Doc: Update ComponentBeanDefinitionParser example to work with nested child Components [SPR-3709]

[spring-projects-issues]

Brett Randall opened SPR-3709 and commented

The example of custom XML extensions described in Spring Reference Appendix B - "B.7. Meatier examples" could be improved.

The XML schema for foo:component allows for nesting of components to an arbitrary depth, i.e. component with child components that themselves cotain child components, and so on.

The sample ComponentBeanDefinitionParser in the documentation cannot deal with more than a single level of nested components, and so cannot effectively create all beans describable by the schema. Unit tests to retrieve a grandchild component of the top-level component fail.

The sample can be improved by making child component bean-processing recursive, allowing for nesting to any depth. This is achieved by composing child Component-s using their own ComponentFactoryBean.

Code to follow.

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Affects: 2.0.6

Attachments:

• FooComponentTest.zip (701.17 kB)

Referenced from: commits 1bbe93e

[spring-projects-issues]

Brett Randall commented

Improved sample code.

[spring-projects-issues]

Costin Leau commented

I just checked the documentation from Spring 3 and the example seems to be up to date.

[spring-projects-issues]

Brett Randall commented

I couldn't see any evidence in 2.5 CVS, 3.0 SVN or published http://static.springsource.org/spring/docs/3.0.x/spring-framework-reference/html/extensible-xml.html#extensible-xml-parser where the example has been updated. Is the commit revision number available? I suspect that this hasn't changed.

Perhaps for this example, adding the recursive processing is too detailed/complex, but I believe it is needed in order to be able to truly process documents following that schema fully i.e. nested child component-s to any depth. The current example does not recursively call parseChildComponents(...).

<foo:component id="parent" name="Parent">
	<foo:component id="child" name="Child">
		<foo:component id="grandchild" name="Grandchild">
			<foo:component id="greatgrandchild" name="Great Grandchild">
				<foo:component id="greatgreatgrandchild" name="Great Great Grandchild" />
			</foo:component>
		</foo:component>
	</foo:component>
</foo:component>

[spring-projects-issues]

Costin Leau commented

Brett, you're right - I checked only the first half of the class and missed the recursive parseComponent() call. I've reopened the issue and plan to address it shortly.
Thanks for checking it.

[spring-projects-issues]

Costin Leau commented

Brett, I've updated the doc and included a copy of the working example in trunk as well (tests included). See the source tab for more information.