how to pass different values to a variable in a scala object

Question

I want to create different collection in mongodb for that i have a scala object class here is my code

object Factory {

val connectionMongo = MongoConnection(SERVER)
val collectionMongo = connectionMongo(DATABASE)("collectionA")

}

i want to add different collection names for that i am doing it like this object class here is my code

    object Factory {

    var COLLECTIONName:String=""
    def setCollectionName(name:String)
    {
      COLLECTIONName=name
    }
    val connectionMongo = MongoConnection(SERVER)
    val collectionMongo = connectionMongo(DATABASE)(COLLECTIONName)

    }

class testA {

//getting collection object 
Factory.setCollectionName("collectionA")
collectionMongo.find()//fetching the record of collectionA

}

class testB {

//getting collection object 
Factory.setCollectionName("collectionB")
collectionMongo.find()//fetching the record of collectionB
}

but this code is not working as desired it always gets COLLECTIONName value to empty string "" please guide me where i am doing wrong ,please help

Answer 1

This is a typical factory pattern, you can change your collectionMongo from a val into a function like this

object Factory {
    val SERVER = "<some server>"
    val DATABASE = "<some database>"
    val connectionMongo = MongoConnection(SERVER)(DATABASE)
    def getCollection(name: String) = connectionMongo(name)
}

Usage

class testA {
    val collectionA = Factory.getCollection(nameA)
}

class testB {
    val collectionB = Factory.getCollection(nameB)
}