Inject spring dependency in abstract super class

Question

I have requirement to inject dependency in abstract superclass using spring framework.

class A extends AbstractClassB{ 
    private Xdao daox ;
    ...
    public setXdao() { ... }
}

class AbstractClassB{
    ..
    private yDao  daoy;
    public seyYdao() { ... }
}

I need to pass superclass dependency everytime i instantiate Abstract class B (which can be subclassed in 100's of ways in my project)

entry in application.xml (spring context file)

<bean id="aClass" class="com.mypro.A" 
    <property name="daox" ref="SomeXDaoClassRef" /> 
    <property name="daoy" ref="SomeYDaoClassRef"/>
</bean>

How can i just create bean reference of super class AbstractClassB in application.xml so that i can use it in all subclass bean creation?

score 37 · Answer 1 · edited Aug 30 '13 at 07:10

You can create an abstract bean definition, and then "subtype" that definition, e.g.

<bean id="b" abstract="true" class="com.mypro.AbstractClassB">
    <property name="daox" ref="SomeXDaoClassRef" /> 
</bean>

<bean id="a" parent="b" class="com.mypro.A">
    <property name="daoy" ref="SomeYDaoClassRef" /> 
</bean>

Strictly speaking, the definition for b doesn't even require you to specify the class, you can leave that out:

<bean id="b" abstract="true">
    <property name="daox" ref="SomeXDaoClassRef" /> 
</bean>

<bean id="a" parent="b" class="com.mypro.A">
    <property name="daoy" ref="SomeYDaoClassRef" /> 
</bean>

However, for clarity, and to give your tools a better chance of helping you out, it's often best to leave it in.

Section 3.7 of the Spring Manual discusses bean definition inheritance.

If my parent class is not abstract and it is concrete class then still is this valid by ignoring abstract=true in the parent and declaring only parent at child..? — Kanagavelu Sugumar, May 10 '17 at 16:07

peakit · Answer 2 · 2013-03-27T15:12:52.833

4

You can use the abstract flag of Spring to tell Spring that a class is abstract. Then all concrete implementations can simply mark this bean as their parent bean.

<bean id="abstractClassB" class="AbstractClassB" abstract="true">
  <property name="yDao" ref="yDao" />
</bean>

<bean id="classA" class="A" parent="abstractClassB">
  <property name="xDao" ref="xDao" />
</bean>

edited Mar 27 '13 at 15:12

answered Nov 21 '10 at 16:55

peakit

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You mean `parent` instead of `extends` perhaps? – Muhd Mar 26 '13 at 22:01

score 2 · Answer 3 · answered Nov 21 '10 at 16:51

2

Have an abstract parent bean:

http://forum.springsource.org/showthread.php?t=55811

answered Nov 21 '10 at 16:51

duffymo

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Inject spring dependency in abstract super class

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