Spring Framework - ImportBeanDefinitionRegistrar Examples

package com.logicbig.example;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.support.BeanDefinitionRegistry;
import org.springframework.beans.factory.support.GenericBeanDefinition;
import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.*;
import org.springframework.core.type.AnnotationMetadata;

public class ImportBeanDefinitionRegistrarExample {

    public static void main (String[] args) {
        ApplicationContext context =
                  new AnnotationConfigApplicationContext(
                            MyConfig.class);
        ClientBean bean = context.getBean(ClientBean.class);
        bean.doSomething();
    }

    @Configuration
    @Import(MyBeanRegistrar.class)
    public static class MyConfig {

        @Bean
        ClientBean clientBean () {
            return new ClientBean();
        }
    }


    private static class MyBeanRegistrar implements ImportBeanDefinitionRegistrar {

        @Override
        public void registerBeanDefinitions (AnnotationMetadata importingClassMetadata,
                                             BeanDefinitionRegistry registry) {
            GenericBeanDefinition gbd = new GenericBeanDefinition();
            gbd.setBeanClass(AppBean.class);
            gbd.getPropertyValues().addPropertyValue("str", "value set from registrar");
            registry.registerBeanDefinition("appBean", gbd);
        }
    }

    private static class ClientBean {
        @Autowired
        private AppBean appBean;

        public void doSomething () {
            appBean.process();
        }
    }

    private static class AppBean {
        private String str;

        public void setStr (String str) {
            this.str = str;
        }

        public void process () {
            System.out.println(str);
        }
    }
}