Add main class

build.sbt

@@ -4,8 +4,8 @@ version := "0.1"
 
 scalaVersion := "2.11.12"
 
-mainClass in(Compile, run) := Some("com.ashessin.cs441.hw3.stocksim.RunMontecarloSimulation")
-mainClass in(Compile, packageBin) := Some("com.ashessin.cs441.hw3.stocksim.RunMontecarloSimulation")
+mainClass in(Compile, run) := Some("com.ashessin.cs441.hw3.stocksim.Start")
+mainClass in(Compile, packageBin) := Some("com.ashessin.cs441.hw3.stocksim.Start")
 
 assemblyMergeStrategy in assembly := {
   case PathList("META-INF", xs @ _*) => MergeStrategy.discard

src/main/scala/com/ashessin/cs441/hw3/stocksim/Start.scala

@@ -0,0 +1,127 @@
+package com.ashessin.cs441.hw3.stocksim
+
+import java.io.{File, IOException}
+import java.net.URISyntaxException
+import java.nio.file.{Files, Paths}
+import java.util
+import java.util.Objects
+import java.util.regex.Pattern
+
+import com.typesafe.config.{ConfigException, ConfigFactory}
+import org.apache.log4j.PropertyConfigurator.configure
+import org.slf4j.LoggerFactory
+
+/**
+ * Projects main class.
+ */
+object Start {
+  private val logger = LoggerFactory.getLogger(classOf[Start])
+
+  def main(args: Array[String]): Unit = {
+    configure(Thread.currentThread.getContextClassLoader.getResource("log4j.properties"))
+    // org.apache.log4j.Logger.getRootLogger.setLevel(org.apache.log4j.Level.DEBUG)
+    new Start(args)
+  }
+}
+
+class Start(val args: Array[String]) {
+  try if (!parseCommandLineOptions(args)) System.exit(1)
+  else System.exit(0)
+  catch {
+    case e: ConfigException.Missing =>
+      Start.logger.error("trying to load the input config file: ", e)
+    case e: ConfigException.Parse =>
+      Start.logger.error("trying to parse the input config file: ", e)
+    case e: Exception =>
+      Start.logger.error("An unexpected error happened: ", e)
+  }
+
+  @throws[Exception]
+  private def parseCommandLineOptions(args: Array[String]): Boolean = {
+    if (args.length < 1) {
+      System.out.println(showHelp)
+      return false
+    }
+    if (args(0).trim.equalsIgnoreCase("--configFile")) {
+      if (args.length == 2) {
+        val configFile = new File(args(1))
+        Start.logger.info("Trying to load config file {}", configFile.getAbsolutePath)
+        executeConfig(configFile)
+      }
+      else {
+        Start.logger.info("Executing default config")
+        val confgFile = new File(Objects.requireNonNull(
+          Thread.currentThread.getContextClassLoader.getResource("reference.conf")).toURI)
+        executeConfig(confgFile)
+      }
+      return true
+    }
+
+    val className = args(0).trim + "$"
+    val argsNew = util.Arrays.copyOfRange(args, 1, args.length)
+
+    if (className.equalsIgnoreCase("--simulate") ||
+      className == RunMontecarloSimulation.getClass.getName ||
+      className == RunMontecarloSimulation.getClass.getSimpleName) {
+      RunMontecarloSimulation.main(argsNew)
+      return true
+    }
+    false
+  }
+
+  @throws[Exception]
+  private def executeConfig(configSource: File): Unit = {
+    if (configSource == null || "" == configSource.getAbsolutePath)
+      throw new IllegalArgumentException("You must specify a file as command line parameter to --configFile.")
+    val config = ConfigFactory.load(configSource.getPath)
+    val jobs = config.getConfigList("jobs")
+    import scala.collection.JavaConversions._
+    for (job <- jobs) {
+      val arguments = new util.ArrayList[String](3)
+      arguments.add(job.getString("class"))
+      arguments.addAll(job.getStringList("args"))
+      parseCommandLineOptions(arguments.toArray(new Array[String](0)))
+    }
+  }
+
+  @throws[IOException]
+  @throws[URISyntaxException]
+  private def showHelp =
+    new String(Files.readAllBytes(Paths.get(
+      Thread.currentThread.getContextClassLoader.getResource("help.txt").toURI)))
+      .replaceAll(classOf[Start].getName, getApplicationStartCmd)
+
+  /**
+   * Gets the command used to launch the application.
+   * <p>
+   * If the application was launched from the jar file, returns a command like "java -jar name-of-the-jar-file".
+   * If it was launched directly from the class file, returns a command like "java class-file".
+   *
+   * @return
+   */
+  private def getApplicationStartCmd = {
+    val fullClassFilePath = getFullClassFilePath
+    val jarFile = regexMatch(fullClassFilePath)
+    if (jarFile.isEmpty) "java " + classOf[Start].getName
+    else "spark-submit " + jarFile
+  }
+
+  private def regexMatch(text: String): String = {
+    val matcher = Pattern.compile(".*\\/(.*\\.jar).*\\/").matcher(text)
+    if (matcher.find) return matcher.group(1)
+    ""
+  }
+
+  /**
+   * Gets the full file path of this class.
+   * This may include the path of a jar if the class is being run from a jar package.
+   *
+   * @return
+   */
+  private def getFullClassFilePath = {
+    val classFileName = '/' + classOf[Start].getName.replace('.', '/') + ".class"
+    classOf[Start].getResource(classFileName).getFile
+  }
+
+  // TODO: Improve config file parsing and cli options
+}