## Kotlin API

TODO== RxJava 3 API

The client provides an Rxified version of the original API. The following examples use RxJava 3.

### Simple query

    Single<RowSet<Row>> single = pool.query("SELECT * FROM users WHERE id='julien'").rxExecute();

    // Execute the query
    single.subscribe(result -> {
      System.out.println("Got " + result.size() + " rows ");
    }, err -> {
      System.out.println("Failure: " + err.getMessage());
    });

### Connection

The simplified connection API allows to easily use a connection, the `withConnection` method borrows a connection from the pool and return it for you:

    Maybe<RowSet<Row>> maybe = pool.withConnection(conn ->
      conn
        .query("INSERT INTO Users (first_name,last_name) VALUES ('Julien','Viet')")
        .rxExecute()
        .flatMap(result -> conn
          .query("SELECT * FROM Users")
          .rxExecute())
        .toMaybe());

    maybe.subscribe(rows -> {
      // Success
    }, err -> {
      // Failed
    });

### Transaction

The simplified transaction API allows to easily write transactional asynchronous flows, The `withTransaction` method start and commit a transaction for you:

    Completable completable = pool.withTransaction(conn ->
      conn
        .query("INSERT INTO Users (first_name,last_name) VALUES ('Julien','Viet')")
        .rxExecute()
        .flatMap(result -> conn
          .query("INSERT INTO Users (first_name,last_name) VALUES ('Emad','Alblueshi')")
          .rxExecute())
        .toMaybe())
      .ignoreElement();

    completable.subscribe(() -> {
      // Transaction succeeded
    }, err -> {
      // Transaction failed
    });

### Streaming

RxJava supports `Observable` and `Flowable` types, these are exposed using the `RowStream` that you can get from a `PreparedQuery`:

    Observable<Row> observable = pool.rxGetConnection().flatMapObservable(conn -> conn
      .rxBegin()
      .flatMapObservable(tx ->
        conn
          .rxPrepare("SELECT * FROM users WHERE first_name LIKE $1")
          .flatMapObservable(preparedQuery -> {
            // Fetch 50 rows at a time
            RowStream<Row> stream = preparedQuery.createStream(50, Tuple.of("julien"));
            return stream.toObservable();
          })
          .doAfterTerminate(tx::commit)));

    // Then subscribe
    observable.subscribe(row -> {
      System.out.println("User: " + row.getString("last_name"));
    }, err -> {
      System.out.println("Error: " + err.getMessage());
    }, () -> {
      System.out.println("End of stream");
    });

The same example using `Flowable`:

    Flowable<Row> flowable = pool.rxGetConnection().flatMapPublisher(conn -> conn
      .rxBegin()
      .flatMapPublisher(tx ->
        conn
          .rxPrepare("SELECT * FROM users WHERE first_name LIKE $1")
          .flatMapPublisher(preparedQuery -> {
            // Fetch 50 rows at a time
            RowStream<Row> stream = preparedQuery.createStream(50, Tuple.of("julien"));
            return stream.toFlowable();
          })
          .doAfterTerminate(tx::commit)));

    // Then subscribe
    flowable.subscribe(new Subscriber<Row>() {

      private Subscription sub;

      @Override
      public void onSubscribe(Subscription subscription) {
        sub = subscription;
        subscription.request(1);
      }

      @Override
      public void onNext(Row row) {
        sub.request(1);
        System.out.println("User: " + row.getString("last_name"));
      }

      @Override
      public void onError(Throwable err) {
        System.out.println("Error: " + err.getMessage());
      }

      @Override
      public void onComplete() {
        System.out.println("End of stream");
      }
    });