Readme.md

Steps

Include all the code in PlayBingo class. Add test class method name in each section.

Register user

For user registration, we need a crud. The crud works if we extend CouchDbRepositorySupport<Class> abstract class (UserRepository should be used as a base).

The spring context is available in the CONTEXT variable. You can reference the repository bean by:

UserRepository userRepository = CONTEXT.getBean(UserRepository.class);

Please set the ID of the user according to your name. The rest of the fields are oprtional in this example.

If you want to query an user by id, the repository.get("userid") will be your call. It will throw a DocumentNotFoundException if the user does not exist. Similarly, if you want to update an user and you have a conflict, or you want to register the same user (the same id) again, you will get an UpdateConflictException.

Get one of the Bingo cards

Similarly to the UserRepository, we need to extend the crud that is called BingoCardRepository.

It needs the same functionality as the UserRepository. We need to implement the method

public BingoCard getOneNonAssigned();

The implementation of the function is as follows:

List<BingoCard> queryView = queryView("nonAssigned");

Since we would like to use a view on the database, we have to include the view in our code as an annotation on the repository:

@View( name="nonAssigned", map = "function(doc) { if(!doc.userid) emit( null, doc._id )}")

This will create a view, where only the documents will be returned, that does not have userid defined.

Pick one from the returned list (first, last, whatever, you have 60 :) ).

Mark that card as yours

You need to update the card that you retrieved, and set your userid for that card. You MUST not have more than 1 bingo card (I'm checking with a query just to make sure :) )

To do this, we need to add another view to the repository. That can be done like this (this is optional, since :

@Views ( value = {@View( name="nonAssigned", map = "function(doc) { if(!doc.userid) emit( null, doc._id )}"), @View( name="assignedtoUser", map = "function(doc, req) { emit( doc.userid, doc._id )}")})

Since we would like to query only the bingo cards that are belonging to us, we need to pass some extra parameters.

	public BingoCard getAssignedCard(String userid){
		List<BingoCard> queryView = db.queryView(createQuery("assignedtoUser")
		    .key(userid).includeDocs(true),type);
		if(queryView.size() == 1){
			return queryView.get(0);
		}
		return null;
	}

Explanation about feeds

On slides

Listening for Bingo Balls

For the feeds to work, we need to have the annotation in place for the filter to be registered. The following annotation must be present on the BallRepository class.

@Filters( value ={@Filter( name = "codeEveningGame", function = "function(doc, req) { if(doc.game == req.query.game) { return true; } return false; }")})

And as usual, the BallRepository has to act as crud as well.

The feed can be run with the following code, that should be added to the run() method of the BallFeed class:

ChangesFeed feed = db.changesFeed(command);
		try{
			while(feed.isAlive()) {
				try {
					DocumentChange documentChange = feed.next(10, TimeUnit.SECONDS);
					if(documentChange != null) {
						String doc = documentChange.getDoc();
						Ball ball = objectMapper.readValue(doc, Ball.class);
						System.out.println(ball.getNumber());
					}
				} catch (InterruptedException e) {
					System.out.println("feed killed");
				}
			}
		} catch (Exception e){
			feed.cancel();
		}

This will implement the feed, and the balls will be printed on the screen.

However, we need 1 more thing before the feed can actually start, that is to specify the command for the feed. There is a createFeedCommand() function, that should have the following code:

ChangesCommand.Builder builder = new ChangesCommand.Builder();
		builder=builder.includeDocs(true).since(0).filter("Ball/codeEveningGame").param("game", "bingo");
		return builder.build();