotation 
- * or XML config using <cloud:service-scan/> that introduce a bean of this type lgically 
+ * or XML config using <cloud:service-scan/> that introduce a bean of this type logically 
  * equivalent to:
  * <pre>
  * &lt;bean class="org.cloudfoundry.runtime.service.CloudServicesScanner"/&gt;
@@ -44,9 +45,9 @@ import org.springframework.cloud.service.ServiceInfo;
  * @author Ramnivas Laddad
  *
  */
-public class ServiceScanHelper {
+public class CloudScanHelper {
     private static final String CLOUD_FACTORY_BEAN_NAME = "__cloud_factory__";
-    private static Logger logger = Logger.getLogger(ServiceScanHelper.class.getName());
+    private static Logger logger = Logger.getLogger(CloudScanHelper.class.getName());
     
     private Cloud cloud;
 
@@ -58,6 +59,17 @@ public class ServiceScanHelper {
             registerServiceBean(registry, serviceInfo);
         }
     }
+    
+    public void registerApplicationInstanceBean(BeanDefinitionRegistry registry) {
+        initializeCloud(registry);
+        
+        BeanDefinitionBuilder definitionBuilder = 
+                BeanDefinitionBuilder.genericBeanDefinition(ApplicationInstanceInfoWrapper.class);
+        definitionBuilder.addConstructorArgValue(cloud);
+        definitionBuilder.getRawBeanDefinition().setAttribute(
+                                  "factoryBeanObjectType", ApplicationInstanceInfo.class);
+        registry.registerBeanDefinition("spring.cloud.appplicationInstanceInfo", definitionBuilder.getBeanDefinition());
+    }
 
     private void initializeCloud(BeanDefinitionRegistry registry) {
         if (cloud != null) {
@@ -113,5 +125,27 @@ public class ServiceScanHelper {
         }
     }
 
+    public static class ApplicationInstanceInfoWrapper implements FactoryBean<ApplicationInstanceInfo> {
+        private Cloud cloud;
+        
+        public ApplicationInstanceInfoWrapper(Cloud cloud) {
+            this.cloud = cloud;
+        }
+        
+        @Override
+        public ApplicationInstanceInfo getObject() throws Exception {
+            return cloud.getApplicationInstanceInfo();
+        }
 
+        @Override
+        public Class<?> getObjectType() {
+            return ApplicationInstanceInfo.class;
+        }
+
+        @Override
+        public boolean isSingleton() {
+            return true;
+        }
+        
+    }
 }

spring-cloud-spring-service-connector/src/main/java/org/springframework/cloud/config/java/CloudScan.java

@@ -0,0 +1,63 @@
+package org.springframework.cloud.config.java;
+
+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.cloud.app.ApplicationInstanceInfo;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.context.annotation.Import;
+
+/**
+ * Add this annotation to an @{@link Configuration} class to have a bean for each
+ * service bound to the app as well as one for {@link ApplicationInstanceInfo} added to 
+ * the application context.
+ *
+ * <pre class="code">
+ * &#064;Configuration
+ * &#064;CloudScan
+ * public class CloudConfiguration {
+ *     // may (optionally) extend AbstractCloudConfiguration
+ * }
+ * </pre>
+ * 
+ * This annotation is similar to &#064;ComponentScan in Spring, which scans for classes
+ * with the &#064;Component classes and creates a bean for each. &#064;CloudScan, in the same
+ * spirit, scans services bound to the app and creates a bean for each. It also creates a bean
+ * of {@link ApplicationInstanceInfo} class to expose information about the application instance. 
+ * 
+ * Upon service scanning, if there is a unique bean of for service type, you can inject it 
+ * using the following code (shows Redis, but the same scheme works for all services):
+ * <pre>
+ * &#64;Autowired RedisConnectionFactory redisConnectionFactory;
+ * </pre>
+ *
+ * If there are more than one services of a type, you can use the &#064;Qualifier annotation
+ * as in the following code:
+ * <pre>
+ * &#64;Autowired &#64;Qualifier("service-name1") RedisConnectionFactory redisConnectionFactory;
+ * &#64;Autowired &#64;Qualifier("service-name2") RedisConnectionFactory redisConnectionFactory;
+ * </pre>
+ * 
+ * Similarly, application can have {@link ApplicationInstanceInfo} injected as follows:
+ * <pre> 
+ * &#64;Autowired ApplicationInstanceInfo applicationInstanceInfo;
+ * </pre>
+ *  
+ * Note the difference between &#64;{@link ServiceScan} and this annotation. While the former only
+ * adds beans for each bound service, the &#64;{@link CloudScan} annotation also adds a
+ * bean for {@link ApplicationInstanceInfo}.
+ * 
+ * @see ServiceScan 
+ * @author Ramnivas Laddad
+ *
+ */
+@Retention(RetentionPolicy.RUNTIME)
+@Target(ElementType.TYPE)
+@Documented
+@Import(CloudScanConfiguration.class)
+public @interface CloudScan {
+
+}

spring-cloud-spring-service-connector/src/main/java/org/springframework/cloud/config/java/CloudScanConfiguration.java

@@ -0,0 +1,25 @@
+package org.springframework.cloud.config.java;
+
+import org.springframework.beans.BeansException;
+import org.springframework.beans.factory.support.BeanDefinitionRegistry;
+import org.springframework.cloud.app.ApplicationInstanceInfo;
+import org.springframework.cloud.config.CloudScanHelper;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.core.type.AnnotationMetadata;
+
+/**
+ * Introduces beans for each bound service and one for {@link ApplicationInstanceInfo}
+ * 
+ * @author Ramnivas Laddad
+ * @see CloudScan
+ */
+@Configuration
+public class CloudScanConfiguration extends ServiceScanConfiguration {
+    private CloudScanHelper helper = new CloudScanHelper();
+    
+    @Override
+    public void registerBeanDefinitions(AnnotationMetadata importingClassMetadata, BeanDefinitionRegistry registry) throws BeansException {
+        super.registerBeanDefinitions(importingClassMetadata, registry);
+        helper.registerApplicationInstanceBean(registry);
+    }
+}

spring-cloud-spring-service-connector/src/main/java/org/springframework/cloud/config/java/ServiceScanConfiguration.java

@@ -2,7 +2,7 @@ package org.springframework.cloud.config.java;
 
 import org.springframework.beans.BeansException;
 import org.springframework.beans.factory.support.BeanDefinitionRegistry;
-import org.springframework.cloud.config.ServiceScanHelper;
+import org.springframework.cloud.config.CloudScanHelper;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.context.annotation.ImportBeanDefinitionRegistrar;
 import org.springframework.core.type.AnnotationMetadata;
@@ -15,7 +15,7 @@ import org.springframework.core.type.AnnotationMetadata;
  */
 @Configuration
 public class ServiceScanConfiguration implements ImportBeanDefinitionRegistrar {
-    private ServiceScanHelper helper = new ServiceScanHelper();
+    private CloudScanHelper helper = new CloudScanHelper();
     
     @Override
     public void registerBeanDefinitions(AnnotationMetadata importingClassMetadata, BeanDefinitionRegistry registry) throws BeansException {

spring-cloud-spring-service-connector/src/main/java/org/springframework/cloud/config/xml/CloudNamespaceHandler.java

@@ -6,7 +6,7 @@ import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
 import org.springframework.beans.factory.support.BeanDefinitionRegistry;
 import org.springframework.beans.factory.xml.AbstractSimpleBeanDefinitionParser;
 import org.springframework.beans.factory.xml.NamespaceHandlerSupport;
-import org.springframework.cloud.config.ServiceScanHelper;
+import org.springframework.cloud.config.CloudScanHelper;
 import org.w3c.dom.Element;
 
 /**
@@ -47,7 +47,7 @@ public class CloudNamespaceHandler extends NamespaceHandlerSupport {
 	}
 	
 	public static class ServiceScanBeanFactoryProcessor implements BeanFactoryPostProcessor {
-	    private ServiceScanHelper helper = new ServiceScanHelper();
+	    private CloudScanHelper helper = new CloudScanHelper();
 	    
 	    @Override
 	    public void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory) throws BeansException {

spring-cloud-spring-service-connector/src/test/java/org/springframework/cloud/config/java/CloudScanJavaConfigTest.java

@@ -0,0 +1,35 @@
+package org.springframework.cloud.config.java;
+
+import static org.junit.Assert.assertNotNull;
+
+import org.junit.Test;
+import org.springframework.cloud.app.ApplicationInstanceInfo;
+import org.springframework.cloud.config.AbstractCloudConfigServiceScanTest;
+import org.springframework.cloud.service.ServiceInfo;
+import org.springframework.context.ApplicationContext;
+import org.springframework.context.annotation.Configuration;
+
+/**
+ * Test for the {@link CloudScan} annotation
+ * 
+ * @author Ramnivas Laddad
+ *
+ */
+public class CloudScanJavaConfigTest extends AbstractCloudConfigServiceScanTest {
+	protected ApplicationContext getTestApplicationContext(ServiceInfo... serviceInfos) {
+		return getTestApplicationContext(CloudScanJavaConfigTestConfig.class, serviceInfos);
+	}
+	
+	@Test
+    public void cloudScanIntroducesApplicationInstanceInfo() {
+        ApplicationContext testContext = getTestApplicationContext();
+        
+        assertNotNull(testContext.getBean(ApplicationInstanceInfo.class));
+    }
+}
+
+@Configuration
+@CloudScan
+class CloudScanJavaConfigTestConfig {
+	
+}