Creating a jar file from a Scala file

Question

I\'m new to Scala and don\'t know Java. I want to create a jar file out of a simple Scala file. So I have my HelloWorld.scala, generate a HelloWorld.jar.

Manifest.m

Answer 1

I modified the bash script adding some intelligence including auto-manifest generation.

This script assumes that the main object is named the same as the file it is in (case sensitive). Also, either the current directory name must equal to the main object name or the main object name should be provided as a command line parameter. Launch this script from the root directory of your project. Modify the variables at the top as required.

Be aware that the script will generate the bin and dist folders and will ERASE any existing contents in bin.

#!/bin/bash

SC_DIST_PATH=dist
SC_SRC_PATH=src
SC_BIN_PATH=bin
SC_INCLUDE_LIB_JAR=scala-library.jar
SC_MANIFEST_PATH=MANIFEST.MF
SC_STARTING_PATH=$(pwd)

if [[ ! $SCALA_HOME ]] ; then
    echo "ERROR: set a SCALA_HOME environment variable"
    exit 1
fi

if [[ ! -f $SCALA_HOME/lib/$SC_INCLUDE_LIB_JAR ]] ; then
    echo "ERROR: Cannot find Scala Libraries!"
    exit 1
fi

if [[ -z "$1" ]] ; then
    SC_APP=$(basename $SC_STARTING_PATH)
else
    SC_APP=$1
fi

[[ ! -d $SC_DIST_PATH ]] && mkdir $SC_DIST_PATH

if [[ ! -d $SC_BIN_PATH ]] ; then
    mkdir "$SC_BIN_PATH"
else
    rm -r "$SC_BIN_PATH"
    if [[ -d $SC_BIN_PATH ]] ; then
        echo "ERROR:  Cannot remove temp compile directory:  $SC_BIN_PATH"
        exit 1
    fi
    mkdir "$SC_BIN_PATH"
fi

if [[ ! -d $SC_SRC_PATH ]] || [[ ! -d $SC_DIST_PATH ]] || [[ ! -d $SC_BIN_PATH ]] ; then
    echo "ERROR: Directory not found!:  $SC_SRC_PATH or $SC_DIST_PATH or $SC_BIN_PATH"
    exit 1
fi

if [[ ! -f $SC_DIST_PATH/$SC_INCLUDE_LIB_JAR ]] ; then
    cp "$SCALA_HOME/lib/$SC_INCLUDE_LIB_JAR" "$SC_DIST_PATH"
fi

SCALA_MAIN=$(find ./$SC_SRC_PATH -name "$SC_APP.scala")
COMPILE_STATUS=$?
SCALA_MAIN_COUNT=$(echo "$SCALA_MAIN" | wc -l)

if [[ $SCALA_MAIN_COUNT != "1" ]] || [[ ! $COMPILE_STATUS == 0 ]] ; then
    echo "Main source file not found or too many exist!:  $SC_APP.scala"
    exit 1
fi

if [[ -f $SC_DIST_PATH/$SC_APP.jar ]] ; then
    rm "$SC_DIST_PATH/$SC_APP.jar"  
    if [[ -f $SC_DIST_PATH/$SC_APP.jar ]] ; then
        echo "Unable to remove existing distribution!:  $SC_DIST_PATH/$SC_APP.jar"
        exit 1
    fi
fi

if [[ ! -f $SC_MANIFEST_PATH ]] ; then
    LEN_BASE=$(echo $(( $(echo "./$SC_SRC_PATH" |wc -c) - 0 )))
    SC_MAIN_CLASS=$(echo $SCALA_MAIN |cut --complement -c1-$LEN_BASE)
    SC_MAIN_CLASS=${SC_MAIN_CLASS%%.*}
    SC_MAIN_CLASS=$(echo $SC_MAIN_CLASS |awk '{gsub( "/", "'"."'"); print}')

    echo $(echo "Main-Class: "$SC_MAIN_CLASS) > $SC_MANIFEST_PATH
    echo $(echo "Class-Path: "$SC_INCLUDE_LIB_JAR) >> $SC_MANIFEST_PATH
fi

scalac -sourcepath $SC_SRC_PATH -d $SC_BIN_PATH $SCALA_MAIN
COMPILE_STATUS=$?

if [[ $COMPILE_STATUS != "0" ]] ; then
    echo "Compile Failed!"
    exit 1
fi

cd "$SC_BIN_PATH"
jar -cfm ../$SC_DIST_PATH/$SC_APP.jar ../$SC_MANIFEST_PATH *
COMPILE_STATUS=$?
cd "$SC_STARTING_PATH"

if  [[ $COMPILE_STATUS != "0" ]] || [[ ! -f $SC_DIST_PATH/$SC_APP.jar ]] ; then
    echo "JAR Build Failed!"
    exit 1
fi

echo " "
echo "BUILD COMPLETE!... TO LAUNCH:  java -jar $SC_DIST_PATH/$SC_APP.jar"
echo " "