public class CrawlRequest {
	@NotNull
	private Integer jobId;

	@NotEmpty
	private List<String> urls;

	@Min(0)
	@Max(1)
	private Integer priority;

	@JsonFormat(shape = JsonFormat.Shape.STRING, pattern = "yyyy-MM-dd")
	private Date crawlDate;

	private List<KeyValue> additionalData;
}

@Data
class KeyValue {
	String key;
	String value;
}

class ExampleProcessor {
	final String RABBITMQ_MESSAGE_STRING_FORMAT = "%s\tjobId=%d\tcrawlDate=%s";

	public void process(final String url, CrawlRequest crawlRequest) {

		Map<String, String> defaultValueConfig = null; // get from config file
		Set<String> supportedKeys = null; // get from config file

		final int jobId = crawlRequest.getJobId();
		final Date crawlDate = crawlRequest.getCrawlDate() == null ? new Date() : crawlRequest.getCrawlDate();
		Set<KeyValue> values = crawlRequest.getAdditionalData().stream().filter(kv -> supportedKeys.contains(kv.getKey())).collect(Collectors.toSet());

		final List<String> valuesKeyFormatted = values.stream().map(kv -> kv.getKey() + "=%s").collect(Collectors.toList());
		final List<String> valuesFormatted = values.stream().map(kv -> kv.getValue()).collect(Collectors.toList());

		final String request = String.format(RABBITMQ_MESSAGE_STRING_FORMAT + String.join("\t", valuesKeyFormatted), url, jobId, crawlDate, valuesFormatted);

	}
}