Goal

The goal of this project is to provide a more simple, easy to use and less verbose API to work with mongodb using the Groovy programming language.

More information can be found here: http://blog.paulopoiati.com.

Support

Any bug, suggestion or ... whatever.

Email: paulogpoiati@gmail.com

Twitter: http://twitter.com/poiati

Maven

All versions of the project can be found in the maven central repository:

http://repo1.maven.org/maven2/com/gmongo/gmongo/

Usage

com.gmongo.GMongo doesn't extends com.mongodb.Mongo. It delegate all methods calls to a Mongo instance. If you need to get the Mongo reference �just call com.gmongo.GMongo#getMongo.

Sample:

// To download GMongo on the fly and put it at classpath
@Grab(group='com.gmongo', module='gmongo', version='0.9.5')
import com.gmongo.GMongo
// Instantiate a com.gmongo.GMongo object instead of com.mongodb.Mongo
// The same constructors and methods are available here
def mongo = new GMongo()

// Get a db reference in the old fashion way
def db = mongo.getDB("gmongo")

// Collections can be accessed as a db property (like the javascript API)
assert db.myCollection instanceof com.mongodb.DBCollection
// They also can be accessed with array notation 
assert db['my.collection'] instanceof com.mongodb.DBCollection

// Insert a document
db.languages.insert([name: 'Groovy'])
// A less verbose way to do it
db.languages.insert(name: 'Ruby')
// Yet another way
db.languages << [name: 'Python']

// Insert a list of documents
db.languages << [[name: 'Javascript', type: 'prototyped'], [name: 'Ioke', type: 'prototyped']]

def statics = ['Java', 'C', 'VB']

statics.each {
    db.languages << [name: it, type: 'static']
}

// Finding the first document
def lang = db.languages.findOne()
assert lang.name == 'Groovy'
// Set a new property
lang.site = 'http://groovy.codehaus.org/'
// Save the new version
db.languages.save lang

assert db.languages.findOne(name: 'Groovy').site == 'http://groovy.codehaus.org/'

// Counting the number of documents in the collection
assert db.languages.find(type: 'static').count() == 3

// Another way to count
assert db.languages.count(type: 'prototyped') == 2

// Updating a document using the '$set' operator
db.languages.update([name: 'Python'], [$set: [paradigms: ['object-oriented', 'functional', 'imperative']]])

assert 3 == db.languages.findOne(name: 'Python').paradigms.size()

// Using upsert
db.languages.update([name: 'Haskel'], [$set: [paradigms: ['functional']]], true)

assert db.languages.findOne(name: 'Haskel')

// Removing some documents
db.languages.remove(type: 'prototyped')
assert 0 == db.languages.count(type: 'prototyped')

// Removing all documents
db.languages.remove([:])
assert 0 == db.languages.count()

// To ensure complete consistency in a session use DB#inRequest
// It is analogous to user DB#requestStarted and DB#requestDone
db.inRequest {
    db.languages.insert(name: 'Objective-C')
    assert 1 == db.languages.count(name: 'Objective-C')
}

Sorting and Pagination

@Grab(group='com.gmongo', module='gmongo', version='0.9.5')
import com.gmongo.GMongo

def mongo = new GMongo()
def db = mongo.getDB("gmongo")

// Make sure that the collection is empty
db.example.drop()

// Insert 100 documents with any random value
100.times {
    db.example << [time: it, random: (Integer)(Math.random() * 100)]
}

def at = 0

// Find out how many documents are in the collection
def total = db.example.find().count()

// Sort the documents by the 'random' property ascending and Paginate over it 10 by 10
while (at < total) {
    println "At page: ${at / 10}\n"
    db.example.find().limit(10).skip(at).sort(random: 1).each {
        println "\t-- ${it}"
    }
    println "\n--------------------------"
    at += 10
}

MapReduce

@Grab(group='com.gmongo', module='gmongo', version='0.9.5')
import com.gmongo.GMongo

def mongo = new GMongo()
def db = mongo.getDB("gmongo")

def words = ['foo', 'bar', 'baz']
def rand  = new Random()		

1000.times { 
    db.words << [word: words[rand.nextInt(3)]]
}

assert db.words.count() == 1000

def result = db.words.mapReduce(
    """
    function map() {
        emit(this.word, {count: 1})
    }
    """,
    """
    function reduce(key, values) {
        var count = 0
        for (var i = 0; i < values.length; i++)
            count += values[i].count
        return {count: count}
    }
    """,
    "mrresult",
    [:] // No Query
)

assert db.mrresult.count() == 3
assert db.mrresult.find()*.value*.count.sum() == 1000

Grouping

Grouping can also be achieved. Example:

@Grab("com.gmongo:gmongo:0.9.5")
import com.gmongo.GMongo

def gmongo = new GMongo("localhost:27017")

def db = gmongo.getDB("test")

db.clicks.drop()

db.clicks.insert(day: 1, total: 10)
db.clicks.insert(day: 1, total: 14)
db.clicks.insert(day: 2, total: 45)
db.clicks.insert(day: 1, total:  9)
db.clicks.insert(day: 3, total: 32)
db.clicks.insert(day: 2, total: 11)
db.clicks.insert(day: 3, total: 34)

def result = db.clicks.group([day: true], [:], [count: 0], "function(doc, out) { out.count += doc.total }")

// Will output [[day:1.0, count:33.0], [day:2.0, count:56.0], [day:3.0, count:66.0]]
println result

And a more advanced grouping using 'keyf':

@Grab("com.gmongo:gmongo:0.9.5")
import com.gmongo.GMongo

def gmongo = new GMongo("localhost:27017")

def db = gmongo.getDB("test")

db.clicks.drop()

db.clicks.insert(day: 1, total: 10)
db.clicks.insert(day: 1, total: 14)
db.clicks.insert(day: 2, total: 45)
db.clicks.insert(day: 1, total:  9)
db.clicks.insert(day: 3, total: 32)
db.clicks.insert(day: 2, total: 11)
db.clicks.insert(day: 3, total: 34)

def keyf = "function(clicks) { return clicks.day % 2 ? { odd: true } : { even: true } }"

def command = ['$keyf': keyf, cond: [:], initial: [count: 0], $reduce: "function(doc, out) { out.count += doc.total }"]

def result = db.clicks.group(command)

// Will output [[odd:true, count:99.0], [even:true, count:56.0]]
println result  

Build

The project is build using gradle. Gradle can be found in: http://www.gradle.org

Test

To run the tests start a mongo instance on localhost:27017