How to programmatically create bean definition with injected properties?

Question

I want to programmatically add a bean definition to an application context, but some properties of that definition are other beans from that context (I know their names). How can I do this so that those properties will be injected?

For example:

GenericBeanDefinition beanDef = new GenericBeanDefinition();
beanDef.setBeanClass(beanClass);

MutablePropertyValues values = new MutablePropertyValues();
values.addPropertyValue("intProperty", 10);
values.addPropertyValue("stringProperty", "Hello, world");
values.addPropertyValue("beanProperty", /* What should be here? */);

beanDef.setPropertyValues(values);

I'm using Spring 3.0.

Solution 1

Use RuntimeBeanReference:

values.addPropertyValue("beanProperty", new RuntimeBeanReference("beanName")); 

Solution 2

I would add a bean like this that has access to the applicationContext:

public class AppContextExtendingBean implements ApplicationContextAware{


    @Override
    public void setApplicationContext(ApplicationContext applicationContext) throws BeansException{

        AutowireCapableBeanFactory beanFactory = applicationContext.getAutowireCapableBeanFactory();

        // do it like this
        version1(beanFactory);

        // or like this
        version2(beanFactory);

    }

    // let spring create a new bean and then manipulate it (works only for singleton beans, obviously) 
    private void version1(AutowireCapableBeanFactory beanFactory){
        MyObject newBean = (MyObject) beanFactory.createBean(MyObject.class,AutowireCapableBeanFactory.AUTOWIRE_BY_TYPE, true);
        newBean.setBar("baz");
        newBean.setFoo("foo");
        newBean.setPhleem("phleem");
        beanFactory.initializeBean(newBean, "bean1");
    }

    // create the object manually and then inject it into the spring context
    private void version2(AutowireCapableBeanFactory beanFactory){
        MyObject myObject=new MyObject("foo","phleem");
        myObject.setBar("baz");
        beanFactory.autowireBean(myObject);
        beanFactory.initializeBean(myObject, "bean2");
    }


}

Solution 3

I found the solution. I have to use another BeanDefinition as a property, like this:

GenericBeanDefinition bd2 = new GenericBeanDefinition();
bd2.setBeanClass(Dependency.class);

GenericBeanDefinition bd1 = new GenericBeanDefinition();
bd1.setBeanClass(Component.class);

MutablePropertyValues values = new MutablePropertyValues();
values.addPropertyValue("dependency", bd2);

bd1.setPropertyValues(values);

Comments

[Fixpoint]

I can't use Javaconfig because I need to create these definitions dynamically. How can I use BeanDefinitionParser?

[Bozho]

javaconfig should do fine in all cases. Look at some implementations of BeanDefinitionParser to see how they work. (checkout the spring sources)

[Fixpoint]

Are there any differences with using a BeanDefinition as a property?

[axtavt]

@Shooshpanchick: BeanDefinition creates a new inner bean of the specified class, when RuntimeBeanReference creates a reference to the exisiting one.

[rayman]

Hi after lots of research I found your post and that worked fine. I am using version2. but tell me: using AutowireCapableBeanFactory would cost any memory leak or performances? thanks.

[rayman]

Hi, But how do you finally add the GenericBeanDefinition to the container?

[Mohammad Adnan]

This solution is seems to be fine. MyObject is seems to be a prototype bean(since we are creating objects from our own every time). do we need to provide any kind of annotation like @Component or @Scope? how spring decides to create it's scope?