This is probably a very basic question, but I am stumped. I have a processing app which loads an XML file and then parses this file within the app. All is fine running locally, but I cannot get it to run as an applet. I have signed the resulting jar file, but it always fails to load the file (java.security.AccessControlException: access denied (java.io.FilePermission /data/HoCMP.xml read).

Could someone explain to me how you write code which loads a file and parses it within the app and works as an applet (the bit I am stuck on)? Is it possible? From what I have been reading on the web I am now not so sure now.

Or a webpage/article that explains it. I have been stuck on this for days now, so frustrated as my app is good to go bar this huge hurdle.

I can provide code if you want, I think this could confuse my question though?

Thanks for any help.

SmeeZee wrote on Jun 11^th, 2009, 12:19pm:

I haven't tried it yet, but I believe the applet can also read a file (resource) located in its jar file (automatically packed by Processing if it is in the data folder, from what I have read).

Note that I have read that with recent Java releases, unsigned applets can read data from other URLs, as long as these are identified as service providers (Web APIs, like Twitter or Flickr, etc.).
Not sure what it takes for this to work...

In theory, you have nothing to do: you put the file in the data dir, and use stuff like loadImage, loadFont or loadString (etc.) with just the filename. When exporting, the file should be in the jar and Processing will continue to read it from there automatically.
If it doesn't work for you, I might experiment and see if it works...

So I have been playing and found the following:

An applet which loads a text file which resides in the data directory using loadStrings() works perfectly. However if I try to load the file into object it fails to find it, example code:

public MyParser(String fileName)
{
       data = loadStrings(fileName);

       try
       {
             dbf = DocumentBuilderFactory.newInstance();
             db = dbf.newDocumentBuilder();
             myDom = db.parse(fileName);
       }
       catch (Exception e)
       {
         System.out.println("There has been an error!");  
         System.err.println(e.toString());
       }
}

So the loadStrings() works perfectly, however the db.parse(fileName) throws the error "There has been an error!
java.io.FileNotFoundException: /home/AntMan/HoCMP.xml (No such file or directory)".

In this case it is trying to load the file from my local home directory.

I believe I need the equivalent to loadStrings() but loadXML() which returns a Document rather than String[]. I have tried to find the source code for loadStrings() to see if I can code this function based on this code, but to no avail?

Can anyone advise on either the location of the code or if this function already exists?

After some research into Java applets and reading files within (see: http://www.java-tips.org/java-se-tips/java.applet/how-can-i-read-a-file-from-the-jar-file-of-an-a.html) I managed to get it working!!!

Example code showing how to do this, based on previous examples (in this example fileName contains the prefix data/):

   protected Document myDom = null;
   protected DocumentBuilderFactory dbf = null;
   protected DocumentBuilder db = null;
   protected InputStream in = null;
   protected String[] data;

   public MyParser(String fileName)
   {
       data = loadStrings(fileName);
       System.out.println("Starting this applet jar reader stuff");
       System.out.println("fileName is "+fileName);

       dbf = DocumentBuilderFactory.newInstance();
       
       try
       {
            in = getClass().getResourceAsStream(fileName);
           
            System.out.println("created input stream");    
            db = dbf.newDocumentBuilder();
            myDom = db.parse(in);    
            System.out.println("Finished loading");
       }
       catch (Exception e)
       {
            System.out.println("Problems!!!");
            System.err.println(e.toString());
       }


That was rather epic, but thankfully I have done it. Thank you for your support. I need a lie down now!