Package play.libs

Class Scala

java.lang.Object
play.libs.Scala
public class Scala extends Object
Class that contains useful java <-> scala conversion helpers.

  • Constructor Summary

    Constructors
    Constructor
    Description
    Scala()
     

  • Method Summary

    Modifier and Type
    Method
    Description
    static <T> T[]
    asArray(Class<T> clazz, scala.collection.Seq<T> scalaList)
    Converts a Scala List to an Array.
    static <K, V> Map<K,V>
    asJava(scala.collection.Map<K,V> scalaMap)
    Converts a Scala Map to Java.
    static <T> List<T>
    asJava(scala.collection.Seq<T> scalaList)
    Converts a Scala List to Java.
    static <A, B> F.Tuple<A,B>
    asJava(scala.Tuple2<A,B> tuple)
    Converts a scala Tuple2 to a java F.Tuple.
    static <A extends B, B>
    scala.collection.immutable.Seq<B>
    asScala(Collection<A> javaCollection)
    Converts a Java Collection to a Scala Seq.
    static <A> scala.Function0<A>
    asScala(Callable<A> callable)
    Converts a Java Callable to a Scala Function0.
    static <K, V> scala.collection.immutable.Map<K,V>
    asScala(Map<K,V> javaMap)
    Converts a Java Map to Scala.
    static <A> scala.Function0<scala.concurrent.Future<A>>
    asScalaWithFuture(Callable<CompletionStage<A>> callable)
    Converts a Java Callable to a Scala Function0.
    static <C> scala.reflect.ClassTag<C>
    classTag()
     
    static <A, B> scala.collection.immutable.Map<A,B>
    emptyMap()
     
    static <T> scala.collection.Seq<T>
    emptySeq()
     
    static RuntimeException
    noMatch()
    Throw this exception to indicate that a partial function doesn't match.
    static <T> scala.Option<T>
    None()
     
    static <T> scala.Option<T>
    Option(T t)
    Wrap a value into a Scala Option.
    static <T> T
    orElse(scala.Option<T> opt, T defaultValue)
    Wraps a Scala Option, handling None by returning a defaultValue
    static <T> T
    orNull(scala.Option<T> opt)
    Wraps a Scala Option, handling None as null.
    static <A, B> scala.PartialFunction<A,B>
    partialFunction(Function<A,B> f)
    Create a Scala PartialFunction from a function.
    static <T> scala.collection.immutable.Seq<T>
    toSeq(List<T> list)
    Converts a Java List to Scala Seq.
    static <T> scala.collection.immutable.Seq<T>
    toSeq(T[] array)
    Converts a Java Array to Scala Seq.
    static <A, B> scala.Tuple2<A,B>
    Tuple(A a, B b)
    Creates a Scala Tuple2.
    static <T> scala.collection.immutable.Seq<T>
    varargs(T... array)
    Converts a Java varargs to Scala varargs.

    Methods inherited from class java.lang.Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

  • Constructor Details

    • Scala

      public Scala()

  • Method Details

    • toSeq

      public static <T> scala.collection.immutable.Seq<T> toSeq(List<T> list)
      Converts a Java List to Scala Seq.
      Type Parameters:
      T - the element type.
      Parameters:
      list - the java list.
      Returns:
      the converted Seq.

    • toSeq

      public static <T> scala.collection.immutable.Seq<T> toSeq(T[] array)
      Converts a Java Array to Scala Seq.
      Type Parameters:
      T - the element type.
      Parameters:
      array - the java array.
      Returns:
      the converted Seq.

    • varargs

      @SafeVarargs public static <T> scala.collection.immutable.Seq<T> varargs(T... array)
      Converts a Java varargs to Scala varargs.
      Type Parameters:
      T - the element type.
      Parameters:
      array - the java array.
      Returns:
      the Scala varargs

    • orNull

      public static <T> T orNull(scala.Option<T> opt)
      Wraps a Scala Option, handling None as null.
      Type Parameters:
      T - the type in the Option.
      Parameters:
      opt - the scala option.
      Returns:
      the value of the option, or null if opt.isDefined is false.

    • orElse

      public static <T> T orElse(scala.Option<T> opt, T defaultValue)
      Wraps a Scala Option, handling None by returning a defaultValue
      Type Parameters:
      T - the type in the Option.
      Parameters:
      opt - the scala option.
      defaultValue - the default value if None is found.
      Returns:
      the return value.

    • asJava

      public static <K, V> Map<K,V> asJava(scala.collection.Map<K,V> scalaMap)
      Converts a Scala Map to Java.
      Type Parameters:
      K - key type
      V - value type
      Parameters:
      scalaMap - the scala map.
      Returns:
      the java map.

    • asScala

      public static <K, V> scala.collection.immutable.Map<K,V> asScala(Map<K,V> javaMap)
      Converts a Java Map to Scala.
      Type Parameters:
      K - key type
      V - value type
      Parameters:
      javaMap - the java map
      Returns:
      the scala map.

    • asScala

      public static <A extends B, B> scala.collection.immutable.Seq<B> asScala(Collection<A> javaCollection)
      Converts a Java Collection to a Scala Seq.
      Type Parameters:
      A - the input type of Seq element
      B - the output type of Seq element
      Parameters:
      javaCollection - the java collection
      Returns:
      the scala Seq.

    • asScala

      public static <A> scala.Function0<A> asScala(Callable<A> callable)
      Converts a Java Callable to a Scala Function0.
      Type Parameters:
      A - the return type.
      Parameters:
      callable - the java callable.
      Returns:
      the scala function.

    • asScalaWithFuture

      public static <A> scala.Function0<scala.concurrent.Future<A>> asScalaWithFuture(Callable<CompletionStage<A>> callable)
      Converts a Java Callable to a Scala Function0.
      Type Parameters:
      A - the return type.
      Parameters:
      callable - the java callable.
      Returns:
      the scala function in a Scala Future.

    • asJava

      public static <T> List<T> asJava(scala.collection.Seq<T> scalaList)
      Converts a Scala List to Java.
      Type Parameters:
      T - the return type.
      Parameters:
      scalaList - the scala list.
      Returns:
      the java list

    • asArray

      public static <T> T[] asArray(Class<T> clazz, scala.collection.Seq<T> scalaList)
      Converts a Scala List to an Array.
      Type Parameters:
      T - the return type.
      Parameters:
      clazz - the element class type
      scalaList - the scala list.
      Returns:
      the array

    • Option

      public static <T> scala.Option<T> Option(T t)
      Wrap a value into a Scala Option.
      Type Parameters:
      T - the element type.
      Parameters:
      t - the java value.
      Returns:
      the converted Option.

    • None

      public static <T> scala.Option<T> None()
      Type Parameters:
      T - the type parameter
      Returns:
      a scala None.

    • Tuple

      public static <A, B> scala.Tuple2<A,B> Tuple(A a, B b)
      Creates a Scala Tuple2.
      Type Parameters:
      A - input parameter type
      B - return type.
      Parameters:
      a - element one of the tuple.
      b - element two of the tuple.
      Returns:
      an instance of Tuple2 with the elements.

    • asJava

      public static <A, B> F.Tuple<A,B> asJava(scala.Tuple2<A,B> tuple)
      Converts a scala Tuple2 to a java F.Tuple.
      Type Parameters:
      A - input parameter type
      B - return type.
      Parameters:
      tuple - the Scala Tuple.
      Returns:
      an instance of Tuple with the elements.

    • emptySeq

      public static <T> scala.collection.Seq<T> emptySeq()
      Type Parameters:
      T - the type parameter
      Returns:
      an empty Scala Seq.

    • emptyMap

      public static <A, B> scala.collection.immutable.Map<A,B> emptyMap()
      Type Parameters:
      A - input parameter type
      B - return type.
      Returns:
      an empty Scala Map.

    • classTag

      public static <C> scala.reflect.ClassTag<C> classTag()
      Type Parameters:
      C - the classtag's type.
      Returns:
      an any ClassTag typed according to the Java compiler as C.

    • partialFunction

      public static <A, B> scala.PartialFunction<A,B> partialFunction(Function<A,B> f)
      Create a Scala PartialFunction from a function.

      A PartialFunction is one that isn't defined for the whole of its domain. If the function isn't defined for a particular input parameter, it can throw F.noMatch(), and this will be translated into the semantics of a Scala PartialFunction.

      For example: 

           Flow<String, Integer, ?> collectInts = Flow.<String>collect(Scala.partialFunction( str -> {
         try {
             return Integer.parseInt(str);
         } catch (NumberFormatException e) {
             throw Scala.noMatch();
         }
     }));
      The above code will convert a flow of String into a flow of Integer, dropping any strings that can't be parsed as integers.
      Type Parameters:
      A - input parameter type
      B - return type.
      Parameters:
      f - The function to make a partial function from.
      Returns:
      a Scala PartialFunction.

    • noMatch

      public static RuntimeException noMatch()
      Throw this exception to indicate that a partial function doesn't match.
      Returns:
      An exception that indicates a partial function doesn't match.