- Classroom file watcher was not working as expected because lastModifiedTime of a directory is not updated when a file is changed inside it.

- Added functions watchDir/unwatchDir which is responsible for watching all files and subdirectories changes
- Callback is called once for each detected change
- Changed classroom to check for the last "refresh" made to avoid multiple refreshes without changes
- Changed refresh time to 3s because it is much more comfortable
  - I don't think this would be an issue because checking for lastModifiedTime should be very fast, perhaps even 3s is too much time
- Tested in Windows

src/main/js/modules/utils/utils.js

@@ -517,15 +517,67 @@ utils.watchFile( 'test.txt', function( file ) {
 ```
 ***/
 var filesWatched = {};
+var dirsWatched = {};
+
 exports.watchFile = function( file, callback ) {
   if ( typeof file == 'string' ) { 
     file = new File(file);
   }
+  //console.log("Watching file " + file);
   filesWatched[file.canonicalPath] = {
     callback: callback,
     lastModified: file.lastModified()
   };
 };
+
+/************************************************************************
+### utils.watchDir() function
+
+Watches for changes to the given directory and calls the function provided
+when the directory changes. It works by calling watchFile/watchDir for each
+file/subdirectory.
+
+#### Parameters
+ 
+ * Dir - the file to watch (can be a file or directory)
+ * Callback - The callback to invoke when the directory has changed. 
+              The callback takes the changed file as a parameter. 
+              For each change inside the directory the callback will also 
+              be called.
+
+#### Example
+
+```javascript
+var utils = require('utils');
+utils.watchDir( 'players/_ial', function( dir ) { 
+   console.log( dir + ' has changed');
+});
+```
+***/
+
+exports.watchDir = function( dir, callback ) {
+  if ( typeof dir == 'string' ) { 
+    dir = new File(dir);
+  }
+  //console.log("Watching dir " + dir);
+  dirsWatched[dir.canonicalPath] = {
+    callback: callback,
+    lastModified: dir.lastModified()
+  };
+  
+  var files = dir.listFiles(),file;
+  if ( !files ) {
+    return;
+  }
+  for ( var i = 0; i < files.length; i++ ) {
+    file = files[i];
+    if (file.isDirectory( )) {
+      exports.watchDir(file,callback);
+    }else{
+      exports.watchFile(file,callback);
+    }
+  }
+};
 /************************************************************************
 ### utils.unwatchFile() function
 
@@ -542,21 +594,98 @@ exports.unwatchFile = function( file, callback ) {
   if ( typeof file == 'string' ) { 
     file = new File(file);
   }
+  //console.log("Unwatching file " + file);
   delete filesWatched[file.canonicalPath];  
 };
 
-function fileWatcher() {
+/************************************************************************
+### utils.unwatchDir() function
+
+Removes a directory from the watch list and all files inside the directory
+are also "unwatched"
+
+#### Example
+```javascript
+var utils = require('utils');
+utils.unwatchDir ('players/_ial');
+```
+Would cause also 
+```javascript
+utils.unwatchFile (file);
+```
+for each file inside directory (and unwatchDir for each directory inside it)
+
+***/
+exports.unwatchDir = function( dir, callback ) {
+  if ( typeof dir == 'string' ) { 
+    dir = new File(dir);
+  }
+  //console.log("Unwatching dir " + dir);
+  delete dirsWatched[dir.canonicalPath];  
+  
+  var files = dir.listFiles(),file;
+  if ( !files ) {
+    return;
+  }
+  for ( var i = 0; i < files.length; i++ ) {
+    file = files[i];
+    if (file.isDirectory( )) {
+      exports.unwatchDir(file,callback);
+    }else{
+      exports.unwatchFile(file,callback);
+    }
+  }
+};
+
+function fileWatcher(calledCallbacks) {
   for (var file in filesWatched) {
     var fileObject = new File(file);
     var lm = fileObject.lastModified();
     if ( lm != filesWatched[file].lastModified ) {
+      //console.log("Change found in " + file);
       filesWatched[file].lastModified = lm;
       filesWatched[file].callback(fileObject);
+      if (!fileObject.exists()) {
+        //console.log("File " + file + " was removed.");
+        exports.unwatchFile(file,filesWatched[file].callback);
+      }
     }
   }
-  setTimeout( fileWatcher, 5000 );
 };
-setTimeout( fileWatcher, 5000 );
+
+
+//monitors directories for time change
+//when a change is detected watchFiles are invoked for each of the files in directory
+//and callback is called
+function dirWatcher(calledCallbacks) {
+  for (var dir in dirsWatched) {
+    var dirObject = new File(dir);
+    var lm = dirObject.lastModified();
+    var dw = dirsWatched[dir];
+    if ( lm != dirsWatched[dir].lastModified ) {
+      //console.log("Change found in " + dir);
+      dirsWatched[dir].lastModified = lm;
+      dirsWatched[dir].callback(dirObject);
+      
+      exports.unwatchDir(dir, dw.callback);
+      //causes all files to be rewatched
+      if (dirObject.exists()) {
+        exports.watchDir(dir, dw.callback);
+      } else {
+        //console.log("Directory " + dir + " was removed.");
+      }
+    }
+  }
+};
+
+//guarantees that a callback is only called once for each change 
+function monitorDirAndFiles() {
+  fileWatcher ();
+  dirWatcher ();
+  setTimeout( monitorDirAndFiles, 3000 );
+};
+
+setTimeout( monitorDirAndFiles, 3000 );
 /**************************************************************************
 ### utils.array() function
 

src/main/js/plugins/classroom/classroom.js

@@ -2,8 +2,8 @@ var utils = require('utils'),
   autoload = require('plugin').autoload,
   logger = __plugin.logger,
   foreach = utils.foreach,
-  watchFile = utils.watchFile,
+  watchDir = utils.watchDir,
-  unwatchFile = utils.unwatchFile,
+  unwatchDir = utils.unwatchDir,
   playersDir = __dirname + '/../../players/',
   serverAddress = utils.serverAddress();
 
@@ -104,9 +104,9 @@ function revokeScripting ( player ) {
   var playerName = '' + player.name;
   playerName = playerName.replace(/[^a-zA-Z0-9_\-]/g,'');
   var playerDir = new File( playersDir + playerName );
-  unwatchFile( playerDir );
+  unwatchDir( playerDir );
 }
-
+exports.classroomAutoloadTime = 0;
 function grantScripting( player ) {
   console.log('Enabling scripting for player ' + player.name);
   var playerName = '' + player.name;
@@ -117,9 +117,15 @@ function grantScripting( player ) {
   var playerContext = {};
   autoload( playerContext, playerDir, logger, { cache: false });
   global[playerName] = playerContext;
-
+  watchDir( playerDir, function( changedDir ){
-  watchFile( playerDir, function( changedDir ){
+    var currentTime = new java.util.Date().getTime();
+    //this check is here because this callback might get called multiple times for the watch interval
+    //one call for the file change and another for directory change 
+    //(this happens only in Linux because in Windows the folder lastModifiedTime is not changed)
+    if(currentTime-exports.classroomAutoloadTime>1000) {
       autoload(playerContext, playerDir, logger, { cache: false });
+    } 
+    exports.classroomAutoloadTime = currentTime;
   });
 
 /*