[Yanel-dev] policy viewer refactoring (inside "policymanager" resource-type)

[Guillaume Déflache]

Michael Wechner schrieb:
> Guillaume Déflache wrote:
>> Hi!
>>
>> For a project I need to implement some specific behaviour for the 
>> policy viewer.
>> So as to also reuse existing Yanel code for other unchanged things I'd 
>> need to be able to reuse parts of the existing Yanel implementation.
>>
>>
>> ATM alas the policy viewer is implemented by calling the sole static 
>> method PolicyViewer#getXHTMLView(PolicyManager pm, GroupManager gm, 
>> String path, String contentItemId, [other view options' parameters]) 
>> which does not allow any kind of overriding.
>>
>>
>> I'd like to introduce the following method in 
>> org.wyona.yanel.impl.resources.policymanager.PolicyManagerResource:
>>
>>     protected PolicyViewer getPolicyViewer(PolicyManager pm, 
>> GroupManager gm, [other view options' parameters]);
>>
>> with the visible API of PolicyViewer being:
>>
>>     InputStream getXHTMLInputStream(String path, String contentItemId) 
>> throws Exception
>>
>> Then I would be able to just change the used resource-type in 
>> $MY_SPECIFIC_REALM_DIR/src/webapp/global-resource-configs/policy-manager_yanel-rc.xml 
>> to one using my own PolicyViewer-based Java class!
>>
>> WDYT?
> 
> What exactly would you like to do?

The 1st thing I would like to do is to able to use the existing 
PolicyManagerResource as it is now, except I'd like to replace the 
PolicyViewer by another project-specific class, possibly reusing some 
parts of Yanel's original PolicyViewer implementation at a later stage.


> The reason I am asking is because I think "overriding/inheritance" is 
> not always a good thing and maybe it's better to introduce
> appropriate interfaces.

I do suggest introducing an API when I write "the visible API of 
PolicyViewer", even if in this 1st step it would not be a Java interface 
per se.
But indeed we should introduce a PolicyViewerV1 Java interface at some 
point, except for now I am not 100% sure if what I suggest is sufficient 
even for my own needs and if I would not need a finer-grained one later 
on. So I'd rather use a class than an interface at this point to avoid 
setting it in stone too early.


Hope this clears things a bit.

Cheers,
    Guillaume