"adder" injection in addition to "setter" (invoke addXX() instead of setXX()) [SPR-2801]

[spring-projects-issues]

Endre Stølsvik opened SPR-2801 and commented

This request is similar to bug ##5727, "support "add"-style List injection", but suggests a more radical solution: Actual support for it in the spring beans xml-files: add-methods should be IoC-able in the same way as set-methods (and preferrably a mechanism to invoke any other method too, with any parameters).

As posted in:
http://forum.springframework.org/showthread.php?t=31058

quoting:
" Several types of "legacy beans" have "adder" methods for some properties instead of "setter" methods. This doesn't disqualify them from being handled as beans, I feel, but I can't figure out how I may invoke such a method in the same way as a property-setter? I have to be able to invoke such a method several times, obviously.. "

" I'd like to do this in spring's xml config, preferrably w/o a lot of hacks: I've come to understand that the org.springframework.beans.factory.config.MethodInvokingFactoryBean is the most cited approach to this problem, which I find on the edge of ridiculous.
I have this problem now with ActiveMQ, and I've had this problem with Jetty. Both have "addSomething": addConnector and addListener. "

" Jetty have its own style of "IoC" when it comes to configuration: in this file one may "code in XML" using <Call name="addListener"> and <New class=".."> (in addition to <Set name="...">). I know this isn't as clean as Spring, but at least one may get things done both with legacy and proper "IoC style" beans then.. "

Add elements to the bean element, something along the lines of:

<bean id="broker"
class="demo"
init-method="start"
destroy-method="stop">
<constructor-arg>
[ You know the deal ]
</constructor-arg>
<property name="setter">
[ You know the deal ]
</property>
<add-property name="adder">
[ Same semantics as ]
</add-property> [ multiple invocations to the same name must be allowed ]
<invoke name="someOtherMethod">
<argument>
[ Same semantics as ]
</argument> [ multiple invocations to the same name must be allowed ]
</invoke>
</bean>

There are hacks to overcome this, read the referred thread (using org.springframework.beans.factory.config.MethodInvokingFactoryBean w/o really using it!), but this is obviously a thing that comes up from time to time in the forums, and it would be great if such style of configuration was supported natively. (btw: At least jetty could possibly use spring instead of its own config parsing then!).

---

Affects: 2.0 final

Issue Links:

• Please improve BeanFactory support for containers & collections [SPR-230] #4961 Please improve BeanFactory support for containers & collections ("duplicates")

3 votes, 2 watchers

[spring-projects-issues]

Endre Stølsvik commented

Similar to improvement request #7222, which asks for "adder injection" based on the requirement of registering event listeners, which often are registered/injected in beans using addListener methods.

[spring-projects-issues]

Endre Stølsvik commented

Also similar to improvement request #5727, which points out "Some classes don't expose a plublic setter for internal list (as an example, commons-configuration CompositeConfiguration) bue some addXXX(item) method."

[spring-projects-issues]

Christopher Sahnwaldt commented

Maybe we don't need a new element like <add-property>, just a new attribute...
Something like this?

<bean id="eventBean">
<property name="X" ref="listener1" action="add"/>
<property name="X" ref="listener2" action="add"/>
</bean>

[spring-projects-issues]

Christopher Sahnwaldt commented

I just found #4961 which explains it all. This issue is basically a duplicate of #4961 .

[spring-projects-issues]

Dave Syer commented

Marked as duplicate of #4961