mapreduce - Morphia/MongoDB: ordering search results from advanced queries -

i'm new morphia, mongodb, , document-oriented databases in general. i'm looking general guidance on how approach following problem.

we have db around 500k book documents.

{     "isbn" : "0-691-01305-5",     "title" : "for whom bell tolls",     "titlefts" : [        "bell",        "toll" ],    "author" : "hemingway, ernest",    "ratingscount" : 138,     "rating" : "3.5",     "sales" : 10245    "price" : "12.95",     "category" : "fiction",     "description" : "the story of young american in international brigades attached republican guerilla unit during spanish civil war.",    "descriptionfts" : [        "story",        "young",        "americ",        "internat",        "brigade",        "attach",        "republic",        "guerilla",        "unit",        "spanish",        "civil",        "war"] } 

we need perform full-text searches on title , description fields. end, have created titlefts , descriptionfts arrays contains words title , description fields respectively, filtered of stop words, , stemmed.

when searching, users enter keywords, , return books match of entered terms, e.g.:

db.book.find({ titlefts : { $all: ['spanish', 'civil', 'war']}}) db.book.find({ descriptionfts : { $all: ['spanish', 'civil', 'war']}}) 

this works fine, but come tough part: we'd order results above queries based on multiple criteria. 1 such proposed ordering following:

1. books matching search terms in both titlefts , descriptionfts fields
2. books matching in titlefts field
3. books matching in descriptionfts field
4. books greatest # of sales
5. books highest rating
6. books highest ratingscount

our app written in java , uses morphiadb api. can envision how write java comparator sort of thing pretty easily, i'd ordering @ db level.

which brings me question: can done using morphia api? or need delve writing javascript db.command()? require map/reduce? if so, hint how implement map/reduce problem lot.

i recommend external fulltext engine solr or elasticsearch. capabilities of mongodb related fulltext search truely not suitable real fulltext solution. approach pre-stemming etc. dirty workaround. long mongodb not provide suitable fulltext integration, go external solution if interested in serious , working solution.