[Springframework-developer] Re: feature request

[Crater, J. \(EDS\) <Jon...@me...>]

Thanks for your reply.  I wasn't aware of the various factory bean
classes you mentioned, so this thread has already been useful.  What I
really need, though, is the ability to override the default Map/List/Set
implementation class on an as-needed basis.  So, for example, one of the
properties of one of my Spring-managed beans is a Map that needs to
retain the order in which it's configured, so I'd like to inject an
instance of SequencedHashMap, but I don't have a way to do that without
extensions.  Using a MapFactoryBean won't help me in this case because
the order will not be preserved, as the source map is required to have
been created.
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In another case, I may need to inject an instance of LinkedList, etc.
So, I don't want to override every single one, just the ones where my
needs diverge from what is built-in.  If a "type" attribute isn't
justified, is there another way?
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 Actually, this can already be achieved through using MapFactoryBean,
 ListFactoryBean and SetFactoryBean, respectively - passing a source
<map> /
 <list> / <set> in and specifying the desired "targetMapClass" /
 "targetListClass" / "targetSetClass".
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 I don"t see much advantage in a "type" attribute on the corresponding
tags
 directly, actually. It"s not that common to override the collection
 implementations on a per-collection basis to justify a special shortcut
for
 this, IMO.
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 Or are you trying to centrally override the default Map / List / Set
 implementations that Spring uses for <map> / <list> / <set>? Specifying
 those implementation classes _once_ rather than repeating them for
every
 single collection definition?
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 Juergen
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 ________________________________
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 From: springframework-developer-admin@li...
 [mailto:springframework-developer-admin@li...] On Behalf Of
 Crater, Jon (EDS)
 Sent: Tuesday, July 19, 2005 5:34 PM
 To: springframework-developer@li...
 Subject: [Springframework-developer] feature request
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 i currently have a need to customize the implementation classes created
when
 spring parses the definitions for properties containing <map>, <list>,
etc.
 elements.  currently i have to subclass AbstractXmlApplicationContext
and
 override initBeanDefinitionReader(XmlBeanDefinitionReader r) to call
 setParserClass(Class c) with my own subclass of BeanDefinitionParser,
which
 in turn overrides parseMapElement, etc.  i was hoping that future
releases
 of spring could support this situation via out of the box
configuration.  it
 seems like it would be fairly straightforward to respect a "type"
attribute
 of the <map> and <list> (and any other) elements to support
customization of
 the Map/Collection implementation without requiring custom extensions.
 =20
 if there"s sufficient interest, i"d be happy to contribute.
 =20
 jon