Base Kernel from spencer

.gitignore

+.gradle
+build/
+!gradle-wrapper.jar
+
+out/
+.idea/
\ No newline at end of file

LICENSE

+Copyright (c) 2017 Spencer Park
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
\ No newline at end of file

build.gradle

+import org.apache.tools.ant.filters.ReplaceTokens
+
+group = 'io.github.spencerpark'
+version = '2.3.0'
+
+apply plugin: 'java'
+apply plugin: 'maven'
+apply plugin: 'maven-publish'
+apply plugin: 'signing'
+
+sourceCompatibility = 1.8
+targetCompatibility = 1.8
+
+task wrapper(type: Wrapper) {
+    gradleVersion = '4.2.1'
+}
+
+tasks.withType(JavaCompile) {
+    options.compilerArgs << '-parameters'
+    options.compilerArgs << '-Xlint:all' << '-Xlint:-rawtypes' << '-Xlint:-serial'
+}
+
+repositories {
+    mavenCentral()
+}
+
+dependencies {
+    compile group: 'org.zeromq', name: 'jeromq', version: '0.5.1'
+    compile group: 'com.google.code.gson', name: 'gson', version: '2.8.5'
+
+    testCompile group: 'junit', name: 'junit', version: '4.12'
+    testCompile group: 'org.hamcrest', name: 'hamcrest-all', version: '1.3'
+
+    testCompile group: 'com.google.jimfs', name: 'jimfs', version: '1.1'
+}
+
+processResources {
+    def tokens = [
+            'version': project.version,
+            'project': project.name
+    ]
+    inputs.properties(tokens)
+    filter ReplaceTokens, tokens: tokens
+}
+
+task javadocJar(type: Jar) {
+    classifier = 'javadoc'
+    from javadoc
+}
+
+task sourcesJar(type: Jar) {
+    classifier = 'sources'
+    from sourceSets.main.allSource
+}
+
+artifacts {
+    archives javadocJar, sourcesJar
+}
+
+signing {
+    sign configurations.archives
+}
+
+uploadArchives {
+    repositories {
+        mavenDeployer {
+            beforeDeployment { MavenDeployment deployment -> signing.signPom(deployment) }
+
+            // ossrhUsername and ossrhPassword are defined in the global gradle.properties on the
+            // machine uploading the artifacts (including the keys). If not present only `publish`
+            // should fail, not `publishToMavenLocal`. Essentially defer the failure as long as possible.
+            def ossrhUsername = project.findProperty('ossrhUsername')
+            def ossrhPassword = project.findProperty('ossrhPassword')
+
+            repository(url: "https://oss.sonatype.org/service/local/staging/deploy/maven2/") {
+                authentication(userName: ossrhUsername, password: ossrhPassword)
+            }
+
+            snapshotRepository(url: "https://oss.sonatype.org/content/repositories/snapshots/") {
+                authentication(userName: ossrhUsername, password: ossrhPassword)
+            }
+
+            pom.project {
+                name = 'Jupyter JVM Base Kernel'
+                packaging = 'jar'
+                description = 'An abstract kernel implementation for Jupyter kernels running on the Java virtual machine.'
+                url = 'https://github.com/SpencerPark/jupyter-jvm-basekernel'
+
+                scm {
+                    url = 'https://github.com/SpencerPark/jupyter-jvm-basekernel.git'
+                    connection = 'scm:git:https://github.com/SpencerPark/jupyter-jvm-basekernel.git'
+                    developerConnection = 'scm:git:git@github.com:SpencerPark/jupyter-jvm-basekernel.git'
+                }
+
+                licenses {
+                    license {
+                        name = 'MIT License'
+                        url = 'http://opensource.org/licenses/MIT'
+                        distribution = 'repo'
+                    }
+                }
+
+                developers {
+                    developer {
+                        id = 'SpencerPark'
+                        name = 'Spencer Park'
+                        email = 'spinnr95@gmail.com'
+                    }
+                }
+            }
+        }
+    }
+}
+
+publishing {
+    publications {
+        mavenJava(MavenPublication) {
+            from components.java
+        }
+    }
+}
\ No newline at end of file

example/build.gradle

+plugins {
+    id "java"
+    id "io.github.spencerpark.jupyter-kernel-installer" version "2.1.0"
+}
+
+group 'io.github.spencerpark'
+version '1.0.0-SNAPSHOT'
+
+sourceCompatibility = 1.8
+
+wrapper {
+    gradleVersion = '4.8.1'
+    distributionType = Wrapper.DistributionType.ALL
+}
+
+repositories {
+    mavenLocal()
+    mavenCentral()
+}
+
+configurations {
+    shade
+    shade.transitive = true
+    compile.extendsFrom(shade)
+}
+
+dependencies {
+    shade group: 'io.github.spencerpark', name: 'jupyter-jvm-basekernel', version: '2.2.4'
+}
+
+jar {
+    //Include all shaded dependencies in the jar
+    from configurations.shade
+            .collect { it.isDirectory() ? it : zipTree(it) }
+
+    manifest {
+        attributes('Main-class': 'io.github.spencerpark.jupyter.INashornJS')
+    }
+}
+
+jupyter {
+    kernelName = 'nashorn-js'
+    kernelDisplayName = 'NashornJS'
+    kernelLanguage = 'js'
+    kernelInterruptMode = 'message'
+    kernelParameters {
+        list('engine-arg', 'JS_ENGINE_ARGS') {
+            separator = ' '
+            description = 'A comma separated list of arguments to give to the scripting engine.'
+        }
+    }
+}
+
+zipKernel {
+    installers {
+        with 'python'
+    }
+}
\ No newline at end of file

example/gradle/wrapper/gradle-wrapper.properties

+distributionUrl=https\://services.gradle.org/distributions/gradle-4.8.1-all.zip
+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
+zipStorePath=wrapper/dists
+zipStoreBase=GRADLE_USER_HOME

example/gradlew

+#!/usr/bin/env sh
+
+##############################################################################
+##
+##  Gradle start up script for UN*X
+##
+##############################################################################
+
+# Attempt to set APP_HOME
+# Resolve links: $0 may be a link
+PRG="$0"
+# Need this for relative symlinks.
+while [ -h "$PRG" ] ; do
+    ls=`ls -ld "$PRG"`
+    link=`expr "$ls" : '.*-> \(.*\)$'`
+    if expr "$link" : '/.*' > /dev/null; then
+        PRG="$link"
+    else
+        PRG=`dirname "$PRG"`"/$link"
+    fi
+done
+SAVED="`pwd`"
+cd "`dirname \"$PRG\"`/" >/dev/null
+APP_HOME="`pwd -P`"
+cd "$SAVED" >/dev/null
+
+APP_NAME="Gradle"
+APP_BASE_NAME=`basename "$0"`
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS=""
+
+# Use the maximum available, or set MAX_FD != -1 to use that value.
+MAX_FD="maximum"
+
+warn () {
+    echo "$*"
+}
+
+die () {
+    echo
+    echo "$*"
+    echo
+    exit 1
+}
+
+# OS specific support (must be 'true' or 'false').
+cygwin=false
+msys=false
+darwin=false
+nonstop=false
+case "`uname`" in
+  CYGWIN* )
+    cygwin=true
+    ;;
+  Darwin* )
+    darwin=true
+    ;;
+  MINGW* )
+    msys=true
+    ;;
+  NONSTOP* )
+    nonstop=true
+    ;;
+esac
+
+CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
+
+# Determine the Java command to use to start the JVM.
+if [ -n "$JAVA_HOME" ] ; then
+    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+        # IBM's JDK on AIX uses strange locations for the executables
+        JAVACMD="$JAVA_HOME/jre/sh/java"
+    else
+        JAVACMD="$JAVA_HOME/bin/java"
+    fi
+    if [ ! -x "$JAVACMD" ] ; then
+        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+    fi
+else
+    JAVACMD="java"
+    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+fi
+
+# Increase the maximum file descriptors if we can.
+if [ "$cygwin" = "false" -a "$darwin" = "false" -a "$nonstop" = "false" ] ; then
+    MAX_FD_LIMIT=`ulimit -H -n`
+    if [ $? -eq 0 ] ; then
+        if [ "$MAX_FD" = "maximum" -o "$MAX_FD" = "max" ] ; then
+            MAX_FD="$MAX_FD_LIMIT"
+        fi
+        ulimit -n $MAX_FD
+        if [ $? -ne 0 ] ; then
+            warn "Could not set maximum file descriptor limit: $MAX_FD"
+        fi
+    else
+        warn "Could not query maximum file descriptor limit: $MAX_FD_LIMIT"
+    fi
+fi
+
+# For Darwin, add options to specify how the application appears in the dock
+if $darwin; then
+    GRADLE_OPTS="$GRADLE_OPTS \"-Xdock:name=$APP_NAME\" \"-Xdock:icon=$APP_HOME/media/gradle.icns\""
+fi
+
+# For Cygwin, switch paths to Windows format before running java
+if $cygwin ; then
+    APP_HOME=`cygpath --path --mixed "$APP_HOME"`
+    CLASSPATH=`cygpath --path --mixed "$CLASSPATH"`
+    JAVACMD=`cygpath --unix "$JAVACMD"`
+
+    # We build the pattern for arguments to be converted via cygpath
+    ROOTDIRSRAW=`find -L / -maxdepth 1 -mindepth 1 -type d 2>/dev/null`
+    SEP=""
+    for dir in $ROOTDIRSRAW ; do
+        ROOTDIRS="$ROOTDIRS$SEP$dir"
+        SEP="|"
+    done
+    OURCYGPATTERN="(^($ROOTDIRS))"
+    # Add a user-defined pattern to the cygpath arguments
+    if [ "$GRADLE_CYGPATTERN" != "" ] ; then
+        OURCYGPATTERN="$OURCYGPATTERN|($GRADLE_CYGPATTERN)"
+    fi
+    # Now convert the arguments - kludge to limit ourselves to /bin/sh
+    i=0
+    for arg in "$@" ; do
+        CHECK=`echo "$arg"|egrep -c "$OURCYGPATTERN" -`
+        CHECK2=`echo "$arg"|egrep -c "^-"`                                 ### Determine if an option
+
+        if [ $CHECK -ne 0 ] && [ $CHECK2 -eq 0 ] ; then                    ### Added a condition
+            eval `echo args$i`=`cygpath --path --ignore --mixed "$arg"`
+        else
+            eval `echo args$i`="\"$arg\""
+        fi
+        i=$((i+1))
+    done
+    case $i in
+        (0) set -- ;;
+        (1) set -- "$args0" ;;
+        (2) set -- "$args0" "$args1" ;;
+        (3) set -- "$args0" "$args1" "$args2" ;;
+        (4) set -- "$args0" "$args1" "$args2" "$args3" ;;
+        (5) set -- "$args0" "$args1" "$args2" "$args3" "$args4" ;;
+        (6) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" ;;
+        (7) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" ;;
+        (8) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" ;;
+        (9) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" "$args8" ;;
+    esac
+fi
+
+# Escape application args
+save () {
+    for i do printf %s\\n "$i" | sed "s/'/'\\\\''/g;1s/^/'/;\$s/\$/' \\\\/" ; done
+    echo " "
+}
+APP_ARGS=$(save "$@")
+
+# Collect all arguments for the java command, following the shell quoting and substitution rules
+eval set -- $DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS "\"-Dorg.gradle.appname=$APP_BASE_NAME\"" -classpath "\"$CLASSPATH\"" org.gradle.wrapper.GradleWrapperMain "$APP_ARGS"
+
+# by default we should be in the correct project dir, but when run from Finder on Mac, the cwd is wrong
+if [ "$(uname)" = "Darwin" ] && [ "$HOME" = "$PWD" ]; then
+  cd "$(dirname "$0")"
+fi
+
+exec "$JAVACMD" "$@"

example/gradlew.bat

+@if "%DEBUG%" == "" @echo off
+@rem ##########################################################################
+@rem
+@rem  Gradle startup script for Windows
+@rem
+@rem ##########################################################################
+
+@rem Set local scope for the variables with windows NT shell
+if "%OS%"=="Windows_NT" setlocal
+
+set DIRNAME=%~dp0
+if "%DIRNAME%" == "" set DIRNAME=.
+set APP_BASE_NAME=%~n0
+set APP_HOME=%DIRNAME%
+
+@rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+set DEFAULT_JVM_OPTS=
+
+@rem Find java.exe
+if defined JAVA_HOME goto findJavaFromJavaHome
+
+set JAVA_EXE=java.exe
+%JAVA_EXE% -version >NUL 2>&1
+if "%ERRORLEVEL%" == "0" goto init
+
+echo.
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+goto fail
+
+:findJavaFromJavaHome
+set JAVA_HOME=%JAVA_HOME:"=%
+set JAVA_EXE=%JAVA_HOME%/bin/java.exe
+
+if exist "%JAVA_EXE%" goto init
+
+echo.
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+goto fail
+
+:init
+@rem Get command-line arguments, handling Windows variants
+
+if not "%OS%" == "Windows_NT" goto win9xME_args
+
+:win9xME_args
+@rem Slurp the command line arguments.
+set CMD_LINE_ARGS=
+set _SKIP=2
+
+:win9xME_args_slurp
+if "x%~1" == "x" goto execute
+
+set CMD_LINE_ARGS=%*
+
+:execute
+@rem Setup the command line
+
+set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
+
+@rem Execute Gradle
+"%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -classpath "%CLASSPATH%" org.gradle.wrapper.GradleWrapperMain %CMD_LINE_ARGS%
+
+:end
+@rem End local scope for the variables with windows NT shell
+if "%ERRORLEVEL%"=="0" goto mainEnd
+
+:fail
+rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
+rem the _cmd.exe /c_ return code!
+if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
+exit /b 1
+
+:mainEnd
+if "%OS%"=="Windows_NT" endlocal
+
+:omega

example/settings.gradle

+rootProject.name = 'example'
\ No newline at end of file

example/src/main/java/io/github/spencerpark/jupyter/INashornJS.java

+package io.github.spencerpark.jupyter;
+
+import io.github.spencerpark.jupyter.channels.JupyterConnection;
+import io.github.spencerpark.jupyter.channels.JupyterSocket;
+import io.github.spencerpark.jupyter.kernel.KernelConnectionProperties;
+
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.util.List;
+import java.util.logging.Level;
+
+public class INashornJS {
+    public static void main(String[] args) throws Exception {
+        if (args.length < 1)
+            throw new IllegalArgumentException("Missing connection file argument");
+
+        Path connectionFile = Paths.get(args[0]);
+
+        if (!Files.isRegularFile(connectionFile))
+            throw new IllegalArgumentException("Connection file '" + connectionFile + "' isn't a file.");
+
+        String contents = new String(Files.readAllBytes(connectionFile));
+
+        JupyterSocket.JUPYTER_LOGGER.setLevel(Level.WARNING);
+
+        KernelConnectionProperties connProps = KernelConnectionProperties.parse(contents);
+        JupyterConnection connection = new JupyterConnection(connProps);
+
+        String envEngineArgs = System.getenv("JS_ENGINE_ARGS");
+        if (envEngineArgs == null)
+            envEngineArgs = "-scripting";
+
+        String[] engineArgs = envEngineArgs.split(" ");
+
+        NashornKernel kernel = new NashornKernel(engineArgs);
+        kernel.becomeHandlerForConnection(connection);
+
+        connection.connect();
+        connection.waitUntilClose();
+    }
+}

example/src/main/java/io/github/spencerpark/jupyter/NashornKernel.java

+package io.github.spencerpark.jupyter;
+
+import io.github.spencerpark.jupyter.kernel.BaseKernel;
+import io.github.spencerpark.jupyter.kernel.LanguageInfo;
+import io.github.spencerpark.jupyter.kernel.ReplacementOptions;
+import io.github.spencerpark.jupyter.kernel.display.DisplayData;
+import io.github.spencerpark.jupyter.kernel.util.CharPredicate;
+import io.github.spencerpark.jupyter.kernel.util.SimpleAutoCompleter;
+import io.github.spencerpark.jupyter.kernel.util.StringSearch;
+import jdk.nashorn.api.scripting.NashornScriptEngineFactory;
+
+import javax.script.ScriptContext;
+import javax.script.ScriptEngine;
+import java.io.InputStreamReader;
+import java.io.OutputStreamWriter;
+
+public class NashornKernel extends BaseKernel {
+    private static final NashornScriptEngineFactory NASHORN_ENGINE_FACTORY = new NashornScriptEngineFactory();
+
+    private static final SimpleAutoCompleter autoCompleter = SimpleAutoCompleter.builder()
+            .preferLong()
+            //Keywords from a great poem at https://stackoverflow.com/a/12114140
+            .withKeywords("let", "this", "long", "package", "float")
+            .withKeywords("goto", "private", "class", "if", "short")
+            .withKeywords("while", "protected", "with", "debugger", "case")
+            .withKeywords("continue", "volatile", "interface")
+            .withKeywords("instanceof", "super", "synchronized", "throw")
+            .withKeywords("extends", "final", "export", "throws")
+            .withKeywords("try", "import", "double", "enum")
+            .withKeywords("false", "boolean", "abstract", "function")
+            .withKeywords("implements", "typeof", "transient", "break")
+            .withKeywords("void", "static", "default", "do")
+            .withKeywords("switch", "int", "native", "new")
+            .withKeywords("else", "delete", "null", "public", "var")
+            .withKeywords("in", "return", "for", "const", "true", "char")
+            .withKeywords("finally", "catch", "byte")
+            .build();
+
+    private static final CharPredicate idChar = CharPredicate.builder()
+            .inRange('a', 'z')
+            .inRange('A', 'Z')
+            .match('_')
+            .build();
+
+    private final ScriptEngine engine;
+    private final LanguageInfo languageInfo;
+
+    public NashornKernel() {
+        this("-scripting");
+    }
+
+    public NashornKernel(String... args) {
+        this(NASHORN_ENGINE_FACTORY.getScriptEngine(args));
+    }
+
+    public NashornKernel(ScriptEngine engine) {
+        this.engine = engine;
+        this.languageInfo = new LanguageInfo.Builder(engine.getFactory().getLanguageName())
+                .version(engine.getFactory().getLanguageVersion())
+                .mimetype("text/javascript")
+                .fileExtension(".js")
+                .pygments("javascript")
+                .codemirror("javascript")
+                .build();
+    }
+
+    @Override
+    public LanguageInfo getLanguageInfo() {
+        return languageInfo;
+    }
+
+    @Override
+    public DisplayData eval(String expr) throws Exception {
+        ScriptContext ctx = engine.getContext();
+
+        //Redirect the streams
+        ctx.setWriter(new OutputStreamWriter(System.out));
+        ctx.setErrorWriter(new OutputStreamWriter(System.err));
+        ctx.setReader(new InputStreamReader(System.in));
+
+        //Evaluate the code
+        Object res = engine.eval(expr, ctx);
+
+        //If the evaluation returns a non-null value (the code is an expression like
+        // 'a + b') then the return value should be this result as text. Otherwise
+        //return null for nothing to be emitted for 'Out[n]'. Side effects may have
+        //still printed something
+        return res != null ? new DisplayData(res.toString()) : null;
+    }
+
+    @Override
+    public DisplayData inspect(String code, int at, boolean extraDetail) throws Exception {
+        StringSearch.Range match = StringSearch.findLongestMatchingAt(code, at, idChar);
+        String id = "";
+        Object val = null;
+        if (match != null) {
+            id = match.extractSubString(code);
+            val = this.engine.getContext().getAttribute(id);
+        }
+
+        return new DisplayData(val == null ? "No memory value for '" + id + "'" : val.toString());
+    }
+
+    @Override
+    public ReplacementOptions complete(String code, int at) throws Exception {
+        StringSearch.Range match = StringSearch.findLongestMatchingAt(code, at, idChar);
+        if (match == null)
+            return null;
+        String prefix = match.extractSubString(code);
+        return new ReplacementOptions(autoCompleter.autocomplete(prefix), match.getLow(), match.getHigh());
+    }
+}

gradle/wrapper/gradle-wrapper.properties

+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
+zipStoreBase=GRADLE_USER_HOME
+zipStorePath=wrapper/dists
+distributionUrl=https\://services.gradle.org/distributions/gradle-4.2.1-bin.zip

gradlew

+#!/usr/bin/env sh
+
+##############################################################################
+##
+##  Gradle start up script for UN*X
+##
+##############################################################################
+
+# Attempt to set APP_HOME
+# Resolve links: $0 may be a link
+PRG="$0"
+# Need this for relative symlinks.
+while [ -h "$PRG" ] ; do
+    ls=`ls -ld "$PRG"`
+    link=`expr "$ls" : '.*-> \(.*\)$'`
+    if expr "$link" : '/.*' > /dev/null; then
+        PRG="$link"
+    else
+        PRG=`dirname "$PRG"`"/$link"
+    fi
+done
+SAVED="`pwd`"
+cd "`dirname \"$PRG\"`/" >/dev/null
+APP_HOME="`pwd -P`"
+cd "$SAVED" >/dev/null
+
+APP_NAME="Gradle"
+APP_BASE_NAME=`basename "$0"`
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS=""
+
+# Use the maximum available, or set MAX_FD != -1 to use that value.
+MAX_FD="maximum"
+
+warn () {
+    echo "$*"
+}
+
+die () {
+    echo
+    echo "$*"
+    echo
+    exit 1
+}
+
+# OS specific support (must be 'true' or 'false').
+cygwin=false
+msys=false
+darwin=false
+nonstop=false
+case "`uname`" in
+  CYGWIN* )
+    cygwin=true
+    ;;
+  Darwin* )
+    darwin=true
+    ;;
+  MINGW* )
+    msys=true
+    ;;
+  NONSTOP* )
+    nonstop=true
+    ;;
+esac
+
+CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
+
+# Determine the Java command to use to start the JVM.
+if [ -n "$JAVA_HOME" ] ; then
+    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+        # IBM's JDK on AIX uses strange locations for the executables
+        JAVACMD="$JAVA_HOME/jre/sh/java"
+    else
+        JAVACMD="$JAVA_HOME/bin/java"
+    fi
+    if [ ! -x "$JAVACMD" ] ; then
+        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+    fi
+else
+    JAVACMD="java"
+    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+fi
+
+# Increase the maximum file descriptors if we can.
+if [ "$cygwin" = "false" -a "$darwin" = "false" -a "$nonstop" = "false" ] ; then
+    MAX_FD_LIMIT=`ulimit -H -n`
+    if [ $? -eq 0 ] ; then
+        if [ "$MAX_FD" = "maximum" -o "$MAX_FD" = "max" ] ; then
+            MAX_FD="$MAX_FD_LIMIT"
+        fi
+        ulimit -n $MAX_FD
+        if [ $? -ne 0 ] ; then
+            warn "Could not set maximum file descriptor limit: $MAX_FD"
+        fi
+    else
+        warn "Could not query maximum file descriptor limit: $MAX_FD_LIMIT"
+    fi
+fi
+
+# For Darwin, add options to specify how the application appears in the dock
+if $darwin; then
+    GRADLE_OPTS="$GRADLE_OPTS \"-Xdock:name=$APP_NAME\" \"-Xdock:icon=$APP_HOME/media/gradle.icns\""
+fi
+
+# For Cygwin, switch paths to Windows format before running java
+if $cygwin ; then
+    APP_HOME=`cygpath --path --mixed "$APP_HOME"`
+    CLASSPATH=`cygpath --path --mixed "$CLASSPATH"`
+    JAVACMD=`cygpath --unix "$JAVACMD"`
+
+    # We build the pattern for arguments to be converted via cygpath
+    ROOTDIRSRAW=`find -L / -maxdepth 1 -mindepth 1 -type d 2>/dev/null`
+    SEP=""
+    for dir in $ROOTDIRSRAW ; do
+        ROOTDIRS="$ROOTDIRS$SEP$dir"
+        SEP="|"
+    done
+    OURCYGPATTERN="(^($ROOTDIRS))"
+    # Add a user-defined pattern to the cygpath arguments
+    if [ "$GRADLE_CYGPATTERN" != "" ] ; then
+        OURCYGPATTERN="$OURCYGPATTERN|($GRADLE_CYGPATTERN)"
+    fi
+    # Now convert the arguments - kludge to limit ourselves to /bin/sh
+    i=0
+    for arg in "$@" ; do
+        CHECK=`echo "$arg"|egrep -c "$OURCYGPATTERN" -`
+        CHECK2=`echo "$arg"|egrep -c "^-"`                                 ### Determine if an option
+
+        if [ $CHECK -ne 0 ] && [ $CHECK2 -eq 0 ] ; then                    ### Added a condition
+            eval `echo args$i`=`cygpath --path --ignore --mixed "$arg"`
+        else
+            eval `echo args$i`="\"$arg\""
+        fi
+        i=$((i+1))
+    done
+    case $i in
+        (0) set -- ;;
+        (1) set -- "$args0" ;;
+        (2) set -- "$args0" "$args1" ;;
+        (3) set -- "$args0" "$args1" "$args2" ;;
+        (4) set -- "$args0" "$args1" "$args2" "$args3" ;;
+        (5) set -- "$args0" "$args1" "$args2" "$args3" "$args4" ;;
+        (6) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" ;;
+        (7) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" ;;
+        (8) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" ;;
+        (9) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" "$args8" ;;
+    esac
+fi
+
+# Escape application args
+save () {
+    for i do printf %s\\n "$i" | sed "s/'/'\\\\''/g;1s/^/'/;\$s/\$/' \\\\/" ; done
+    echo " "
+}
+APP_ARGS=$(save "$@")
+
+# Collect all arguments for the java command, following the shell quoting and substitution rules
+eval set -- $DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS "\"-Dorg.gradle.appname=$APP_BASE_NAME\"" -classpath "\"$CLASSPATH\"" org.gradle.wrapper.GradleWrapperMain "$APP_ARGS"
+
+# by default we should be in the correct project dir, but when run from Finder on Mac, the cwd is wrong
+if [ "$(uname)" = "Darwin" ] && [ "$HOME" = "$PWD" ]; then
+  cd "$(dirname "$0")"
+fi
+
+exec "$JAVACMD" "$@"

gradlew.bat

+@if "%DEBUG%" == "" @echo off
+@rem ##########################################################################
+@rem
+@rem  Gradle startup script for Windows
+@rem
+@rem ##########################################################################
+
+@rem Set local scope for the variables with windows NT shell
+if "%OS%"=="Windows_NT" setlocal
+
+set DIRNAME=%~dp0
+if "%DIRNAME%" == "" set DIRNAME=.
+set APP_BASE_NAME=%~n0
+set APP_HOME=%DIRNAME%
+
+@rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+set DEFAULT_JVM_OPTS=
+
+@rem Find java.exe
+if defined JAVA_HOME goto findJavaFromJavaHome
+
+set JAVA_EXE=java.exe
+%JAVA_EXE% -version >NUL 2>&1
+if "%ERRORLEVEL%" == "0" goto init
+
+echo.
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+goto fail
+
+:findJavaFromJavaHome
+set JAVA_HOME=%JAVA_HOME:"=%
+set JAVA_EXE=%JAVA_HOME%/bin/java.exe
+
+if exist "%JAVA_EXE%" goto init
+
+echo.
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+goto fail
+
+:init
+@rem Get command-line arguments, handling Windows variants
+
+if not "%OS%" == "Windows_NT" goto win9xME_args
+
+:win9xME_args
+@rem Slurp the command line arguments.
+set CMD_LINE_ARGS=
+set _SKIP=2
+
+:win9xME_args_slurp
+if "x%~1" == "x" goto execute
+
+set CMD_LINE_ARGS=%*
+
+:execute
+@rem Setup the command line
+
+set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
+
+@rem Execute Gradle
+"%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -classpath "%CLASSPATH%" org.gradle.wrapper.GradleWrapperMain %CMD_LINE_ARGS%
+
+:end
+@rem End local scope for the variables with windows NT shell
+if "%ERRORLEVEL%"=="0" goto mainEnd
+
+:fail
+rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
+rem the _cmd.exe /c_ return code!
+if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
+exit /b 1
+
+:mainEnd
+if "%OS%"=="Windows_NT" endlocal
+
+:omega

settings.gradle

+rootProject.name = 'jupyter-jvm-basekernel'

src/main/java/io/github/spencerpark/jupyter/channels/DefaultReplyEnvironment.java

+package io.github.spencerpark.jupyter.channels;
+
+import io.github.spencerpark.jupyter.messages.ContentType;
+import io.github.spencerpark.jupyter.messages.Message;
+import io.github.spencerpark.jupyter.messages.MessageContext;
+import io.github.spencerpark.jupyter.messages.MessageType;
+import io.github.spencerpark.jupyter.messages.publish.PublishStatus;
+import io.github.spencerpark.jupyter.messages.reply.ErrorReply;
+
+import java.util.Deque;
+import java.util.LinkedList;
+
+public class DefaultReplyEnvironment implements ReplyEnvironment {
+    private final JupyterSocket shell;
+    private final JupyterSocket iopub;
+
+    private final MessageContext context;
+
+    private Deque<Runnable> deferred = new LinkedList<>();
+    private boolean defer = false;
+
+    public DefaultReplyEnvironment(JupyterSocket shell, JupyterSocket iopub, MessageContext context) {
+        this.shell = shell;
+        this.iopub = iopub;
+        this.context = context;
+    }
+
+    public JupyterSocket getShell() {
+        return shell;
+    }
+
+    public JupyterSocket getIopub() {
+        return iopub;
+    }
+
+    public MessageContext getContext() {
+        return context;
+    }
+
+    @Override
+    public void publish(Message<?> msg) {
+        if (defer) {
+            deferred.push(() -> iopub.sendMessage(msg));
+            this.defer = false;
+        } else {
+            iopub.sendMessage(msg);
+        }
+    }
+
+    @Override
+    public void reply(Message<?> msg) {
+        if (defer) {
+            deferred.push(() -> shell.sendMessage(msg));
+            this.defer = false;
+        } else {
+            shell.sendMessage(msg);
+        }
+    }
+
+    @Override
+    public ReplyEnvironment defer() {
+        this.defer = true;
+        return this;
+    }
+
+    @Override
+    public void defer(Runnable action) {
+        this.deferred.push(action);
+    }
+
+    @Override
+    public void resolveDeferrals() {
+        if (this.defer)
+            throw new IllegalStateException("Reply environment is in defer mode but a resolution was request.");
+
+        while (!deferred.isEmpty())
+            deferred.pop().run();
+    }
+
+    @Override
+    public <T extends ContentType<T>> void publish(T content) {
+        publish(new Message<>(context, content.getType(), content));
+    }
+
+    @Override
+    public <T extends ContentType<T>> void reply(T content) {
+        reply(new Message<>(context, content.getType(), content));
+    }
+
+    @Override
+    @SuppressWarnings("unchecked")
+    public void replyError(MessageType<?> type, ErrorReply error) {
+        reply(new Message(context, type, error));
+    }
+
+    @Override
+    public void setStatusBusy() {
+        publish(PublishStatus.BUSY);
+    }
+
+    @Override
+    public void setStatusIdle() {
+        publish(PublishStatus.IDLE);
+    }
+
+    @Override
+    public void setBusyDeferIdle() {
+        setStatusBusy();
+        defer().setStatusIdle();
+    }
+}

src/main/java/io/github/spencerpark/jupyter/channels/HeartbeatChannel.java

+package io.github.spencerpark.jupyter.channels;
+
+import io.github.spencerpark.jupyter.kernel.KernelConnectionProperties;
+import io.github.spencerpark.jupyter.messages.HMACGenerator;
+import org.zeromq.SocketType;
+import org.zeromq.ZMQ;
+
+import java.util.concurrent.atomic.AtomicInteger;
+import java.util.logging.Level;
+import java.util.logging.Logger;
+
+public class HeartbeatChannel extends JupyterSocket {
+    private static final long HB_DEFAULT_SLEEP_MS = 500;
+
+    private static final AtomicInteger HEARTBEAT_ID = new AtomicInteger();
+
+    private final long sleep;
+    private volatile Loop pulse;
+
+    public HeartbeatChannel(ZMQ.Context context, HMACGenerator hmacGenerator, long sleep) {
+        super(context, SocketType.REP, hmacGenerator, Logger.getLogger("HeartbeatChannel"));
+        this.sleep = sleep;
+    }
+
+    public HeartbeatChannel(ZMQ.Context context, HMACGenerator hmacGenerator) {
+        this(context, hmacGenerator, HB_DEFAULT_SLEEP_MS);
+    }
+
+    private boolean isBound() {
+        return this.pulse != null;
+    }
+
+    @Override
+    public void bind(KernelConnectionProperties connProps) {
+        if (this.isBound())
+            throw new IllegalStateException("Heartbeat channel already bound");
+
+        String channelThreadName = "Heartbeat-" + HEARTBEAT_ID.getAndIncrement();
+        String addr = JupyterSocket.formatAddress(connProps.getTransport(), connProps.getIp(), connProps.getHbPort());
+
+        logger.log(Level.INFO, String.format("Binding %s to %s.", channelThreadName, addr));
+        super.bind(addr);
+
+        ZMQ.Poller poller = super.ctx.poller(1);
+        poller.register(this, ZMQ.Poller.POLLIN);
+
+        this.pulse = new Loop(channelThreadName, this.sleep, () -> {
+            int events = poller.poll(0);
+            if (events > 0) {
+                byte[] msg = this.recv();
+                if (msg == null) {
+                    //Error during receive, just continue
+                    super.logger.log(Level.SEVERE, "Poll returned 1 event but could not read the echo string");
+                    return;
+                }
+                if (!this.send(msg)) {
+                    super.logger.log(Level.SEVERE, "Could not send heartbeat reply");
+                }
+                super.logger.log(Level.FINEST, "Heartbeat pulse");
+            }
+        });
+        this.pulse.onClose(() -> {
+            logger.log(Level.INFO, channelThreadName + " shutdown.");
+            this.pulse = null;
+        });
+        this.pulse.start();
+        logger.log(Level.INFO, "Polling on " + channelThreadName);
+    }
+
+    @Override
+    public void close() {
+        if (this.isBound())
+            this.pulse.shutdown();
+
+        super.close();
+    }
+
+    @Override
+    public void waitUntilClose() {
+        if (this.pulse != null) {
+            try {
+                this.pulse.join();
+            } catch (InterruptedException ignored) { }
+        }
+    }
+}