Usage question. Mapreduce with finalize
patb23 opened this issue · 1 comments
patb23 commented
Hi,
I have posted a question on Stackoverflow on how to use Finalize.
http://stackoverflow.com/questions/24723350/gmongo-mapreducer-with-finalizer
As explained in the post, was not able to use the mapreducecommand. Could I get help here?
Thanks
poiati commented
Hello patb23,
Sorry for my late response, here is a working example:
@Grab(group='com.gmongo', module='gmongo', version='1.2')
import com.gmongo.GMongo
import com.mongodb.MapReduceCommand
import com.mongodb.BasicDBObject
def mongo = new GMongo()
def db = mongo.getDB("gmongo")
def words = ['foo', 'bar', 'baz']
def rand = new Random()
db.words.drop()
1000.times {
db.words << [word: words[rand.nextInt(3)]]
}
assert db.words.count() == 1000
def map = """
function map() {
emit(this.word, {count: 1})
}
"""
def reduce = """
function reduce(key, values) {
var count = 0
for (var i = 0; i < values.length; i++)
count += values[i].count
return {count: count}
}
"""
def finalize = """
function finalize(key, reducedValue) {
return {count: reducedValue.count.toString()}
}
"""
def command = new MapReduceCommand(db.words, map, reduce, 'mrresult', MapReduceCommand.OutputType.REPLACE, new BasicDBObject())
command.setFinalize(finalize)
db.words.mapReduce(command)
println db.mrresult.findOne()
The finalize is just converting the count to a String
.