Extracting Values from a Custom Object Field - Velocity Token

Ed, I'd use an extensible approach like so:

## Set up your map of products to related asset(s)
#set( $assetsByProduct = {
  "product1|product2|product3" : {
    "banner" : "BannerA.jpg"
  },
  "product4|product5" : {
    "banner" : "BannerB.jpg"
  },
  "product6|product7|product8" : {
    "banner" : "BannerC.jpg"
  },
  "" : {
    "banner" : "DefaultBanner.gif"
  }
} )
##
## Start w/default asset set (empty key)
#set( $assets = $assetsByProduct[""] )
##
## Guard against bad inputs (null or empty object list)
#if( $ProductInterestList && !$ProductInterestList.isEmpty() )
    ##
    ## Loop backwards through objects (standard foreach is fwd only)
    #foreach( $idx in [$math.sub($ProductInterestList.size(),1)..0] )
        #set( $interest = $ProductInterestList[$idx] )
        #foreach( $assetSet in $assetsByProduct.keySet() )
            ##
            ## If we find a regex match for [map key,ProductName] we're done
            #if( $interest.ProductName.matches("(?i)${assetSet}") )
                #set( $assets = $assetsByProduct[$assetSet] )
                #break($foreach.parent)
            #end
        #end
    #end
#end
<img src="http://www.example.com/rs/${assets.banner}">

It's actually very simple logic, but Velocity is wordy (the same concept in JS would be half as long, for example there you have Array#reverse() while in VTL that doesn't exist as a built-in function).

The gist is:

• set up a mapping object that pairs product(s) with their banner images; use a default key ("") for when there's no match
• scan all the lead's ProductInterest objects -- from last to the first
• as soon as you get a pattern match, that's where you get your banner

It's extensible because you can add any other ProductInterest-specific data you want -- not just the "banner" property, but any other data that goes with the product. The $assetsByProduct map could be in its own script token for modularity.

Note the code uses a naive ordering to loop backward through the custom objects by index. You might want to sort them by some other property.

Final note: I added tabs for visual clarity. You'll want to delete them from your token (whitespace in Velocity doesn't disappear on its own, you may recall from other posts).