* Initializes the filter by calling <code>filter.init( {@link #getFilterConfig() getFilterConfig()} );</code>.
*
* @param filter the filter to initialize with the {@code FilterConfig}.
*/
protected void initFilter(Filter filter) {
FilterConfig filterConfig = getFilterConfig();
if (filterConfig == null) {
throw new IllegalStateException("FilterConfig attribute has not been set. This must occur before filter " +
"initialization can occur.");
}
try {