Intendia - Driver files download example - Java 11 no dependencies

DriverDownloadService.java

import static java.nio.charset.StandardCharsets.ISO_8859_1;
import static java.nio.file.StandardOpenOption.CREATE;
import static java.nio.file.StandardOpenOption.TRUNCATE_EXISTING;
import static java.nio.file.StandardOpenOption.WRITE;
import static java.util.stream.Collectors.toList;

import java.net.URI;
import java.net.http.HttpClient;
import java.net.http.HttpRequest;
import java.net.http.HttpResponse.BodyHandlers;
import java.nio.file.Path;
import java.util.Base64;
import java.util.concurrent.TimeUnit;
import java.util.function.BiFunction;
import java.util.prefs.Preferences;

/** {@code Usage: java DriverDownloadService.java <API_KEY>} */
public class DriverDownloadService {
    public static final String INTENDIA_API = "https://igp.intendia.com/api";
    public static final String LAST_DFILE_KEY = "intendia.lastDriverFileId";

    public static void main(String[] args) throws Exception {
        if (args.length == 0 || args[0].isEmpty()) throw new IllegalAccessException("api-key required");
        var client = HttpClient.newHttpClient(); // basic auth using the api-key…
        var credentials = "Basic " + Base64.getEncoder().encodeToString((args[0] + ":X").getBytes(ISO_8859_1));
        BiFunction<String, String, HttpRequest.Builder> REQ = (path, accept) -> HttpRequest
                .newBuilder(URI.create(INTENDIA_API + "/" + path))
                .header("Authorization", credentials).header("Accept", accept);
        var donwloadTo = BodyHandlers.ofFileDownload(Path.of(".")/*current folder*/, CREATE, TRUNCATE_EXISTING, WRITE);
        int lastDrvId = Preferences.userRoot().getInt(LAST_DFILE_KEY/* last processed driver file Id */, 0);
        while (true) {
            System.out.println("requesting file list since " + lastDrvId + "…");
            var files = client.send(REQ.apply("dtco/driverFiles?fileIdSince=" + lastDrvId + "&max=3&fields=fileId",
                    "text/csv").build(), BodyHandlers.ofLines()).body().collect(toList());
            for (var fileId : files) {
                System.out.println("downloading file " + fileId + "…");
                client.send(REQ.apply("dtco/driverFiles/" + fileId, "application/octet-stream").build(), donwloadTo);
                lastDrvId = Integer.parseInt(fileId);
                Preferences.userRoot().putInt(LAST_DFILE_KEY, lastDrvId);
            }
            if (files.isEmpty()) {
                System.out.println("all files download, retrying in 5minutes… ");
                Thread.sleep(TimeUnit.MINUTES.toMillis(5));
            }
        }
    }
}