Re: [TRINIDAD] public URLProvider API needed for TRINIDAD-1914

Jeanne Waldman Fri, 17 Sep 2010 14:30:40 -0700

Hi,
This is what I'm going to do:

1. Create a org.apache.myfaces.trinidad.resource.SkinResourceLoader class. I didn't want to use the current ResourceLoader because I thought that was too generic. I am loading these classes with the ClassLoaderUtils.getServices, and I didn't want to make it too generic.
1a. for now it won't extend anything. later we can extend ResourceLoader if we need to.
1b.

public Iterator<URL> findResources(ExternalContext context,
String filename)

  {

      return Collections.<URL>emptyList().iterator();

  }

2. usage in SkinUtils.java

    // register skins found in DT using the META-INF/services

    List<SkinResourceLoader> urlProviders =
ClassLoaderUtils.getServices(

                                     
"org.apache.myfaces.trinidad.resource.SkinResourceLoader");

Iterator<URL> urlIterator =
urlProvider.findResources(context, "trinidad-skins.xml");

Let me know if you have any objections.
Thanks,
Jeanne

Jeanne Waldman wrote, On 9/17/2010 8:42 AM PT:

Thanks Pavitra. see inline

Pavitra Subramaniam wrote, On 9/16/2010 7:24 PM PT:
On 9/13/2010 5:13 PM, Jeanne Waldman wrote:
Hi,

Today I created a new jira issue, https://issues.apache.org/jira/browse/TRINIDAD-1914 provide a hook for external decorator to find trinidad-skins.xml from a location other than META-INF or WEB-INF.

I have some questions I need help answering. I've listed them in the JIRA issue, but I'll reiterate here.

Our design time team needs a way to have the Trinidad Skinning Framework find trinidad-skins.xml from a location other than META-INF or WEB-INF.

The implementation I have in mind is similar to https://issues.apache.org/jira/browse/TRINIDAD-1729 provide a hook for for an external decorator of Skin InputStreamProvider.

I've mocked up a solution that works for our design time team. It is outlined below with questions.

1. Add a public API

public interface TrinidadSkinsURLProvider (name to be determined)
{
  // returns an Iterator of all the URLs that have this resource (trinidad-skins.xml)
  // Design time team needs the ExternalContext to be able to find their trinidad-skins.xml files.
  // They put a parameter on the ServletContext to help them.
  public Iterator<URL> findResources(ExternalContext context);
}

2. Usage in SkinUtils.java
  a. Call List<TrinidadSkinsURLProvider> urlProviders = ClassLoaderUtils.getServices(
                                      "org.apache.myfaces.trinidad.share.io.TrinidadSkinsURLProvider");
       to get the List of TrinidadSkinsURLProviders.
  b. Call findResources for each TrinidadSkinsURLProvider
  c. Call the existing trinidad-skins.xml parse code.

Questions

a. Is this idea acceptable?
b. Are there existing Trinidad APIs that I'm not aware of that I could use instead, like an existing ResourceLoader? org.apache.myfaces.trinidad.resource.ResourceLoader does not have a findResources method of any kind.

Could we add the findResources() method to this class and extend it (SkinsResourceLoader) rather than have a custom TrinidadSkinsURLProvider?

I was thinking this as well this morning, since it is a resource loader. Let me investigate more along these lines today. I'd like to not change existing code, so I'm wondering if I could add a SkinsResourceLoader that only has findResources(). Later we could extend an existing ResourceLoader - I'll see if this is possible.

c. Should we have a more generic class name, like URLProvider? Or URLResourceProvider? If so, then we can pass in the filename to findResources().

d. What package should this go in? My mockup is in org.apache.myfaces.trinidad.share.io.
e. ClassLoader#getResources returns an Enumeration<URL>. Should this new API be Iterator<URL> or should it match ClassLoader#getResources?

I would prefer an Iterator over Enumeration.

yes, me too. This is what I will do.

Thanks
Pavitra

Thanks,
Jeanne

Re: [TRINIDAD] public URLProvider API needed for TRINIDAD-1914

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