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From "Niall Pemberton" <niall.pember...@blueyonder.co.uk>
Subject Re: [beanutils] PropertyUtils & DynaBeans
Date Sat, 04 Dec 2004 05:39:22 GMT
Maybe you could spell out the issues with PropertyUtils and DynaBeans and
the methods involved and what you're trying to do because its not clear what
your trying to resolve.

I'm don't see much value in the getDynaProperties() method being in
PropertyUtils - all you need to do is make eveything a DynaBean then you can
get the DynaProperties and do whatever you want using the existing
DynaBean/DynaClass methods -  no need for PropertyUtils at all.

DynaBean dynaBean = (bean instanceof DynaBean)
            ? (DynaBean)bean : new WrapDynaBean(bean);

For caching to work people are going to have to change how they create
DynaBeans and I believe its better left up to the environment they're being
used in to implement a caching mechanism - Struts does this for its
DynaActionForm implementation.

Niall

----- Original Message ----- 
From: "Kris Nuttycombe" <Kris.Nuttycombe@noaa.gov>
To: "Commons Developers Jakarta" <commons-dev@jakarta.apache.org>
Sent: Saturday, December 04, 2004 12:55 AM
Subject: [beanutils] PropertyUtils & DynaBeans


> Hi, all,
>
> As it currently stands, PropertyUtils doesn't support DynaBeans for a
> number of its methods. It doesn't make much sense to return
> PropertyDescriptors for DynaBeans, but it's no great pain to use
> WrapDynaClass on an ordinary class and thereby be able to introspect
> either regular beans or DynaBeans using the same interface. To support
> this, I'd like to add a method with the signature:
>
> DynaProperty[] getDynaProperties(Object bean)
>
> to PropertyUtilsBean, with a corresponding static method in PropertyUtils.
>
> Now, one of the other advantages of using PropertyUtilsBean is that it
> caches the introspected data. Conceivably, this would also be a useful
> feature for the getDynaProperties method. However, here we have a
> problem: since DynaClass doesn't have any way to enforce that its
> implementations implement HashCode, there's no way to use the same map
> caching strategy as is used for the PropertyDescriptors. This
> illustrates a larger issue, which is that DynaClass objects aren't
> singletons like Class objects are.
>
> To resolve this, I propose adding an AbstractDynaClass base class that
> implements hashCode() and equals() based upon the public methods
> available in DynaClass. This way, even if DynaClasses aren't singletons,
> they can be used for hash keys. It might be also useful to implement a
> registry for DynaClasses in this abstract class to provide
> singleton-like functionality. Existing DynaClass implementations would
> be modified to extend AbstractDynaClass.
>
> Any thoughts?
>
> Kris



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