public boolean isFilterOncePerRequest() {
        return filterOncePerRequest;
    }
Returns {@code true} if the filter should only execute once per request. If set to {@code false} the filter
will execute each time it is invoked.

@return {@code true} if this filter should only execute once per request.
web/src/main/java/org/apache/shiro/web/config/ShiroFilterConfiguration.java