Overriding DocumentDefaultsDefinitions retrieval from root element attributes [SPR-6010]

[spring-projects-issues]

Tuomas Kiviaho opened SPR-6010 and commented

Currently DocumentDefaultsDefinition initialization seeks always the given root element attributes for default values. Overriding of the behavior requires creation and initialization of the DocumentDefaultsDefinition which is lazily created at BeanDefinitionParserDelegate.initDefaults(Element) method. Manual creation is impossible without reflection because the field where the default are held is private.

I propose that this field is made protected and/or construction of the default implementation is made along field the field declaration to help out overriding of the initDefaults method.

protected DocumentDefaultsDefinition defaults = new DocumentDefaultsDefinition();

More radical change would be altering the behaviour is binding the initialization to happen only when delegate.isDefaultNamespace(Element root) is true but this might have impact on custom implementations already out there so I guess this is completely out of the question.

---

Affects: 2.5.6

Referenced from: commits a805819

[spring-projects-issues]

Tuomas Kiviaho commented

Reflection is also needed to pull out original values of several fields that only have setters available at XmlBeanDefinitionReader.

[spring-projects-issues]

Juergen Hoeller commented

I've introduced a new template method for this purpose:

protected void populateDefaults(DocumentDefaultsDefinition defaults, Element root)

which allows for convenient overriding, with no need to access the underlying field directly.

What exactly are you trying to obtain from XmlBeanDefinitionReader that's not publicly accessible?

Juergen

[spring-projects-issues]

Tuomas Kiviaho commented

Thanks, leaving BeanDefinitionParserDelegate.defaults as null would break methods like ParserContext.isDefaultLazyInit() and initializing it from root element it only plausable for default namespace.

I couldn't find the fix for verification purposes. I presume I has been done to https://fisheye.springsource.org/browse/spring-framework/trunk/org.springframework.beans/src/main/java/org/springframework/beans/factory/xml/BeanDefinitionParserDelegate.java?r=HEAD but at the time of writing a method called 'populateDefaults' was missing. Normally Source tab contains direct links but last revision (2100) was from october and no #10678 tagged commits have been done so I guess this fix isn't in trunk.

---

Tuomas

[spring-projects-issues]

Juergen Hoeller commented

This is finally committed. The defaults field gets initialized with an empty DocumentDefaultsDefinition instance now right on construction of the containing delegate object.

You don't need to actually use the root element for deriving the default values. The template method just provides access to the root element for consideration (e.g. in its default implementation).

Juergen

[spring-projects-issues]

Tuomas Kiviaho commented

I can see it now. It's what I anticipated and I'm very pleased with it.

I consider this case closed (even without proposed delegate.isDefaultNamespace check at populateDefaults)

---

Tuomas