Develop Reference

Right way to run tasks concurrently

I am currently facing the following issue with Java concurrency. I want to parse a friend list on a website, then search for the friends of the friends etc. recursively.
Here it is represented visually:
0
/|\
0 0 0
/|\
0 0 0
I came up with a solution but it does not perform as well as I expected, I assume my logic might be somewhat faulty.
private ArrayList<String> getUserFriendsProfileURLs(final String uri, final int indexOfDeep, int foldenesLevel)
throws IOException {
var usersURIs = getUsers(uri); //long network call
ArrayList<String> uris = new ArrayList<>();
uris.addAll(usersURIs);
if (indexOfDeep != foldenesLevel) {
List<CompletableFuture<ArrayList<String>>> futures = new ArrayList<>();
usersURIs.forEach(useruri -> {
CompletableFuture<ArrayList<String>> future = CompletableFuture.supplyAsync(new Supplier<>() {
public ArrayList<String> get() {
var friendsOfUser = new ArrayList<String>();
try {
friendsOfUser = getUserFriendsProfileURLs(useruri, indexOfDeep, 1 + foldenesLevel);
} catch (IOException e) {
throw new IllegalStateException(e);
}
return friendsOfUser;
}
});
futures.add(future);
});
CompletableFuture<Void> allFuturesResult = CompletableFuture
.allOf(futures.toArray(new CompletableFuture[futures.size()]));
var res = allFuturesResult.thenApply(v -> futures.stream().map(CompletableFuture::join).toList());
try {
uris = (ArrayList<String>) res.get().stream().flatMap(Collection::stream).collect(Collectors.toList());
} catch (InterruptedException | ExecutionException e) {
e.printStackTrace();
}
}
return uris;
}
I wrote 2nd version of function:
/**
* getUserFriendsProfileURLs returns list of friends of given steamid DFS
* algorithm is used
*
*/
private ArrayList<String> getUserFriendsProfileURLs(final int indexOfDeep, int foldenesLevel,
ArrayList<String> usersURIs) throws IOException {
ArrayList<String> uris = new ArrayList<>();
uris.addAll(usersURIs);
if (indexOfDeep != foldenesLevel) {
List<CompletableFuture<ArrayList<String>>> futures = new ArrayList<>();
usersURIs.forEach(useruri -> {
CompletableFuture<ArrayList<String>> future = CompletableFuture.supplyAsync(new Supplier<>() {
public ArrayList<String> get() {
ArrayList<String> ur = null;
try {
ur = getUsers(useruri); // long network call
} catch (IOException e1) {
e1.printStackTrace();
}
return ur;
}
});
futures.add(future);
});
CompletableFuture<Void> allFuturesResult = CompletableFuture
.allOf(futures.toArray(new CompletableFuture[futures.size()]));
var res = allFuturesResult.thenApply(v -> futures.stream().map(CompletableFuture::join).toList());
try {
uris = (ArrayList<String>) res.get().stream().flatMap(Collection::stream).collect(Collectors.toList());
uris = getUserFriendsProfileURLs(indexOfDeep, 1 + foldenesLevel, uris);
} catch (InterruptedException | ExecutionException e) {
e.printStackTrace();
}
}
return uris;
}

How do I save the id from chatid with the telegram api

Hello. I'm trying to solve this problem for a while now. For some
reason I keep getting null pointer exception when I try to save a
object in my repository. Below you can see what happens and my
functions.
java.lang.NullPointerException at com.br.einstein.api.service.ApiTelegram.sendMsg(ApiTelegram.java:104)
at
com.br.einstein.api.service.ApiTelegram.onUpdateReceived(ApiTelegram.java:81)
at java.base/java.util.ArrayList.forEach(ArrayList.java:1541) at
org.telegram.telegrambots.meta.generics.LongPollingBot.onUpdatesReceived(LongPollingBot.java:27)
at
org.telegram.telegrambots.updatesreceivers.DefaultBotSession$HandlerThread.run(DefaultBotSession.java:317)
public void onUpdateReceived(Update update) {
ApiEinstein api = new ApiEinstein();
try {
JsonObject objSession = api.getSessionDetails();
String message = update.getMessage().getText();
api.sendChatRequest(objSession);
List < String > list = new ApiEinstein().ReadChatDetails(objSession);
sendMsg(update.getMessage().getChatId().toString(), list.toString());
new ApiEinstein().SendChatMessage(objSession, message);
api.syncChatSession(objSession);
} catch (Exception e) {
e.printStackTrace();
}
}
public synchronized void sendMsg(String chatId, String s) {
SendMessage sendMessage = new SendMessage();
// sendMessage.enableMarkdown(true);
sendMessage.setChatId(chatId);
sendMessage.setText(s);
long id = Long.valueOf(chatId);
Telegram telegram = new Telegram();
telegram.setChatId(id);
repository.save(telegram);
try {
execute(sendMessage);
} catch (TelegramApiException e) {
e.printStackTrace();
}
} ```

JavaFX freeze window

I encountered a problem when I filter a treeView (long process) my application freezes. I tried to do this in a separate thread (Thread), but then I got the error "Not on FX application thread; currentThread = Thread-5"
void InitBtnFind() {
//Event Button Search
btnFind.setOnAction(event -> {
newFind();
if (Config.isRoot()) {
String finalSFilterExt = filterExt.getText();
String finalSearchW = searchWord.getText();
Platform.runLater(() -> {
try {
// imitation of work
Thread.sleep(5000);
fileView.setRoot(treeView.filterChanged(finalSFilterExt, finalSearchW));
} catch (IOException | InterruptedException e) {
e.printStackTrace();
}
System.out.println("lol");
});
}
});
}
You can give a sample code to solve my problem.
P.s. Do not lower my reputation, I am really interested in this matter
P.s. my attempt to do this with thread
//Event Button Search
btnFind.setOnAction(event -> {
newFind();
if (Config.isRoot()) {
String finalSFilterExt = filterExt.getText();
String finalSearchW = searchWord.getText();
if (findThread != null && findThread.isAlive())
findThread.interrupt();
findThread = new Thread(() -> {
try {
fileView.setRoot(treeView.filterChanged(finalSFilterExt, finalSearchW));
} catch (IOException e) {
e.printStackTrace();
}
System.out.println("lol");
});
findThread.setName("findThread");
findThread.setDaemon(true);
findThread.start();
}
System.out.println("kek");
});

I fixed it this way, I don’t know how correct it is. But it worked for me. I hope it will be useful.
//Event Button Search
btnFind.setOnAction(event -> {
newFind();
if (Config.isRoot()) {
String finalSFilterExt = filterExt.getText();
String finalSearchW = searchWord.getText();
if (findThread != null && findThread.isAlive())
findThread.interrupt();
findThread = new Thread(() -> {
try {
Thread.sleep(2000);
System.out.println("++++++++++++++");
var q =treeView.filterChanged(finalSFilterExt, finalSearchW);
Platform.runLater(()->{fileView.setRoot(q);});
} catch (IOException | InterruptedException e) {
e.printStackTrace();
}
});
findThread.setName("findThread");
findThread.setDaemon(true);
findThread.start();
}
});

JAVA Telegram bots api Error getting updates: Conflict: terminated by other long poll or webhook

I am using JAVA Telegram Bot API with Spring framework , I had a method in my HomeController and i had a class that handle all of the incoming messages from users. I got these errors in my spring log,then i got duplicated response from telegram bot API .whats is the problem ?
#PostConstruct
public void initBots() {
ApiContextInitializer.init();
TelegramBotsApi botsApi = new TelegramBotsApi();
BotService botService = new BotService();
try {
botsApi.registerBot(botService);
} catch (TelegramApiException e) {
e.printStackTrace();
}
}
[abrsystem1_bot Telegram Connection] org.telegram.telegrambots.logging.BotLogger.severe
BOTSESSION
org.telegram.telegrambots.exceptions.TelegramApiRequestException:
Error getting updates: [409] Conflict: terminated by other long poll
or webhook at
org.telegram.telegrambots.api.methods.updates.GetUpdates.deserializeResponse(GetUpdates.java:119)
at
org.telegram.telegrambots.updatesreceivers.DefaultBotSession$ReaderThread.getUpdatesFromServer(DefaultBotSession.java:255)
at
org.telegram.telegrambots.updatesreceivers.DefaultBotSession$ReaderThread.run(DefaultBotSession.java:186)
#Override
public void onUpdateReceived(Update update) {
try {
if (update.hasMessage() && update.getMessage().hasText()) {
String message_text = update.getMessage().getText();
String wellcome_text = "برای ثبت نام در سایت شماره تلفن همراه خود را به اشتراک بگذارید";
long chat_id = update.getMessage().getChatId();
if (message_text.equals("/start")) {
try {
SendMessage message = new SendMessage()
.setChatId(chat_id)
.setText(wellcome_text);
ReplyKeyboardMarkup keyboardMarkup = new ReplyKeyboardMarkup();
List<KeyboardRow> keyboard = new ArrayList<KeyboardRow>();
KeyboardRow row = new KeyboardRow();
row.add((new KeyboardButton().setText("اشتراک شماره موبایل").setRequestContact(true)));
keyboard.add(row);
keyboardMarkup.setKeyboard(keyboard);
message.setReplyMarkup(keyboardMarkup);
try {
execute(message);
} catch (TelegramApiException e) {
e.printStackTrace();
}
} catch (Exception e) {
e.printStackTrace();
}
} else if (message_text.equals("تایید مشخصات کاربری")) {
SendMessage sendMessage = new SendMessage();
sendMessage.setChatId(chat_id).setText("اطلاعات مورد تایید قرار گرفت");
try {
execute(sendMessage);
removeMarker(chat_id);
showContactInfo(chat_id, update);
} catch (Exception ex) {
ex.printStackTrace();
}
} else if (message_text.equals("تغییر مشخصات")) {
} else {
showUnknownCommand(chat_id);
}
} else if (update.getMessage().getContact() != null && update.getMessage().getChat() != null) {
long chat_id = update.getMessage().getChatId();
showContactInfo(chat_id, update);
}
} catch (Exception e) {
e.printStackTrace();
}
}

I finally solved my problem after a day!when i was debugging my project with intellij idea on my computer , i created many instances for debug so i got multiple response from same chat id in telegram bot.so boring problem....

Handle reconnection for twitter hbc

I'm having trouble figuring how to deal with disconnections with hbc twitter api. The doc says I need slow down reconnect attempts according to the type of error experienced. Where do I get the type of error experienced? Is it in the msgQueue or the eventQueue or wherever?
#Asynchronous
#Override
public void makeLatestsTweets() {
msgList = new LinkedList<Tweet>();
BlockingQueue<String> msgQueue = new LinkedBlockingQueue<String>(100);
BlockingQueue<Event> eventQueue = new LinkedBlockingQueue<Event>(100);
Hosts hosebirdHosts = new HttpHosts(Constants.SITESTREAM_HOST);
StatusesFilterEndpoint hosebirdEndpoint = new StatusesFilterEndpoint();
userIds = addFollowings();
hosebirdEndpoint.followings(userIds);
Authentication hosebirdAuth = new OAuth1(CONSUMER_KEY, CONSUMER_SECRET,
TOKEN, SECRET);
ClientBuilder builder = new ClientBuilder().hosts(hosebirdHosts)
.authentication(hosebirdAuth).endpoint(hosebirdEndpoint)
.processor(new StringDelimitedProcessor(msgQueue))
.eventMessageQueue(eventQueue);
Client hosebirdClient = builder.build();
hosebirdClient.connect();
while (!hosebirdClient.isDone()) {
try {
String msg = msgQueue.take();
Tweet tweet = format(msg);
if (tweet != null) {
System.out.println(tweet.getTweetsContent());
msgList.addFirst(tweet);
if (msgList.size() > tweetListSize) {
msgList.removeLast();
}
caller.setMsgList(msgList);
}
} catch (InterruptedException e) {
hosebirdClient.stop();
e.printStackTrace();
} catch (JSONException e) {
e.printStackTrace();
}
}
}