Play Framework/Scala example source code file (Scala.java)

This example Play Framework source code file (Scala.java) is included in my "Source Code Warehouse" project. The intent of this project is to help you more easily find Play Framework (and Scala) source code examples by using tags.

All credit for the original source code belongs to Play Framework; I'm just trying to make examples easier to find. (For my Scala work, see my Scala examples and tutorials.)

Play Framework tags/keywords

a,b, b, k,v, lib, library, none, object, option, play, play framework, scala, suppresswarnings, t, tuple

The Scala.java Play Framework example source code

/*
 * Copyright (C) 2009-2013 Typesafe Inc. <http://www.typesafe.com>
 */
package play.libs;

import java.util.*;

/**
 * Class that contains useful java <-> scala conversion helpers.
 */
public class Scala {

    /**
     * Wrap a Scala Option, handling None as null.
     */
    public static <T> T orNull(scala.Option<T> opt) {
        if(opt.isDefined()) {
            return opt.get();
        }
        return null;
    }

    /**
     * Wrap a Scala Option, handling None by returning a defaultValue
     */
    public static <T> T orElse(scala.Option<T> opt, T defaultValue) {
        if(opt.isDefined()) {
            return opt.get();
        }
        return defaultValue;
    }

    /**
     * Converts a Scala Map to Java.
     */
    public static <K,V> java.util.Map<K,V> asJava(scala.collection.Map<K,V> scalaMap) {
        return scala.collection.JavaConverters.mapAsJavaMapConverter(scalaMap).asJava();
    }

    /**
     * Converts a Java Map to Scala.
     */
    public static <A,B> scala.collection.immutable.Map<A,B> asScala(Map<A,B> javaMap) {
        return play.utils.Conversions.newMap(
                scala.collection.JavaConverters.mapAsScalaMapConverter(javaMap).asScala().toSeq()
                );
    } 

    /**
     * Converts a Scala List to Java.
     */
    public static <T> java.util.List<T> asJava(scala.collection.Seq<T> scalaList) {
        return scala.collection.JavaConverters.seqAsJavaListConverter(scalaList).asJava();
    }

    /**
     * Converts a Java List to Scala Seq.
     */
    public static <T> scala.collection.Seq<T> toSeq(java.util.List<T> list) {
        return scala.collection.JavaConverters.asScalaBufferConverter(list).asScala().toList();
    }

    /**
     * Converts a Java Array to Scala Seq.
     */
    public static <T> scala.collection.Seq<T> toSeq(T[] array) {
        return toSeq(java.util.Arrays.asList(array));
    }

    /**
     * Converts a Java varargs to Scala Seq.
     */
    public static <T> scala.collection.Seq<T> varargs(T... array) {
        return toSeq(java.util.Arrays.asList(array));
    }

    /**
     * Wrap a value into a Scala Option.
     */ 
    public static <T> scala.Option<T> Option(T t) {
        return scala.Option.apply(t);
    }

    /**
     * None
     */ 
    public static <T> scala.Option<T> None() {
        return scala.Option.apply(null);
    }

    /**
     * Create a Scala Tuple2.
     */
    @SuppressWarnings("unchecked")
    public static <A,B> scala.Tuple2<A,B> Tuple(A a, B b) {
        return new scala.Tuple2<A, B>(a, b);
    }

    /** 
     * Creates an empty Scala Seq.
     */ 
    @SuppressWarnings("unchecked")
    public static <T> scala.collection.Seq<T> emptySeq() {
        return (scala.collection.Seq<T>)toSeq(new Object[] {});
    }

    /** 
     * Creates an empty Scala Map.
     */
    public static <A,B> scala.collection.immutable.Map<A,B> emptyMap() {
        return new scala.collection.immutable.HashMap<A,B>();
    }

}