LookupOverride only works for methods with no arguments [SPR-3017]

[spring-projects-issues]

Dave Syer opened SPR-3017 and commented

Actually it used to work before 2.0, but now there is an explicit check in LookupOverride.matches. I can see why it is there sort of, but if there are no overloaded methods and only one matches and it happens to have some arguments, why shouldn't it match?

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Affects: 2.0.1

1 votes, 0 watchers

[spring-projects-issues]

Dave Syer commented

A workaround is to use a MethodOverride instead of a LookupOverride - you just have to implement the MethodReplacer to return the bean that you want. E.g.

<bean id="bean" class="test.TestBean">
<replaced-method name="getFoo" replacer="replacer"/>
</bean>

<bean id="replacer" class="test.TestReplacer>
<property name="bean" ref="replaced"/>
</bean>

<bean id="replaced" class="test.Foo"/>

[spring-projects-issues]

Juergen Hoeller commented

I would argue that lookup-methods are not intended to have arguments in the first place: What's the point in accepting/passing in an argument and then ignoring it, performing a straight lookup for a specific bean by name? If we supported that, we'd need to do something with the arguments...

The present 2.0 implementation is clear and intuitive, I think, and allows for seamless adding of overloaded variants of the lookup method which may be implemented in a traditional fashion - without suddenly making the lookup-method tag fail or behave differently.

Furthermore, note that the documentation already indicated a no-arg requirement for lookup methods. It was just that the implementation didn't enforce that, assuming that there would be only only a single, non-overloaded no-arg method in the first place.

As for the MethodReplacer solution: A MethodReplacer is a generic callback which allows for full access to the arguments, so if a MethodReplacer implementation decides to ignore those, then that's its decision. The "lookup-method" support is simply more 'special purpose' in that respect, implying a no-arg method.

Juergen