Specify the MapReduceAction to be used when writing to a collection.

Applies the side-effecting function to the final result of this Observable and, returns a new Observable with the result of this Observable.

This method allows one to enforce that the callbacks are executed in a specified order.

Note that if one of the chained andThen callbacks throws an exception, that exception is not propagated to the subsequent andThen callbacks. Instead, the subsequent andThen callbacks are given the original value of this Observable.

The following example prints out 10:

Observable(1 to 10) andThen {
 case r => sys.error("runtime exception")
} andThen {
 case Success(x) => print(x)
 case Failure(t) => print("Failure")
}

Sets the number of documents to return per batch.

Sets the bypass document level validation flag.

Note:: This only applies when an $out stage is specified.

output with an action

Sets the collation options

Builds a new Observable by applying a partial function to all elements.

Example:

val justStrings = Observable(Iterable("this", 1, 2, "that")).collect{ case s: String => s }

Collects all the values of the Observable into a list and returns a new Observable with that list.

Example:

val listOfNumbers = Observable(1 to 100).collect()

Sets the collectionName for the output of the MapReduce

The default action is replace the collection if it exists, to change this use action.

Convert this observable so that it emits a single Unit to Observer.onNext before calling Observer.onComplete.

If the underlying observable errors then that is propagated to the Observer. This method is especially useful for chaining Observable[Void] in for comprehensions.

Sets the name of the database to output into.

output with an action

Creates a new Observable which returns the results of this Observable, if there is an error, it will then fallback to returning the results of the alternative "that" Observable.

If both Observables fail, the resulting Observable holds the throwable object of the first Observable.

Example:

val fallBackObservable = Observable(1 to 100) fallbackTo Observable(200 to 300)

Ensuring results from a Single Observer

fallbackTo can potentially emit results from either Observer. This often isn't desirable, so to ensure only a single Observable issues results combine with the collect[S]()* method eg:

val results = Observable(1 to 100).collect() fallbackTo Observable(200 to 300).collect()

Sets the query filter to apply to the query.

Filter

Creates a new Observable by filtering the value of the current Observable with a predicate.

If the current Observable fails, then the resulting Observable also fails.

Example:

val oddValues = Observable(1 to 100) filter { _ % 2 == 1 }

Sets the JavaScript function that follows the reduce method and modifies the output.

Requirements for the finalize Function

Helper to return a single observable limited to the first result.

Creates a new Observable by applying a function to each emitted result of the Observable. If the Observable calls errors then then the new Observable will also contain this exception.

As each emitted item passed to onNext returns an Observable, we tightly control the requests to the parent Observable. The requested amount is then passed to the child Observable and only when that is completed does the parent become available for requesting more data.

Example:

def f = Observable(1 to 10)
def g = Observable(100 to 100)
val h = for {
  x: Int <- f // returns Observable(1 to 10)
  y: Int <- g // returns Observable(100 to 100)
} yield x + y

is translated to:

f flatMap { (x: Int) => g map { (y: Int) => x + y } }

Creates a new Observable that contains the single result of the applied accumulator function.

The first item emitted by the Observable is passed to the supplied accumulator function alongside the initial value, then all other emitted items are passed along with the previous result of the accumulator function.

Example:

val countingObservable = Observable(1 to 100) foldLeft(0)((v, i) => v + 1)

Applies a function applied to each emitted result.

Automatically requests all results

Returns the head of the Observable in a scala.concurrent.Future.

Returns the head option of the Observable in a scala.concurrent.Future.

Sets the flag that specifies whether to convert intermediate data into BSON format between the execution of the map and reduce functions. Defaults to false.

mapReduce

Sets the limit to apply.

Limit

Creates a new Observable by applying a function to each emitted result of the Observable. If the Observable calls errors then then the new Observable will also contain this exception.

Example:

def f = Observable(1 to 10)
def g = Observable(100 to 100)
val h = for {
  x: Int <- f // returns Observable(1 to 10)
  y: Int <- g // returns Observable(100 to 100)
} yield x + y

is translated to:

f flatMap { (x: Int) => g map { (y: Int) => x + y } }

Sets the maximum execution time on the server for this operation.

Max Time

Use a specific execution context for future operations

Creates a new Observable that will handle any matching throwable that this Observable might contain. If there is no match, or if this Observable contains a valid result then the new Observable will contain the same.

Example:

mongoExceptionObservable recover { case e: MongoException => 0 } // final result: 0
mongoExceptionObservable recover { case e: NotFoundException => 0 } // result: exception

Creates a new Observable that will handle any matching throwable that this Observable might contain by assigning it a value of another Observable.

If there is no match, or if this Observable contains a valid result then the new Observable will contain the same result.

Example:

successfulObservable recoverWith { case e: ArithmeticException => observableB } // result: successfulObservable
mongoExceptionObservable recoverWith { case t: Throwable => observableB } // result: observableB

Ensuring results from a Single Observer

recoverWith can potentially emit results from either Observer. This often isn't desirable, so to ensure only a single Observable issues results combine with the collect[S]()* method eg:

val results = Observable(1 to 100)
  .collect()
  .recoverWith({ case t: Throwable => Observable(200 to 300).collect() })
  .subscribe((i: Seq[Int]) => print(results))

Sets the global variables that are accessible in the map, reduce and finalize functions.

mapReduce

Sets the sort criteria to apply to the query.

Sort

Request Observable to start streaming data.

This is a "factory method" and can be called multiple times, each time starting a new Subscription. Each Subscription will work for only a single Observer.

If the Observable rejects the subscription attempt or otherwise fails it will signal the error via Observer.onError.

Subscribes to the Observable and requests Long.MaxValue.

Uses the default or overridden onNext, onError, onComplete partial functions.

Subscribes to the Observable and requests Long.MaxValue.

Subscribes to the Observable and requests Long.MaxValue.

Subscribes to the Observable and requests Long.MaxValue.

Handles the automatic boxing of a Java Observable so it conforms to the interface.

Aggregates documents to a collection according to the specified map-reduce function with the given options, which must specify a non-inline result.

Creates a new Observable by applying the resultFunction function to each emitted result. If there is an error and onError is called the errorFunction function is applied to the failed result.

Sets whether to include the timing information in the result information.

Used by for-comprehensions.

Zips the values of this and that Observable, and creates a new Observable holding the tuple of their results.

If this Observable fails, the resulting Observable is failed with the throwable stored in this. Otherwise, if that Observable fails, the resulting Observable is failed with the throwable stored in that.

It will only emit as many items as the number of items emitted by the source Observable that emits the fewest items.

Sets if the post-processing step will prevent MongoDB from locking the database.

Valid only with the MapReduceAction.MERGE or MapReduceAction.REDUCE actions.

Output with an action

Sets if the output database is sharded

output with an action