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https://issues.apache.org/jira/browse/SANDBOX-397?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Benedikt Ritter updated SANDBOX-397:
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Attachment: SANDBOX-397_SRP.txt
I have created another patch, that builds upon the first one. I think it is not
a responsibility of a {{DefaultBeanAccessor}} to figure out, whether or not
properties are available or not. So the private methods from the first patch
are a violation of SRP [1].
For this reason I created a new class, that is reponsible for handling
properties of a class: {{Properties<B>}}. I think this is a nice and clean
solution to the SRP violation. However the patch is incomplete, because several
unit tests fail (for details see below). I uploaded the patch anyway, because I
want to know, what you think about the hole idea, before I start to fix the
issues raised by the new class.
The reason for the failing tests is, that {{DefaultBeanAccessor}} creates a
{{Properties}} object in its constructor using the bean object passed in. A
{{DefaultBeanAccessor}} can be created in several ways:
* {{BeanUtils.on(B bean)}}
* {{ArgumentsAccessor.with(...)}}
If in the latter case, a method is invoked that returns void, instantiation of
{{DefaultBeanAccessor}} will fail, because the constructor tries to call
{{getClass()}} on {{null}}.
I think this is not a problem of the newly invented {{Properties<B>}} class,
but of {{ArgumentAccessor.with(...)}}. In other words, this was broken before
but we had no tests for this case.
A solution could be to write a Special Case [2] implementation of
{{BeanAccessor}} for this case ({{NullBeanAccessor}}) that will be returned by
{{ArgumentsAccessor.with(...)}} if a method returns void.
What do you think?
All the best,
Benedikt
[1] http://en.wikipedia.org/wiki/Single_responsibility_principle
[2] http://martinfowler.com/eaaCatalog/specialCase.html
> [BeanUtils2] Replace NullPointerExceptions been thrown in DefaultBeanAccessor
> with NoSuchMethodEceptions
> --------------------------------------------------------------------------------------------------------
>
> Key: SANDBOX-397
> URL: https://issues.apache.org/jira/browse/SANDBOX-397
> Project: Commons Sandbox
> Issue Type: Task
> Components: BeanUtils2
> Affects Versions: Nightly Builds
> Reporter: Benedikt Ritter
> Attachments: SANDBOX-397.txt, SANDBOX-397_SRP.txt
>
>
> At the moment, methods in {{DefaultBeanAccessor}} throw a
> {{NullPointerException}}, if no {{PropertyDescriptor}} for a given property
> name can be retrieved. As discussed on the ML (see
> http://markmail.org/thread/zlehclmybp5xgn5n) this behavior should be changed
> to throwing {{NoSuchMethodException}}.
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