Spring Lookup method injection not working
I am trying to achieve lookup method injection using a simple example. But, seems to fail in getting the bean injected via the method.
I have a simple bean namely; DemoBean as below:
public class DemoBean {
private String message;
public DemoBean() {
}
public DemoBean(String message) {
this.message = message;
}
// Getter and Setter methods
@Override
public String toString() {
return "DemoBean{" +
"message='" + message + ''' +
'}';
}
}
I am trying to inject DemoBean into another bean namely; PropertyBean:
public abstract class PropertyBean {
private DemoBean bean;
private String message;
// other members...
public PropertyBean(String message) {
this.message = message;
}
// Getter and Setter methods...
// Method for lookup injection
protected abstract DemoBean createBean();
@Override
public String toString() {
return "PropertyBean{" +
"bean=" + bean.toString() +
", message='" + message + ''' +
", number=" + number +
'}';
}
}
Noe, there is my beans configuration:
<bean id="demobean" class="aro.discoverspring.beans.DemoBean" scope="prototype">
<property name="message" value="The Default Message!!!" />
</bean>
<bean id="propertybean" class="aro.discoverspring.beans.PropertyBean">
<constructor-arg name="message" value="A message in PropertyBean"/>
<lookup-method name="createBean" bean="demobean" />
</bean>
When try to create an instance of PropertyBean . I am able to do so. But when I do the following.. I get null pointer exception on the DemoBean property (Because the bean is not getting injected!!)
PropertyBean pb = (PropertyBean) ctx.getBean("propertybean");
System.out.println(pb.toString());
What am I doing wrong? Did I miss anything or am I overlooking something silly there!? Spring 3.0 reference (section 3.4.6.1) seems to be doing the same.
bean property shouldn't be injected. As I understand spring implements createBean method for you, so when you call pb.createBean() it should return instance of DemoBean . But you don't assign anything to bean property in ProperyBean so there is no way for it to be not null.