Unable to load any XML from JAR - Please help!!

Question

Hi All,
I am a student in the final days of my degree. I have been working on my final project for some time now, an applet which converts input text to a signal plot for line encoding schemes - AMI, NRZ etc. It is pretty much finished, but one small bug threatens to scuttle the entire project! I have been searching the web all day long for answers with little success, and as the castor forum still appears to be down I am posting here. Any suggestions or advice would be greatly appreciated.
The applet uses the castor databinding framework to load various XML data. I am using Eclipse 3.01 for development - when the program is run locally as an applet, everything works fine. When the program is bundled into a JAR file and nested into a clean folder with a html page and the jar file, when the command to read in XML is given, a NullPointerException occurs, indicating that castor was unable to access the XML files.
Below is one of the methods used to make castor load XML data:
     public CodeSet loadCodeXML(String _codesetFilename)
          String _mappingURI = "schema/codes/codesets-mapping.xml";
          String _codesetURI = "schema/codes/" + _codesetFilename;
                // Create a new Castor mapping object
          Mapping mapping = new Mapping();                         
        try                                                                 // Attempt to load in the selected XML character set
             mapping.loadMapping(_mappingURI);                    // Initialize 'mapping' with the map file
            Unmarshaller unmar = new Unmarshaller(mapping); // Create a new XML Unmarshaller that uses 'mapping'
            // The line below creates a new CharSet object called _codeset and populates it with the XML data
            CodeSet _codeset = (CodeSet)unmar.unmarshal(new InputSource(new FileReader(_codesetURI)));
            // The character set was successfully loaded, so pass new CharSet object back to caller and end
            return _codeset;
        } catch (Exception e) {
             // If an error occurs while extracting the XML data, this block will execute:
            JOptionPane.showMessageDialog(null, e);               // Display a message dialog containing the exception error
            return null;                                             // Do not return a CharSet object to caller
     }It would seem to me the problem lies within
          String _mappingURI = "schema/codes/codesets-mapping.xml";
          String _codesetURI = "schema/codes/" + _codesetFilename;I have read that files inside a JAR can be accessed in this way ( http://archive.codehaus.org/castor/user/msg00025.html ) but it won't appear to work.
If these are set to a full system path (outside any JAR) i.e. "/home/me/proj/schema/codes/codesets-mapping.xml", the application operates fine. Clearly this is no good however, as the XML data must reside within the JAR package. I have tried many permutations such as "jar://schema/..." , "/schema/..", "schema/..", with no success. I have read of using InputStream and getResource methods to access files within the jar but have had no success. I have checked the schema dir is being put into the JAR archive.
Could anyone suggest an appropriate way of loading XML files from within a JAR file in this context?
Thanks in advance for any replies.

Answer 1

Hi, me again..
Re: mr_doghead - the filename of the file is passed from the calling function
public CodeSet loadCodeXML(String _codesetFilename)eg loadCodeXML(ami.xml) will return a CodeSet object containing the ami xml data
Anyway, I've manged to fix it up. The problem actually lies within castor, not my code at all. This is a known bug in castor that the dev's deemed 'not important' to fix, but I have to say the work around is EXTREMLY poorly documented online. Hence, this post is just to say how to fix it up if ne1 else is having trouble...
To load mappings, use:
mapping.loadMapping(getClass().getResource(_mappingURI).toString());where _mappingURI is a string such as "/xml/mapfile.xml"
However, the unmarshalling method takes in a file object, so getResourceAsStream must be used:
CharSet _charset = (CharSet)unmar.unmarshal(new InputSource(getClass().getResourceAsStream(_charsetURI)));Where CharSet is your custom object you are marshalling into, and _charsetURI is a relative path to your xml file.
Ugly as hell? Very.
Does it work? Perfectly.
take it ez guys, time for me to go hand this sht in! ;D