Development-Custom Resource Manager

Last modified by Pascal Robert on 2010/09/13 00:26

Petite Abeille

Here is a little example on how to write your own WOResourceManager:

The main methods to implement are urlForResourceNamed() and bytesForResourceNamed().

urlForResourceNamed simply build an URL for a resource from wherever you would like (eg a jar file). Unfortunately, urlForResourceNamed uses pathForResourceNamed so you will need to rewrite that also:

private URL urlForResourceNamed(String aResourceName)
{
  return this.getClass().getResource( aResourceName );
}

public String pathForResourceNamed(String aResourceName, String aFrameworkName, NSArray someLanguages)
{
  URL anURL = this.urlForResourceNamed( aResourceName );

  if ( anURL != null )
   {
    return anURL.toExternalForm();
   }

  return null;
}

public String urlForResourceNamed(String aResourceName, String aFrameworkName, NSArray someLanguages, WORequest aRequest)
{
  String anURL = super.urlForResourceNamed( aResourceName, aFrameworkName, someLanguages, aRequest );

  this.bytesForResourceNamed( aResourceName, aFrameworkName, someLanguages );

  return anURL;
}

bytesForResourceNamed simply retrieve a resource from wherever you would like (eg a jar file):

public InputStream inputStreamForResourceNamed(String aResourceName, String aFrameworkName, NSArray someLanguages)
{
  return this.getClass().getResourceAsStream( aResourceName );
}

public byte[] bytesForResourceNamed(String aResourceName, String aFrameworkName, NSArray someLanguages)
{
  if ( aResourceName != null )
   {
    URL anURL = this.urlForResourceNamed( aResourceName );

    if ( anURL != null )
     {
      String      aKey = anURL.toString();
      WOURLValuedElementData anElement = (WOURLValuedElementData) _cache.get( aKey );

      if ( anElement == null )
       {
        synchronized( this )
         {
          InputStream anInputStream = this.inputStreamForResourceNamed( aResourceName, null, null );

          if ( anInputStream != null )
           {
            try
             {
              InputStream aBufferStream = new BufferedInputStream( anInputStream );
              byte[]    someBytes = new byte[ aBufferStream.available() ];

              aBufferStream.read( someBytes );
              aBufferStream.close();
              anInputStream.close();

               {
                Data someData = new Data( someBytes );
                String aType = this.contentTypeForResourceNamed( aKey );

                anElement = new WOURLValuedElementData( someData, aType, aKey );

                _cache.put( aKey, anElement );
               }
             }
            catch(Exception anException)
             {
              SZLog.warning( anException );
             }
           }
         }
       }

      return ( (Data) anElement.data() ).bytesNoCopy();
     }

    SZLog.debug( "Null url for resource named '" + aResourceName + "'." );

    return null;
   }

  throw new IllegalArgumentException ( "ResourceManager.bytesForResourceNamed: null resource name." );
}

Last but not least, you need to take care of those funky WOURLValuedElementData so dataForResourceNamed will work:

public NSData dataForResourceNamed(String aResourceName)
{
  this.bytesForResourceNamed( aResourceName, null, null );

  String      aKey = this.urlForResourceNamed( aResourceName ).toString();
  WOURLValuedElementData anElement = (WOURLValuedElementData) _cache.get( aKey );

  return anElement.data();
}

Finally, you need to register your resource manager with WOApplication:

anApplication.setResourceManager( new ResourceManager() );

Handling of languages and frameworks are left as an exercise to the reader.