Package play.libs

Class Scala

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

    • Constructor Summary

      Constructors 
      Constructor Description
      Scala()  

    • Method Summary

      All Methods Static Methods Concrete Methods 
      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.

    • Constructor Detail

      • Scala

        public Scala()

    • Method Detail

      • 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.