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From tillrohrmann <...@git.apache.org>
Subject [GitHub] flink pull request: [FLINK-2613] Print usage information for Scala...
Date Thu, 01 Oct 2015 09:08:17 GMT
Github user tillrohrmann commented on a diff in the pull request:

    https://github.com/apache/flink/pull/1106#discussion_r40892740
  
    --- Diff: flink-staging/flink-scala-shell/src/main/scala/org/apache/flink/api/scala/FlinkShell.scala
---
    @@ -0,0 +1,148 @@
    +/*
    + * Licensed to the Apache Software Foundation (ASF) under one
    + * or more contributor license agreements.  See the NOTICE file
    + * distributed with this work for additional information
    + * regarding copyright ownership.  The ASF licenses this file
    + * to you under the Apache License, Version 2.0 (the
    + * "License"); you may not use this file except in compliance
    + * with the License.  You may obtain a copy of the License at
    + *
    + *     http://www.apache.org/licenses/LICENSE-2.0
    + *
    + * Unless required by applicable law or agreed to in writing, software
    + * distributed under the License is distributed on an "AS IS" BASIS,
    + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    + * See the License for the specific language governing permissions and
    + * limitations under the License.
    + */
    +
    +package org.apache.flink.api.scala
    +
    +
    +import java.io.{StringWriter, BufferedReader}
    +
    +import scala.tools.nsc.Settings
    +
    +import org.apache.flink.configuration.Configuration
    +import org.apache.flink.runtime.minicluster.LocalFlinkMiniCluster
    +
    +import scala.tools.nsc.interpreter._
    +
    +
    +object FlinkShell {
    +
    +  val LOCAL = 0;
    +  val REMOTE = 1;
    +  val UNDEFINED = -1;
    +
    +  var bufferedReader: BufferedReader = null;
    +
    +  def main(args: Array[String]) {
    +
    +    // scopt, command line arguments
    +    case class Config(
    +        port: Int = -1,
    +        host: String = "none",
    +        externalJars: Option[Array[String]] = None,
    +        flinkShellExecutionMode : Int = UNDEFINED)
    +
    +    val parser = new scopt.OptionParser[Config]("start-scala-shell.sh") {
    +      head ("Flink Scala Shell")
    +
    +      cmd("local") action {
    +        (_,c) => c.copy( host = "none", port = -1, flinkShellExecutionMode = LOCAL)
    +      } text("starts Flink scala shell with a local Flink cluster\n") children(
    +        opt[(String)] ("addclasspath") abbr("a") valueName("<path/to/jar>") action
{
    +          case (x,c) =>
    +            val xArray = x.split(":")
    +            c.copy(externalJars = Option(xArray))
    +          } text("specifies additional jars to be used in Flink\n")
    +        )
    +
    +      cmd("remote") action { (_, c) =>
    +        c.copy(flinkShellExecutionMode = REMOTE)
    +      } text("starts Flink scala shell connecting to a remote cluster\n") children(
    +        arg[String]("<host>") action { (h, c) =>
    +          c.copy(host = h) }
    +          text("remote host name as string"),
    +        arg[Int]("<port>") action { (p, c) =>
    +          c.copy(port = p) }
    +          text("remote port as integer\n"),
    +        opt[(String)] ("addclasspath") abbr("a")  valueName("<path/to/jar>") action
{
    +          case (x,c) =>
    +            val xArray = x.split(":")
    +            c.copy(externalJars = Option(xArray))
    +          } text("specifies additional jars to be used in Flink")
    +
    +      )
    +      help("help") abbr("h") text("prints this usage text\n")
    +    }
    +
    +
    +    // parse arguments
    +    parser.parse (args, Config () ) match {
    +      case Some(config) =>
    +        startShell(config.host,
    +          config.port,
    +          config.flinkShellExecutionMode,
    +          config.externalJars)
    +
    +      case _ => println("Could not parse program arguments")
    +    }
    +  }
    +
    +
    +  def startShell(
    +      userHost : String, 
    +      userPort : Int,
    +      executionMode : Int,
    +      externalJars : Option[Array[String]] = None): Unit ={
    +    
    +    println("Starting Flink Shell:")
    +
    +    var cluster: LocalFlinkMiniCluster = null
    --- End diff --
    
    Can we make `cluster` a `val` of type `Option[LocalFlinkMiniCluster]` whose value is the
value of the `if-else` expression? That way we avoid `null` values which are evil.


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