protected void renderButtonValue(ResponseWriter writer, boolean escaped, Object value, String title, String arialLabel) throws IOException {
        if (value == null) {
            //For ScreenReader
            String label = getIconOnlyButtonText(title, arialLabel);
            if (escaped) {
                writer.writeText(label, null);
            }
            else {
                writer.write(label);
            }
        }
        else {
            if (escaped) {
                writer.writeText(value, "value");
            }
            else {
                writer.write(value.toString());
            }
        }
    }
Renders a button value or label for screen readers if no value is present or icon only button.

@param writer The response writer
@param escaped is the button escaped?
@param value the value for the button
@param title the title for the button
@param arialLabel the aria label for the button
@throws IOException if any error occurs
primefaces/src/main/java/org/primefaces/renderkit/CoreRenderer.java