Idiomatic try/catch in Scala

StreamPrinter.snb.ipynb

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      "source": "created with the [Spark Notebook](http://spark-notebook.io)"
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      "cell_type": "markdown",
      "source": "# Idiomatic way of handling a resource\nAnd closing resources after use, in good and bad times"
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      "cell_type": "code",
      "source": "import scala.util.Try\nimport java.io._\nimport scala.io.Source",
      "outputs": [
        {
          "name": "stdout",
          "output_type": "stream",
          "text": "import scala.util.Try\nimport java.io._\nimport scala.io.Source\n"
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          "execution_count": 46,
          "time": "Took: 362 milliseconds, at 2016-12-14 9:1"
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      "cell_type": "markdown",
      "source": "### Modified version of safeFilePrint, with added \"println\" to get hints of the execution paths"
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      "cell_type": "code",
      "source": "def safeFilePrint(tf: => OutputStream)(op: PrintWriter => Unit): Try[Unit] = {\n  val os = Try(tf) \n  val write = {\n    val writer = os.map(f => new PrintWriter(f))\n    val writeOp = writer.map{w => \n                             println(\"writing to stream\")\n                             op(w)}\n    val flush = writer.map(_.flush)\n    writeOp.flatMap(_=> flush)\n  }\n  val close = os.map{stream =>\n      println(\"closing stream\")\n      stream.close}    \n  \n  write.flatMap(_ => close)\n}",
      "outputs": [
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          "output_type": "stream",
          "text": "safeFilePrint: (tf: => java.io.OutputStream)(op: java.io.PrintWriter => Unit)scala.util.Try[Unit]\n"
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          "execution_count": 47,
          "time": "Took: 297 milliseconds, at 2016-12-14 9:1"
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      "cell_type": "markdown",
      "source": "### Happy writing"
    },
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        "id": "BC18FA01A9D0424EABB92178F625A66B"
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      "cell_type": "code",
      "source": "safeFilePrint(new FileOutputStream(new File(\"/tmp/fo-test\"))){writer => \n   (1 to 17).foreach(i => writer.print(s\"record $i\"))\n}",
      "outputs": [
        {
          "name": "stdout",
          "output_type": "stream",
          "text": "writing to stream\nclosing stream\nres87: scala.util.Try[Unit] = Success(())\n"
        },
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          "data": {
            "text/html": "Success(())"
          },
          "output_type": "execute_result",
          "execution_count": 53,
          "time": "Took: 341 milliseconds, at 2016-12-14 9:1"
        }
      ]
    },
    {
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      "cell_type": "markdown",
      "source": "Did we actually write anything?"
    },
    {
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        "id": "10C513DC928F46D9938B75EA067CD429"
      },
      "cell_type": "code",
      "source": "Source.fromFile(\"/tmp/fo-test\").getLines.mkString",
      "outputs": [
        {
          "name": "stdout",
          "output_type": "stream",
          "text": "res89: String = record 1record 2record 3record 4record 5record 6record 7record 8record 9record 10record 11record 12record 13record 14record 15record 16record 17\n"
        },
        {
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          "data": {
            "text/html": "record 1record 2record 3record 4record 5record 6record 7record 8record 9record 10record 11record 12record 13record 14record 15record 16record 17"
          },
          "output_type": "execute_result",
          "execution_count": 54,
          "time": "Took: 408 milliseconds, at 2016-12-14 9:1"
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      ]
    },
    {
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      "cell_type": "markdown",
      "source": "## Exception while writing\nNote how the file is closed even in the event of an exception while writing"
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      "cell_type": "code",
      "source": "safeFilePrint(new FileOutputStream(new File(\"/tmp/bar-test\"))){writer => \n   throw new RuntimeException(\"boem, nothing here\")\n}",
      "outputs": [
        {
          "name": "stdout",
          "output_type": "stream",
          "text": "writing to stream\nclosing stream\nres91: scala.util.Try[Unit] = Failure(java.lang.RuntimeException: boem, nothing here)\n"
        },
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          "data": {
            "text/html": "Failure(java.lang.RuntimeException: boem, nothing here)"
          },
          "output_type": "execute_result",
          "execution_count": 55,
          "time": "Took: 322 milliseconds, at 2016-12-14 9:1"
        }
      ]
    },
    {
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      "cell_type": "markdown",
      "source": "## Exception while creating the stream\nIn this case, we have no stream, so we do nothing more than return the failure"
    },
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      "cell_type": "code",
      "source": "safeFilePrint(throw new RuntimeException(\"Sorry, no streaming on this wall\")){_.write(\"pee\")}",
      "outputs": [
        {
          "name": "stdout",
          "output_type": "stream",
          "text": "res93: scala.util.Try[Unit] = Failure(java.lang.RuntimeException: Sorry, no streaming on this wall)\n"
        },
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          "data": {
            "text/html": "Failure(java.lang.RuntimeException: Sorry, no streaming on this wall)"
          },
          "output_type": "execute_result",
          "execution_count": 56,
          "time": "Took: 321 milliseconds, at 2016-12-14 9:1"
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