add Java example

Author: scivision

.gitignore

@@ -1,4 +1,5 @@
+Filesystem.class
 code-coverage/
 test-results/
 *.asv
-docs/
+docs/

example/Filesystem.java

@@ -0,0 +1,101 @@
+// Filesystem class usable from the command line
+//
+// useful to test Java functions before / while implementing in Matlab
+//
+// usage:
+// $ javac Filesystem.java
+// $ java -cp . Filesystem
+//
+// To install Java Development Kit (JDK): https://www.scivision.dev/install-jdk/
+
+import java.util.Scanner;
+import java.io.File;
+
+
+public class Filesystem {
+    public static void main(String[] args) {
+        Scanner scanner = new Scanner(System.in);
+
+        String argument = "";
+        final String prompt = "Jfs> ";
+
+        System.out.print(prompt);
+
+        while (scanner.hasNextLine()) {
+            String input = scanner.nextLine();
+
+            String[] inputArray = input.split(" ");
+            String command = inputArray[0];
+
+            if (inputArray.length > 1) {
+                argument = inputArray[1];
+            } else {
+                argument = "";
+            }
+
+            if (command.equals("exit") || command.equals("q") || command.equals("\u0004")) {
+                break;
+            } else if (command.equals("java_version")) {
+                System.out.println(System.getProperty("java.version"));
+            } else if (command.equals("absolute")) {
+                System.out.println(absolute(argument));
+            } else if (command.equals("expanduser")) {
+                System.out.println(expanduser(argument));
+            } else if (command.equals("canonical")) {
+                System.out.println(canonical(argument));
+            } else if (command.equals("is_absolute")) {
+                System.out.println(is_absolute(argument));
+            } else if (command.equals("is_exe")) {
+                System.out.println(is_exe(argument));
+            } else if (command.equals("is_readable")) {
+                System.out.println(is_readable(argument));
+            } else if (command.equals("ram_free")) {
+                System.out.println(ram_free());
+            } else {
+                System.err.println("Command not found");
+            }
+
+            System.out.print(prompt);
+        }
+    }
+
+    public static String absolute(String path) {
+        File f = new File(path);
+        return f.getAbsolutePath();
+    }
+
+    public static String expanduser(String path) {
+        if (path.startsWith("~"))
+            return System.getProperty("user.home") + path.substring(1);
+
+        return path;
+    }
+
+    public static String canonical(String path) {
+        try {
+            File p = new File(path);
+            return p.getCanonicalPath();
+        } catch (java.io.IOException e) {
+            return path;
+        }
+    }
+
+    public static Boolean is_absolute(String path) {
+        return new File(path).isAbsolute();
+    }
+
+    public static Boolean is_exe(String path) {
+        File f = new File(path);
+        return f.isFile() && f.canExecute();
+    }
+
+    public static Boolean is_readable(String path) {
+        return new File(path).canRead();
+    }
+
+    public static Long ram_free() {
+        com.sun.management.OperatingSystemMXBean os = (com.sun.management.OperatingSystemMXBean)
+            java.lang.management.ManagementFactory.getOperatingSystemMXBean();
+        return os.getFreeMemorySize();
+    }
+}