/**
* Creates a <code>File</code> object for a file in the persistent storage area provided for the
* bundle by the framework. If the adaptor does not have file system support, this method will
* return <code>null</code>.
*
* <p>A <code>File</code> object for the base directory of the persistent storage area provided
* for the context bundle by the framework can be obtained by calling this method with the empty
* string ("") as the parameter. See {@link #getBundle()} for a definition of context bundle.
*
* <p>If the Java runtime environment supports permissions, the framework the will ensure that the
* bundle has <code>java.io.FilePermission</code> with actions "read","write","execute","delete"
* for all files (recursively) in the persistent storage area provided for the context bundle by
* the framework.
*
* @param filename A relative name to the file to be accessed.
* @return A <code>File</code> object that represents the requested file or <code>null</code> if
* the adaptor does not have file system support.
* @exception java.lang.IllegalStateException If the bundle context has stopped.
*/
public File getDataFile(String filename) {
checkValid();
return (framework.getDataFile(bundle, filename));
}