private RecordSessionBean recordSessionBean;
private PlaybackSessionBean playbackSessionBean;
PlaybackSessionImpl( String sessionName, File playbackFile, File recordFile,
File diffFile ) throws SessionFailedException {
super( new PlaybackSessionBean( sessionName ) );
playbackSessionBean = (PlaybackSessionBean) getSessionBean();
if ( sessionName == null || sessionName.trim().length() <= 0 ) {
error( "the session name supplied( " + sessionName +
" ) is invalid, it must be a non-null string of non-zero length" );
}