Morphia update document with undefined number of fields

Question

I'm working on a small project using morphia for MongoDB. I want to know what is the best way to update a document without knowing first hand what field to update. Say for example, I have a form, after having saved to database I might want to come back and change some fields but I haven't decided yet what to change. My current solution is doing an update for all fields whether it is changed or not and of course it throws null exception. Morphia complains on null value update. My code looks like this:

    Query<Project> q = datastore.find(Project.class, "_id", projectToUpdate.getId());

    UpdateOperations<Project> update
            = datastore.createUpdateOperations(Project.class)
                    .set("name", updatedProject.getName())
                    .set("deadline", updatedProject.getDeadline())
                    .set("priority", updatedProject.getPriority())
                    .set("completion", updatedProject.getCompletion())
                    .set("description", updatedProject.getDescription())
                    .set("projectManager", updatedProject.getPM())
                    .set("collaborators", updatedProject.getAllCollaborators())
                    .set("teams", updatedProject.getAllTeams())
                    .set("userStories", updatedProject.getUserStories())
                    .set("log", updatedProject.getLog());
    datastore.findAndModify(q, update);

---

Exception

Exception in thread "main" org.mongodb.morphia.query.QueryException: Value cannot be null.
at org.mongodb.morphia.query.UpdateOpsImpl.set(UpdateOpsImpl.java:220)
at controllers.QueryProjects.updateProject(QueryProjects.java:78)
at controllers.DBConnection.TestMongo(DBConnection.java:152)
at penelope.Main.main(Main.java:12)

I was thinking about using delegate/event handler to update each field individually but I'm afraid that might degrade the performance.

Answer 1

You should just use datastore.save(). See an example at http://mongodb.github.io/morphia/1.3/getting-started/quick-tour/