protected void append(LoggingEvent event) {
        if (!performChecks()) {
        	return;
        }
        String logOutput = this.layout.format(event);
        appenderUI.doLog(logOutput);

        if (layout.ignoresThrowable()) {
        	String[] lines = event.getThrowableStrRep();
			if (lines != null) {
				int len = lines.length;
				for (int i = 0; i < len; i++) {
					appenderUI.doLog(lines[i]);
					appenderUI.doLog(Layout.LINE_SEP);
				}
			}
		}
    }