Manually pulling the systems shell magic

SpencerPark#78

docs/magics.md

@@ -124,4 +124,14 @@ The cell magic is designed to make it very simple to copy and paste from any REA
       <artifactId>jupyter-jvm-basekernel</artifactId>
       <version>2.0.0-SNAPSHOT</version>
     </dependency>
-    ```
+    ```
+
+### exec
+
+Allow user to execute system program in jupyter notebook.
+
+###### Line magic
+
+*   **aliases**: `system`
+*   **arguments**:
+    *   _varargs_ list of external program and its command line arguments to be executed

src/main/java/io/github/spencerpark/ijava/JavaKernel.java

@@ -25,6 +25,7 @@
 
 import io.github.spencerpark.ijava.execution.*;
 import io.github.spencerpark.ijava.magics.ClasspathMagics;
+import io.github.spencerpark.ijava.magics.ExecMagics;
 import io.github.spencerpark.ijava.magics.MavenResolver;
 import io.github.spencerpark.jupyter.kernel.BaseKernel;
 import io.github.spencerpark.jupyter.kernel.LanguageInfo;
@@ -95,6 +96,7 @@ public JavaKernel() {
         this.magics.registerMagics(this.mavenResolver);
         this.magics.registerMagics(new ClasspathMagics(this::addToClasspath));
         this.magics.registerMagics(new Load(List.of(".jsh", ".jshell", ".java", ".ijava"), this::eval));
+        this.magics.registerMagics(new ExecMagics());
 
         this.languageInfo = new LanguageInfo.Builder("Java")
                 .version(Runtime.version().toString())

src/main/java/io/github/spencerpark/ijava/magics/ExecMagics.java

@@ -0,0 +1,47 @@
+/*
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2018 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.
+ */
+package io.github.spencerpark.ijava.magics;
+
+import io.github.spencerpark.jupyter.kernel.magic.registry.LineMagic;
+
+import java.nio.charset.StandardCharsets;
+import java.util.List;
+import java.util.Scanner;
+
+public class ExecMagics {
+
+    @LineMagic(aliases = "system")
+    public void exec(List<String> args) throws Exception {
+        ProcessBuilder pb = new ProcessBuilder();
+        pb.command(args);
+        pb.redirectErrorStream(true);
+        Process process = pb.start();
+
+        try (Scanner scanner = new Scanner(process.getInputStream(), StandardCharsets.UTF_8)) {
+            while (scanner.hasNext()) {
+                System.out.println(scanner.nextLine());
+            }
+        }
+    }
+}