ScalaObservable

implicit class ScalaObservable[T] extends AnyRef

Extends the Java Observable and adds helpers to make Observables composable and simple to Subscribe to.

T: the type of result the Observable emits

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ScalaObservable
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Instance Constructors

new ScalaObservable(obs: => Observable[T])
obs
the original Observable

Value Members

final def !=(arg0: Any): Boolean
Definition Classes
AnyRef → Any
final def ##(): Int
Definition Classes
AnyRef → Any
final def ==(arg0: Any): Boolean
Definition Classes
AnyRef → Any
def andThen[U](pf: PartialFunction[Try[T], U]): Observable[T]
Applies the side-effecting function to the final result of this Observable and, returns a new Observable with the result of this Observable.
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")
}
```
U
the result type of the
pf
the partial function to pattern match against
returns
an
final def asInstanceOf[T0]: T0
Definition Classes
Any
def clone(): AnyRef
Attributes
protected[lang]
Definition Classes
AnyRef
Annotations
@throws(classOf[java.lang.CloneNotSupportedException]) @native()
def collect[S](): SingleObservable[Seq[T]]
Collects all the values of the Observable into a list and returns a new Observable with that list.
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()
```
returns
an Observable that emits a single item, the result of accumulator.
Note
If the Observable is large then this will consume lots of memory! If the underlying Observable is infinite this Observable will never complete.
See also
Uses foldLeft underneath
final def eq(arg0: AnyRef): Boolean
Definition Classes
AnyRef
def equals(arg0: AnyRef): Boolean
Definition Classes
AnyRef → Any
def fallbackTo[U >: T](that: Observable[U]): Observable[U]
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.
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 method eg:
```
val results = Observable(1 to 100).collect() fallbackTo Observable(200 to 300).collect()
```
U
the type of the returned Observable
that
the Observable to fallback to if this Observable fails
returns
an Observable that will fallback to the that Observable should this Observable complete with an onError.
def filter(predicate: (T) => Boolean): Observable[T]
Creates a new Observable by filtering the value of the current Observable with a predicate.
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 }
```
predicate
the function that is applied to each result emitted if it matches that result is passes to the returned Observable
returns
an Observable only containing items matching that match the predicate
def finalize(): Unit
Attributes
protected[lang]
Definition Classes
AnyRef
Annotations
@throws(classOf[java.lang.Throwable])
def flatMap[S](mapFunction: (T) => Observable[S]): Observable[S]
Creates a new Observable by applying a function to each emitted result of the Observable.
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 } }
```
S
the resulting type of each item in the Observable
mapFunction
function that transforms a each result of the receiver into an Observable and passes each result of that Observable to the returned Observable.
returns
an Observable with transformed results and / or error.
def foldLeft[S](initialValue: S)(accumulator: (S, T) => S): SingleObservable[S]
Creates a new Observable that contains the single result of the applied accumulator function.
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)
```
initialValue
the initial (seed) accumulator value
accumulator
an accumulator function to be invoked on each item emitted by the source Observable, the result of which will be used in the next accumulator call.
returns
an Observable that emits a single item, the result of accumulator.
Note
If this function is used to collect results into a collection then it could use lots of memory! If the underlying Observable is infinite this Observable will never complete.
def foreach[U](doOnEach: (T) => U): Unit
Applies a function applied to each emitted result.
Applies a function applied to each emitted result.
Automatically requests all results
U
the resulting type after the transformation
doOnEach
the anonymous function applied to each emitted item
final def getClass(): Class[_ <: AnyRef]
Definition Classes
AnyRef → Any
Annotations
@native()
def hashCode(): Int
Definition Classes
AnyRef → Any
Annotations
@native()
def head(): Future[T]
Returns the head of the Observable in a scala.concurrent.Future.
Returns the head of the Observable in a scala.concurrent.Future.
returns
the head result of the Observable.
def headOption(): Future[Option[T]]
Returns the head option of the Observable in a scala.concurrent.Future.
Returns the head option of the Observable in a scala.concurrent.Future.
returns
the head option result of the Observable.
Since
2.2
final def isInstanceOf[T0]: Boolean
Definition Classes
Any
def map[S](mapFunction: (T) => S): Observable[S]
Creates a new Observable by applying a function to each emitted result of the Observable.
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 } }
```
S
the resulting type of each item in the Observable
mapFunction
function that transforms a each result of the receiver and passes the result to the returned Observable
returns
an Observable with transformed results and / or error.
final def ne(arg0: AnyRef): Boolean
Definition Classes
AnyRef
final def notify(): Unit
Definition Classes
AnyRef
Annotations
@native()
final def notifyAll(): Unit
Definition Classes
AnyRef
Annotations
@native()
val observable: Observable[T]
def observeOn(context: ExecutionContext): Observable[T]
Use a specific execution context for future operations
Use a specific execution context for future operations
context
the execution context
returns
an Observable that uses the specified execution context
def recover[U >: T](pf: PartialFunction[Throwable, U]): Observable[U]
Creates a new Observable that will handle any matching throwable that this Observable might contain.
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
```
U
the type of the returned Observable
pf
the partial function used to pattern match against the onError throwable
returns
an Observable that will handle any matching throwable and not error.
def recoverWith[U >: T](pf: PartialFunction[Throwable, Observable[U]]): Observable[U]
Creates a new Observable that will handle any matching throwable that this Observable might contain by assigning it a value of another Observable.
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 method eg:
```
val results = Observable(1 to 100)
  .collect()
  .recoverWith({ case t: Throwable => Observable(200 to 300).collect() })
  .subscribe((i: Seq[Int]) => print(results))
```
U
the type of the returned Observable
pf
the partial function used to pattern match against the onError throwable
returns
an Observable that will handle any matching throwable and not error but recover with a new observable
def subscribe(doOnNext: (T) => Any, doOnError: (Throwable) => Any, doOnComplete: () => Any): Unit
Subscribes to the Observable and requests Long.MaxValue.
Subscribes to the Observable and requests Long.MaxValue.
Uses the default or overridden onNext, onError, onComplete partial functions.
doOnNext
anonymous function to apply to each emitted element.
doOnError
anonymous function to apply if there is an error.
doOnComplete
anonymous function to apply on completion.
def subscribe(doOnError: (Throwable) => Any, doOnComplete: () => Any): Unit
Subscribes to the Observable and requests Long.MaxValue.
Subscribes to the Observable and requests Long.MaxValue.
doOnError
anonymous function to apply if there is an error.
doOnComplete
anonymous function to apply on completion.
def subscribe(doOnNext: (T) => Any, doOnError: (Throwable) => Any): Unit
Subscribes to the Observable and requests Long.MaxValue.
Subscribes to the Observable and requests Long.MaxValue.
doOnNext
anonymous function to apply to each emitted element.
doOnError
anonymous function to apply if there is an error.
def subscribe(doOnNext: (T) => Any): Unit
Subscribes to the Observable and requests Long.MaxValue.
Subscribes to the Observable and requests Long.MaxValue.
doOnNext
anonymous function to apply to each emitted element.
final def synchronized[T0](arg0: => T0): T0
Definition Classes
AnyRef
def toFuture(): Future[Seq[T]]
Collects the Observable results and converts to a scala.concurrent.Future.
Collects the Observable results and converts to a scala.concurrent.Future.
Automatically subscribes to the Observable and uses the collect method to aggregate the results.
returns
a future representation of the whole Observable
Note
If the Observable is large then this will consume lots of memory! If the underlying Observable is infinite this Observable will never complete.
def toString(): String
Definition Classes
AnyRef → Any
def transform[S](mapFunction: (T) => S, errorMapFunction: (Throwable) => Throwable): Observable[S]
Creates a new Observable by applying the resultFunction function to each emitted 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.
S
the resulting type of each item in the Observable
mapFunction
function that transforms a each result of the receiver and passes the result to the returned Observable
errorMapFunction
function that transforms a failure of the receiver into a failure of the returned observer
returns
an Observable with transformed results and / or error.
final def wait(): Unit
Definition Classes
AnyRef
Annotations
@throws(classOf[java.lang.InterruptedException])
final def wait(arg0: Long, arg1: Int): Unit
Definition Classes
AnyRef
Annotations
@throws(classOf[java.lang.InterruptedException])
final def wait(arg0: Long): Unit
Definition Classes
AnyRef
Annotations
@throws(classOf[java.lang.InterruptedException]) @native()
final def withFilter(p: (T) => Boolean): Observable[T]
Used by for-comprehensions.
def zip[U](that: Observable[U]): Observable[(T, U)]
Zips the values of this and that Observable, and creates a new Observable holding the tuple of their results.
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.
U
the type of the that Observable
that
the Observable to zip with
returns
a new zipped Observable

Packages

Driver structure

ScalaObservable

implicit class ScalaObservable[T] extends AnyRef

Instance Constructors

Value Members

Ensuring results from a Single Observer

Ensuring results from a Single Observer

Inherited from AnyRef

Inherited from Any

Ungrouped

Packages

Driver structure

ScalaObservable

implicit class ScalaObservable[T] extends AnyRef

Instance Constructors

Value Members

Ensuring results from a Single Observer

Ensuring results from a Single Observer

Inherited from AnyRef

Inherited from Any

Ungrouped

ScalaObservable