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  1. Java Driver
  2. JAVA-416

Using an Array to create a DBObject breaks .equals and .hashcode

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    • Type: Icon: Bug Bug
    • Resolution: Done
    • Priority: Icon: Minor - P4 Minor - P4
    • 2.12.0, 3.0.0
    • Affects Version/s: 2.6.5
    • Component/s: API
    • Labels:
      None
    • Environment:
      All Java
    • Fully Compatible

      Using a Java Array to store information in a DBObject breaks .equals and .hashcode:

      scala> val one = MongoDBObject("anarray" -> Array(MongoDBObject("one" -> "oneval"),MongoDBObject("two"->"twoval")))
one: com.mongodb.casbah.commons.Imports.DBObject = { "anarray" : [ { "one" : "oneval"} , { "two" : "twoval"}]}

scala> val two = MongoDBObject("anarray" -> Array(MongoDBObject("one" -> "oneval"),MongoDBObject("two"->"twoval")))
two: com.mongodb.casbah.commons.Imports.DBObject = { "anarray" : [ { "one" : "oneval"} , { "two" : "twoval"}]}

scala> one == two
res16: Boolean = false

      Using a List to store the equivalent object does not:

      scala> val three = MongoDBObject("anarray" -> List(MongoDBObject("one" -> "oneval"),MongoDBObject("two"->"twoval")))
three: com.mongodb.casbah.commons.Imports.DBObject = { "anarray" : [ { "one" : "oneval"} , { "two" : "twoval"}]}

scala> val four = MongoDBObject("anarray" -> List(MongoDBObject("one" -> "oneval"),MongoDBObject("two"->"twoval")))
four: com.mongodb.casbah.commons.Imports.DBObject = { "anarray" : [ { "one" : "oneval"} , { "two" : "twoval"}]}

scala> three == four
res17: Boolean = true

      Of course, the two objects are absolutely equal whether they are constructed with an Array or a List:

      scala> mongoCollection += one
res18: com.mongodb.WriteResult = N/A

scala> mongoCollection += three
res19: com.mongodb.WriteResult = N/A

scala> mongoCollection.find().foreach(println)
{ "_id" : { "$oid" : "4e3723614206a091d3e32a4c"} , "anarray" : [ { "one" : "oneval"} , { "two" : "twoval"}]}
{ "_id" : { "$oid" : "4e37236e4206a091d3e32a4d"} , "anarray" : [ { "one" : "oneval"} , { "two" : "twoval"}]}

scala> val recs = mongoCollection.find().toArray
recs: Array[com.mongodb.casbah.Imports.DBObject] = Array({ "_id" : { "$oid" : "4e3723614206a091d3e32a4c"} , "anarray" : [ { "one" : "oneval"} , { "two" : "twoval"}]}, { "_id" : { "$oid" : "4e37236e4206a091d3e32a4d"} , "anarray" : [ { "one" : "oneval"} , { "two" : "twoval"}]})

scala> recs(0).get("anarray") == recs(1).get("anarray")
res24: Boolean = true

      The fix should just be to store any collection that will end up as a BSON array internally as a java List.

            Assignee:
            jeff.yemin@mongodb.com Jeffrey Yemin
            Reporter:
            bhudgeons Brandon Hudgeons
            Votes:
            1 Vote for this issue
            Watchers:
            5 Start watching this issue

              Created:
              Updated:
              Resolved: