[Dubbo-5049]support annotation config id property to be a alias for a config bean. Fixes apache#5049 (apache#5063)

LGTM

Author: sonymoon

dubbo-config/dubbo-config-spring/src/main/java/org/apache/dubbo/config/spring/beans/factory/annotation/DubboConfigBindingBeanPostProcessor.java

@@ -17,6 +17,7 @@
 package org.apache.dubbo.config.spring.beans.factory.annotation;
 
 import org.apache.dubbo.common.utils.Assert;
+import org.apache.dubbo.common.utils.StringUtils;
 import org.apache.dubbo.config.AbstractConfig;
 import org.apache.dubbo.config.spring.context.annotation.DubboConfigBindingRegistrar;
 import org.apache.dubbo.config.spring.context.annotation.EnableDubboConfigBinding;
@@ -29,6 +30,10 @@
 import org.springframework.beans.BeansException;
 import org.springframework.beans.factory.InitializingBean;
 import org.springframework.beans.factory.config.BeanPostProcessor;
+import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
+import org.springframework.beans.factory.support.BeanDefinitionRegistry;
+import org.springframework.beans.factory.support.BeanDefinitionRegistryPostProcessor;
+import org.springframework.beans.factory.support.DefaultListableBeanFactory;
 import org.springframework.context.ApplicationContext;
 import org.springframework.context.ApplicationContextAware;
 import org.springframework.core.annotation.AnnotationAwareOrderComparator;
@@ -49,7 +54,8 @@
  * @since 2.5.8
  */
 
-public class DubboConfigBindingBeanPostProcessor implements BeanPostProcessor, ApplicationContextAware, InitializingBean {
+public class DubboConfigBindingBeanPostProcessor implements BeanPostProcessor, ApplicationContextAware, InitializingBean
+        , BeanDefinitionRegistryPostProcessor {
 
     private final Log log = LogFactory.getLog(getClass());
 
@@ -67,6 +73,8 @@ public class DubboConfigBindingBeanPostProcessor implements BeanPostProcessor, A
 
     private ApplicationContext applicationContext;
 
+    private BeanDefinitionRegistry beanDefinitionRegistry;
+
     private boolean ignoreUnknownFields = true;
 
     private boolean ignoreInvalidFields = true;
@@ -145,6 +153,15 @@ public void setDubboConfigBinder(DubboConfigBinder dubboConfigBinder) {
 
     @Override
     public Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException {
+        if (bean instanceof AbstractConfig) {
+            String id = ((AbstractConfig) bean).getId();
+            if (beanDefinitionRegistry != null && beanDefinitionRegistry instanceof DefaultListableBeanFactory) {
+                DefaultListableBeanFactory factory = (DefaultListableBeanFactory) beanDefinitionRegistry;
+                if (!StringUtils.isBlank(id) && !factory.hasAlias(beanName, id)) {
+                    beanDefinitionRegistry.registerAlias(beanName, id);
+                }
+            }
+        }
         return bean;
     }
 
@@ -203,4 +220,15 @@ protected DubboConfigBinder createDubboConfigBinder(Environment environment) {
         return defaultDubboConfigBinder;
     }
 
+    @Override
+    public void postProcessBeanDefinitionRegistry(BeanDefinitionRegistry registry) throws BeansException {
+        if (this.beanDefinitionRegistry == null) {
+            this.beanDefinitionRegistry = registry;
+        }
+    }
+
+    @Override
+    public void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory) throws BeansException {
+        //do nothing here
+    }
 }

dubbo-config/dubbo-config-spring/src/test/java/org/apache/dubbo/config/spring/beans/factory/annotation/DubboConfigBindingBeanPostProcessorTest.java

@@ -17,6 +17,7 @@
 package org.apache.dubbo.config.spring.beans.factory.annotation;
 
 import org.apache.dubbo.config.ApplicationConfig;
+import org.apache.dubbo.config.ProtocolConfig;
 import org.apache.dubbo.config.spring.context.config.NamePropertyDefaultValueDubboConfigBeanCustomizer;
 import org.apache.dubbo.config.spring.context.properties.DefaultDubboConfigBinder;
 
@@ -52,6 +53,14 @@ public ApplicationConfig applicationConfig() {
         return new ApplicationConfig();
     }
 
+    @Bean("dubbo-demo-protocol")
+    public ProtocolConfig protocolConfig() {
+        ProtocolConfig protocolConfig = new ProtocolConfig();
+        protocolConfig.setName("dubbo");
+        protocolConfig.setId("customConfigAlias");
+        return protocolConfig;
+    }
+
     @Bean
     public DubboConfigBindingBeanPostProcessor bindingBeanPostProcessor() {
         return new DubboConfigBindingBeanPostProcessor("dubbo.application", "dubbo-demo-application");
@@ -65,8 +74,15 @@ public void test() {
 
         ApplicationConfig applicationConfig = applicationContext.getBean(ApplicationConfig.class);
 
+        String[] aliases = applicationContext.getAliases("dubbo-demo-protocol");
+        ProtocolConfig protocolConfigByName = applicationContext.getBean("dubbo-demo-protocol", ProtocolConfig.class);
+        ProtocolConfig protocolConfigById = applicationContext.getBean(protocolConfigByName.getId(), ProtocolConfig.class);
+
         Assert.assertEquals("dubbo-demo-application", applicationConfig.getName());
         Assert.assertEquals("mercyblitz", applicationConfig.getOwner());
         Assert.assertEquals("Apache", applicationConfig.getOrganization());
+
+        Assert.assertArrayEquals(new String[]{"customConfigAlias"}, aliases);
+        Assert.assertEquals(protocolConfigByName, protocolConfigById);
     }
 }