extend FileSystem to ping nfs server

bindings/java/src/net/hyperic/sigar/NfsFileSystem.java

@@ -0,0 +1,28 @@
+package net.hyperic.sigar;
+
+public class NfsFileSystem extends FileSystem {
+
+    private static native boolean ping(String hostname);
+
+    String hostname = null;
+
+    public String getHostname() {
+        if (this.hostname == null) {
+            String dev = getDevName();
+            int ix = dev.indexOf(":");
+            if (ix != -1) {
+                this.hostname = dev.substring(0, ix);
+            }
+        }
+        return this.hostname;
+    }
+
+    public boolean ping() {
+        return ping(getHostname());
+    }
+
+    public static void main(String[] args) throws Exception {
+        Sigar.load();
+        System.out.println(NfsFileSystem.ping(args[0]));
+    }
+}