Classloading solution

Yeah, but I don't work on fridays :-)

here are two classloaders that allow code to load classes from a given directory.
the loaded classes have full premissions.
of course, the code using the class loaders should be signed.

======================= MS secure class loader ===========
import java.io.*;
import com.ms.security.*;



public class MSSecureDirectoryClassLoader extends SecurityClassLoader
{
    private File baseDir;      
    private FileInputStream fis;
   
    private PermissionSet perms;

   
   
    /**
     * Constructs a new SecuredDirectoryClassLoader with a given base directory.
     * @param baseDir - The directory of the requested class.
     */
   
    public MSSecureDirectoryClassLoader(File baseDir)
    {
        this.baseDir = baseDir;      
        PermissionDataSet pds = new PermissionDataSet();
        pds.setFullyTrusted(true);
        perms = new PermissionSet(pds);
       
      }                                                                                                                                                                               
   

    /**
     * Loads a class from the initial directory with a given class name.
     * @param name - The requested class name.
     * @param resolve - A boolean value to indicate whether to resolve this class.
     * @exception ClassNotFoundException - if class was not found.
     */
   
    protected synchronized Class loadClass(String name, boolean resolve) throws ClassNotFoundException
    {
        // First, check if the class has already been loaded
       
        Class c = findLoadedClass(name);
       
       
        if (c == null)
        {
               // the class is a system class , load it from the classpath.
              try
              {
                    c = findSystemClass(name);


              }catch (ClassNotFoundException ex){}


              //the class is not from the telmap package but was not found in the classpath. try to load it from the given directory..
              if (c ==null)
              {
                    try
                    {
                          c = readLocalClass(name);
                    }catch(Exception ex)
                    {
                          throw new  ClassNotFoundException("Class \""+name+"\" was not found at " + baseDir);
                    }
              }

        }
       
        // resolve the class.
        if (resolve)
        {
            resolveClass(c);
        }
       
       
        return c;
    }
   
   
    /**
     * Loads a class from the local drive, and defines it using security parameters.
     * @param name - The requested class name.       
     * @exception Exception - if class was not found or if defining it is not possible.
     */
    private Class readLocalClass(String name) throws Exception
    {
        try{
           
            byte[] class_data = readClass(name);                        
           
           
            return  defineClass(name,
                                class_data,
                                0,
                                class_data.length,
                                perms,
                                (java.security.Principal)null);
           
           
        }catch(Exception ex){
            throw ex;                              
        }
    }

    public InputStream getResourceAsStream(String name)
    {
        try
        {
            return new ByteArrayInputStream(readFile(new File(baseDir,name)));
        }
        catch (IOException ex)
        {
            return null;
        }
    }


   
    private byte[] readClass(String className) throws IOException
    {
        PolicyEngine.assertPermission(PermissionID.FILEIO);
        className = replaceAll(className,".",File.separator);
        return readFile(new File(baseDir,(className.endsWith(".class")) ? className : className + ".class"));
    }

    private static byte[] readFile(File file) throws IOException
    {
        byte data[] = new byte[(int)file.length()];
        DataInputStream fin = null;
        try
        {
            fin = new DataInputStream(new FileInputStream(file));
            fin.readFully(data);
            return data;
        }
        finally
        {
            if(fin != null) fin.close();
        }
    }
   
     private static String replaceAll(String where, String what, String with)
     {
            StringBuffer buf = new StringBuffer(where.length());
            int whatLength = what.length();

            int startIndex = -1;
            int lastIndex = 0;
            while((startIndex = where.indexOf(what,lastIndex))!= -1)
            {
                    buf.append(where.substring(lastIndex,startIndex)).append(with);
                    lastIndex = startIndex+whatLength;
            }
            buf.append(where.substring(lastIndex));
            return buf.toString();
     }

}
==========================================================


======================= SUN secure class loader ==========
import java.io.*;
import java.net.MalformedURLException;
import java.security.*;

class DirectoryClassLoader extends ClassLoader
{
    private ProtectionDomain pd;

    private File baseDir;

    public DirectoryClassLoader(File baseDir)
    {
        this.baseDir = baseDir;
        try
        {
            CodeSource codeSource = new CodeSource(baseDir.toURL(),null);
            Permissions permissions = new Permissions();

            permissions.add(new AllPermission());
            pd = new ProtectionDomain(codeSource,permissions);
        }
        catch (MalformedURLException ex)
        {
            ex.printStackTrace();
            return;
        }
    }


    protected Class findClass(String name) throws ClassNotFoundException
    {
        try
        {
            byte classBytes[] = readClass(name);
            Class cl = defineClass(name,classBytes,0,classBytes.length,pd);
            return cl;
        }
        catch (IOException ex)
        {
            throw new ClassNotFoundException("Unable to load class " + name + " from " + baseDir);
        }
    }

    public InputStream getResourceAsStream(String name)
    {
        try
        {
            return new ByteArrayInputStream(readFile(new File(baseDir,name)));
        }
        catch (IOException ex)
        {
            return null;
        }
    }

    private byte[] readClass(String className) throws IOException
    {
        className = Utils.replaceAll(className,".",File.separator);
        return readFile(new File(baseDir,className + ".class"));
    }

    private static byte[] readFile(File file) throws IOException
    {
        byte data[] = new byte[(int)file.length()];
        FileInputStream fin = null;
        try
        {
            fin = new FileInputStream(file);
            fin.read(data);
            return data;
        }
        finally
        {
            if(fin != null) fin.close();
        }
    }
}
==========================================================