{
 "cells": [
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "# Java9 via JShell (aka Kulla)\n",
    "\n",
    "Based on https://github.com/Bachmann1234/java9_kernel\n",
    "\n",
    "With changes, added MetaKernel and other fixes.\n",
    "\n",
    "For more help, see: https://java.net/downloads/adoptopenjdk/REPL_Tutorial.pdf"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 1,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      " int x = 1;\n",
      "|  Added variable x of type int with initial value 1\n",
      "\n",
      "\n"
     ]
    }
   ],
   "source": [
    "int x = 1;"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 2,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stderr",
     "output_type": "stream",
     "text": [
      " y\r\n",
      "|  Error:\r\n",
      "|  cannot find symbol\r\n",
      "|    symbol:   variable y\r\n",
      "|  y\r\n",
      "|  ^\r\n",
      "\r\n",
      "\n"
     ]
    }
   ],
   "source": [
    "y"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 3,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      " }\n",
      "|  Added method draw\n",
      "\n",
      "\n"
     ]
    }
   ],
   "source": [
    "void draw() {\n",
    "}"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 27,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      " int test_variable_name = 1;\n",
      "|  Added variable test_variable_name of type int with initial value 1\n",
      "\n",
      "\n"
     ]
    }
   ],
   "source": [
    "int test_variable_name = 1;"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Return values\n",
    "\n",
    "Notice that these expressions have return values (Out):"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 4,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      " x\n",
      "|  Variable x of type int has value 1\n",
      "\n",
      "\n"
     ]
    },
    {
     "data": {
      "text/plain": [
       "1"
      ]
     },
     "execution_count": 4,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "x"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 5,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      " 1\n",
      "|  Expression value is: 1\n",
      "|    assigned to temporary variable $1 of type int\n",
      "\n",
      "\n"
     ]
    },
    {
     "data": {
      "text/plain": [
       "1"
      ]
     },
     "execution_count": 5,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "1"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 6,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      " $1 + 42\n",
      "|  Expression value is: 43\n",
      "|    assigned to temporary variable $2 of type int\n",
      "\n",
      "\n"
     ]
    },
    {
     "data": {
      "text/plain": [
       "43"
      ]
     },
     "execution_count": 6,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "$1 + 42"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 7,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      " \"this is a test\"\n",
      "|  Expression value is: \"this is a test\"\n",
      "|    assigned to temporary variable $3 of type String\n",
      "\n",
      "\n"
     ]
    },
    {
     "data": {
      "text/plain": [
       "'this is a test'"
      ]
     },
     "execution_count": 7,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "\"this is a test\""
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 8,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      " list;\n",
      "|  Variable list of type List has value [1]\n",
      "\n",
      "\n"
     ]
    },
    {
     "data": {
      "text/plain": [
       "[1]"
      ]
     },
     "execution_count": 8,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "List list = new ArrayList();\n",
    "list.add(1);\n",
    "list;"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Magics\n",
    "\n",
    "Building the Java9 kernel around MetaKernel gives you access to magics and the shell.\n",
    "\n",
    "Here are some examples showing access to the shell and other magics:"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 9,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "Calysto Simulator.ipynb      evolved.py\t\t\t sim-movie.gif\r\n",
      "conx.py\t\t\t     IVisual VPython Demo.ipynb  simulation.png\r\n",
      "Dot Flowchart Example.ipynb  Java9.ipynb\t\t World.java\r\n",
      "eipd.py\t\t\t     Numeric.py\r\n",
      "\n"
     ]
    }
   ],
   "source": [
    "! ls"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 10,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "Created file '/home/dblank/public_html/Experiments/World.java'.\n"
     ]
    }
   ],
   "source": [
    "%%file World.java\n",
    "    \n",
    "System.out.println(\"World!\");"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 11,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      " System.out.println(\"World!\");\n",
      "World!\n",
      "\n",
      "\n"
     ]
    }
   ],
   "source": [
    "%include World.java"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 10,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "%load World.java"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 12,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      " System.out.println(\"World!\");\n",
      "World!\n",
      "\n",
      "\n"
     ]
    }
   ],
   "source": [
    "    \n",
    "System.out.println(\"World!\");"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 13,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "Calysto Simulator.ipynb      evolved.py\t\t\t sim-movie.gif\r\n",
      "conx.py\t\t\t     IVisual VPython Demo.ipynb  simulation.png\r\n",
      "Dot Flowchart Example.ipynb  Java9.ipynb\t\t World.java\r\n",
      "eipd.py\t\t\t     Numeric.py\r\n",
      "\n"
     ]
    }
   ],
   "source": [
    "%%shell\n",
    "\n",
    "ls"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Parallel Magics\n",
    "\n",
    "One very powerful magic is being able to run multiple kernels through a simple interface.\n",
    "\n",
    "First we start up a cluster (dashboard -> Cluster -> start)\n",
    "\n",
    "Next, we use the %parallel magic:"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 14,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "Waiting for engines...\n"
     ]
    }
   ],
   "source": [
    "%parallel javakernel JavaKernel"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Finally, we execute a Java program in parallel, getting back N results (just two in this case):"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 15,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "[42, 42]"
      ]
     },
     "execution_count": 15,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "%%px \n",
    "\n",
    "42"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Kernel Magics\n",
    "\n",
    "Also, because JavaKernel is a MetaKernel, from any other MetaKernel instance, we can run Java code:"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 16,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "<javakernel.kernel.JavaKernel object at 0x7f4940d7fcc0>"
      ]
     },
     "execution_count": 16,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "%kernel javakernel JavaKernel"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 17,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      " Math.sqrt(2);\n",
      "|  Expression value is: 1.4142135623730951\n",
      "|    assigned to temporary variable $1 of type double\n",
      "\n",
      "\n"
     ]
    },
    {
     "data": {
      "text/plain": [
       "1.4142135623730951"
      ]
     },
     "execution_count": 17,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "%kx Math.sqrt(2);"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## JShell commands"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 18,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      " /vars\n",
      "|    boolean $4 = true\n",
      "|    int x = 1\n",
      "|    List list = [1]\n",
      "|    int $1 = 1\n",
      "|    int $2 = 43\n",
      "|    String $3 = \"this is a test\"\n",
      "\n",
      "\n"
     ]
    }
   ],
   "source": [
    "/vars"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 19,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      " /methods\n",
      "|    printf (Ljava/lang/String;[Ljava/lang/Object;)V\n",
      "|    draw ()V\n",
      "\n",
      "\n"
     ]
    }
   ],
   "source": [
    "/methods"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 20,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      " /list all\n",
      "\n",
      "   1 : import java.util.*;\n",
      "   2 : import java.io.*;\n",
      "   3 : import java.math.*;\n",
      "   4 : import java.net.*;\n",
      "   5 : import java.util.concurrent.*;\n",
      "   6 : import java.util.prefs.*;\n",
      "   7 : import java.util.regex.*;\n",
      "   8 : void printf(String format, Object... args) { System.out.printf(format, args); }\n",
      "   9 : int x = 1;\n",
      "  10 : void draw() {\n",
      "       }\n",
      "  11 : x\n",
      "  12 : 1\n",
      "  13 : $1 + 42\n",
      "  14 : \"this is a test\"\n",
      "  15 : List list = new ArrayList();\n",
      "  16 : list.add(1);\n",
      "  17 : list;\n",
      "  18 : System.out.println(\"World!\");\n",
      "  19 : System.out.println(\"World!\");\n",
      "\n",
      "\n"
     ]
    }
   ],
   "source": [
    "/list all"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 21,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      " }\n",
      "|  Added class Test\n",
      "\n",
      "\n"
     ]
    }
   ],
   "source": [
    "// Comment\n",
    "class Test {\n",
    "    public static void main() {\n",
    "        System.out.println(\"Hallooo\");\n",
    "    }\n",
    "}"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 22,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      " test.main();\n",
      "Hallooo\n",
      "\n",
      "\n"
     ]
    }
   ],
   "source": [
    "Test test = new Test();\n",
    "test.main();\n"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 23,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      " /classes\n",
      "|    class Test\n",
      "\n",
      "\n"
     ]
    }
   ],
   "source": [
    "/classes"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 24,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      " /methods\n",
      "|    printf (Ljava/lang/String;[Ljava/lang/Object;)V\n",
      "|    draw ()V\n",
      "\n",
      "\n"
     ]
    }
   ],
   "source": [
    "/methods"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 25,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      " /vars\n",
      "|    boolean $4 = true\n",
      "|    Test test = Test@6956de9\n",
      "|    int x = 1\n",
      "|    List list = [1]\n",
      "|    int $1 = 1\n",
      "|    int $2 = 43\n",
      "|    String $3 = \"this is a test\"\n",
      "\n",
      "\n"
     ]
    }
   ],
   "source": [
    "/vars"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Command-line Completions\n",
    "\n",
    "Press TAB after a few letters for command-line completion:\n",
    "\n",
    "* type a few letters\n",
    "* press TAB\n",
    "* if only one choice, it completes; more options give popup list \n",
    "* pick one"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "<img src=\"images/java9-command-line-completion.png\">"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": false
   },
   "outputs": [],
   "source": [
    "// type t<TAB>\n",
    "t"
   ]
  }
 ],
 "metadata": {
  "kernelspec": {
   "display_name": "Java 9",
   "language": "java",
   "name": "java"
  },
  "language_info": {
   "file_extension": ".class",
   "mimetype": "application/java-vm",
   "name": "java"
  }
 },
 "nbformat": 4,
 "nbformat_minor": 0
}