Question

I have JSON object :

{ “_id” : “1”, “_class” : “com.model.Test”, “projectList” : [ {
“projectID” : “Spring”, “resourceIDList” : [ “Mark”,”David” ] },
{ “projectID” : “MongoDB”, “resourceIDList” : [ “Nosa ] }

I need to be able to remove the resourceIDList for Project “Spring” and assign a new ResourceIDList.

The ResourceIDList is just List

Whenever I try to use the following,nothing is updated at DB:

 Query query = new Query(where("_id").is("1").and("projectID").is("Spring"));    

 mongoOperations.updateMulti( query,new Update().set("ressourceIDList",  populateResources()), Test.class);

Answer 1

Replacing the resourceIDList in the embedded document matching {“projectList.projectID”:”Spring”} may be accomplished in the JavaScript shell like so:
(I like to start with the JS shell, because it is less verbose than Java and the syntax is relatively straightforward. Examples with JS can then be applied to any of the language drivers.)

> db.collection.update({_id:"1", "projectList.projectID":"Spring"}, {$set:{"projectList.$.resourceIDList":["Something", "new"]}})

The documentation on using the “$” operator to modify embedded documents may be found in the “The $ positional operator” section of the “Updating” documentation:
http://www.mongodb.org/display/DOCS/Updating#Updating-The%24positionaloperator
There is more information on embedded documents in the “Dot Notation (Reaching into Objects)” Documentation:
http://www.mongodb.org/display/DOCS/Dot+Notation+%28Reaching+into+Objects%29

The above may be done in the Java Driver like so:

Mongo m = new Mongo("localhost", 27017);
DB db = m.getDB("test");
DBCollection myColl = db.getCollection("collection");
ArrayList<String> newResourceIDList = new ArrayList<String>();
newResourceIDList.add("Something");
newResourceIDList.add("new");
BasicDBObject myQuery = new BasicDBObject("_id", "1");
myQuery.put("projectList.projectID", "Spring");
BasicDBObject myUpdate = new BasicDBObject("$set", new BasicDBObject("projectList.$.resourceIDList", newResourceIDList));
myColl.update(myQuery, myUpdate);
System.out.println(myColl.findOne().toString());

If you have multiple documents that match {“projectList.projectID” : “Spring”} you can update them at once using the multi = true option. With the Java driver it would look like this:

myColl.update(myQuery, myUpdate, false, true);

In the above, “false” represents “upsert = false”, and “true” represents “multi = true”. This is explained in the documentation on the “Update” command:
http://www.mongodb.org/display/DOCS/Updating#Updating-update%28%29

Unfortunately, I am not familiar with the Spring framework, so I am unable to tell you how to do this with the “mongoOperations” class. Hopefully, the above will improve your understanding on how embedded documents may be updated in Mongo, and you will be able to accomplish what you need to do with Spring.