setter-based injection in Spring Framework

[Ravi Kiran Va]

Hi , i am trying to learn setter Injection in Spring Framework . i have a class Person with property email .

public class Person {

	String email ;

	public String getEmail() {
		return email;
	}

	public void setEmail(String email) {
		this.email = email;
	}
	
}

<bean name="person" 
     class="examples.spring.Person">
     <property name="email">
          <value>[e-mail]</value>
     </property>
</bean>

I am getting confused here , using setter Injection only results in hard coding of values . Please anyone explain me this .

[Christophe Verré]

using setter Injection only results in hard coding of values .

Hard coding of values ? Can you explain what you are trying to ask ? Can you think of any theoretically better approach ?

[Ravi Kiran Va]

Thanks Christophe for responding .

what i mean to ask is that now the property email only consists of the value "[e-mail]" . so any time we call the getter method that will only produce this value now .

[Mark Spritzler]

Ravi Pavan wrote:Thanks Christophe for responding .

what i mean to ask is that now the property email only consists of the value "[e-mail]" . so any time we call the getter method that will only produce this value now .

Yes, that is 100% true. So the question is what setters are this ok to have only one value.

This is mostly for things like injecting a DAO into a Service class.

So if I have a service class, I won't want a property that holds state like say User first name. It is like using a Stateful Session Bean in ejb. I want all my services to be stateless. The only getters and setter that I would have in a Service class is injecting the DAOs that the Service needs, so example code here

   
public class OrderEntryServiceImpl implements OrderEntryService {
    private OrderDAO orderDao;

    public void setOrderDao(OrderDao orderDao) {
        this.orderDao = orderDao;
    }

    public Order searchScreen(SearchCriteria searchCriteria) {
        String customerNamer = searchCriteria.getCustomerName();
        return orderDao.findOrderByCustomerName(customerName);
    }
}

 

And always code to an interface never to an actual implementation class.

in my configuration I would create a bean for the DAO and a bean for the Service class and inject the DAO into the Service bean with the <property> tag.

Hope that makes things clearer. You would never have a Domain object defined as a Bean.

Mark

[Hong Anderson]

I'm still not sure what your question is, Ravi.
Could you please to give an example what are you trying to achieve?

[Christophe Verré]

I hope Mark's answer will help. I still can't figure out what your problem is.

[Ravi Kiran Va]

 You would never have a Domain object defined as a Bean.

Thanks Mark , this made me more clearer . You read my mind .