public TargetClassifier build(Path basePath, ObjectMapper yaml, JsonNode parameters) throws JsonProcessingException {
            RegexClassifierConfig params = yaml.treeToValue(parameters, RegexClassifierConfig.class);
            if (params.url.regexes.isEmpty() && 
                params.title.regexes.isEmpty() && 
                params.content.regexes.isEmpty() &&
                params.content_type.regexes.isEmpty()) {
                throw new IllegalArgumentException(
                        "Failed to configure " + getClass().getSimpleName() +
                        ". At least one regular expression needs to be provided.");
            }
            return new RegexTargetClassifier(params);
        }
Classify whether a page is relevant by matching lists of regular expressions against multiples
fields of the web page.
ache/src/main/java/achecrawler/target/classifier/RegexTargetClassifier.java