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How to parse URL's simultaneously in constructor?

I have a class called "Parser" that can be used to get a price from a url and parse it into an integer.
I then have other classes which uses those variables to create objects. Problem is that because it is running serially it is very slow.
How do I get them to parse the URL's in parallel?
public class Parser {
public static int getPrice(String url) {
String price = "";
try {
Document doc = Jsoup.connect(url).get();
price = doc.select("h3").select("span").attr("title");
} catch (IOException e) {
e.printStackTrace();
}
return parseInt(price);
}
public static double parseDouble(String parseMe) {
NumberFormat ukFormat = NumberFormat.getNumberInstance(Locale.UK);
double parsed = 0;
try {
parsed = ukFormat.parse(parseMe).doubleValue();
} catch (ParseException e) {
e.printStackTrace();
}
return parsed;
}
}
//Here is an example of the class
public class Example(){
private int field1, field2;
public Example(String url1, String url2){
field1=Parser.getPrice(url1);
field2=Parser.getPrice(url2);
}
}

If you'd like the getPrice calls to run asynchronously, you can use ExecutorService, like so:
public Example(String url1, String url2) {
// Create executorService.
ExecutorService executorService = Executors.newWorkStealingPool();
// Submit both tasks to executorService.
Future<Integer> future1 = executorService.submit(new Callable<Integer>() {
#Override
public Integer call() throws Exception {
return Parser.getPrice(url1);
}
});
Future<Integer> future2 = executorService.submit(new Callable<Integer>() {
#Override
public Integer call() throws Exception {
return Parser.getPrice(url2);
}
});
// Shutdown executorService. (It will no longer accept tasks, but will complete the ones in progress.)
executorService.shutdown();
// Handle results of the tasks.
try {
// Note: get() will block until the task is complete
field1 = future1.get();
field2 = future2.get();
} catch (InterruptedException e) {
// TODO Handle it
} catch (ExecutionException e) {
// TODO Handle it
}
}

I had exactly the same case, for me I had to had them to parse the two URL in the same function , and instead of returning an Integer, it returns instead an array of two integers, and it was more fast.
in your case I would suggest working with CyclicBarrier in a way that your code would look like:
final CyclicBarrier cb = new CyclicBarrier(2); // the parameter 2 is the number of threads that will invode the await method
long startTime = System.nanoTime();// this is just the start time to measure how many it took
Thread t1 = new Thread(){
public void run(){
try {
cb.await();
int field1 = Parser.getPrice(url1);
} catch (InterruptedException e) {
e.printStackTrace();
} catch (BrokenBarrierException e) {
e.printStackTrace();
}
}};
Thread t2 = new Thread(){
public void run(){
try {
cb.await();
int field2 = Parser.getPrice(url2);
} catch (InterruptedException e) {
e.printStackTrace();
} catch (BrokenBarrierException e) {
e.printStackTrace();
}
}};
t1.start();
t2.start();
long endTime = System.nanoTime();// end time of execution
long duration = (endTime - startTime);
System.out.println(duration);

Various threads

i'm trying create a thread, which return a value, the process is running correctly but my screen is still locked. I want a thread that return a value but my main thread continues running.
I've done that:
public void showPartidas(int maximumDistance){
ExecutorService es = Executors.newFixedThreadPool(1);
Future<ArrayList<Partida>> partidas= es.submit(new FilterPartidas(maximumDistance));
try {
loadInListView(partidas.get());
} catch (InterruptedException e) {
e.printStackTrace();
} catch (ExecutionException e) {
e.printStackTrace();
}
es.shutdown();
}
class FilterPartidas implements Callable<ArrayList<Partida> > {
private final int distance;
private ArrayList<Partida> partidas;
FilterPartidas(int distance) {
this.distance = distance;
}
#Override
public ArrayList<Partida> call() throws Exception {
partidas=null;
Download load = new Download();
Date fecha = new Date();
DateFormat fechaFormat = new SimpleDateFormat("yyyy-MM-dd");
String query = "select * from partidas where fecha >='"+fechaFormat.format(fecha)+"'";
partidas=load.obtainPartidas(query, distance, myPosition);
return partidas;
}
}

partidas.get() action is the cause that main thread is waiting for the completion of Callable method in executor. If you want main thread are still running during Callable action execution you must place partidas.get() action into dedicated separate thread e.g.:
replace
Future<ArrayList<Partida>> partidas= es.submit(new FilterPartidas(maximumDistance));
try {
loadInListView(partidas.get());
} catch (InterruptedException e) {
e.printStackTrace();
} catch (ExecutionException e) {
e.printStackTrace();
}
into
final Future<ArrayList<Partida>> partidas= es.submit(new FilterPartidas(maximumDistance));
new Thread(new Runnable() {
#Override
public void run() {
try {
loadInListView(partidas.get());
} catch (InterruptedEArrayList<Partida>xception e) {
e.printStackTrace();
} catch (ExecutionException e) {
e.printStackTrace();
}
}
}).start();
or similar action with threads (maybe using executor, Runnable, etc).
Or you can change you logic (if possible) and hide call to method from Callable into Runnable class. E,g.:
ExecutorService es = Executors.newFixedThreadPool(1);
es.submit(new Runnable() {
#Override
public void run() {
ArrayList<Partida> partidas = logic from you Callable call;
loadInListView(partidas);
}
});

How can I make the thread sleep for a while and then process all the messages?

I'm writing an Android app that uses two threads. One is UI thread and the other handles server communication. Is it possible for the other thread to wait for a specified amount of time and then process all the messages that have arrived and then wait again?
I need this so that I can collect different data and send it to server in one session.
I've build my thread with HandlerThread but now I'm stuck. Can anyone point me to the right direction?
This is the code I'm using inside the second thread:
public synchronized void waitUntilReady() {
serverHandler = new Handler(getLooper()){
public void handleMessage(Message msg) { // msg queue
switch(msg.what) {
case TEST_MESSAGE:
testMessage(msg);
break;
case UI_MESSAGE:
break;
case SERVER_MESSAGE:
break;
default:
System.out.println(msg.obj != null ? msg.obj.getClass().getName() : "is null");
break;
}
}
};
}
EDIT:
I resolved my issue by going with Thread instead of HandlerThread and using queue.
I'm new to programming so I apologize for any horrenous errors but here's the code I ended up using.
public class ServiceThread extends Thread {
// TODO maybe set the thread priority to background?
static ServiceThread sThread = new ServiceThread(); // service thread instance
private volatile Handler mainHandler;
//
public Thread mainThread;
private boolean OK = true;
public Queue<MessageService> msgQueue;
private ThreadPoolExecutor exec;
private ServiceThread() { }
#Override
public void run() {
synchronized (this){
msgQueue = new ConcurrentLinkedQueue<MessageService>();
notifyAll();
}
mainHandler = new Handler(Looper.getMainLooper());
ThreadPoolExecutor exPool = (ThreadPoolExecutor) Executors.newFixedThreadPool(2);
exec = exPool;
// MAIN LOOP
try {
while(OK) {
getMessagesFromQueue();
Thread.sleep(3000);
}
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
//end of loop
}
public void ProcessMessage(MessageService message) {
System.err.println("ProcessMessage with command: " + message.command);
}
/** Called from the Main thread. Waits until msgQueue is instantiated and then passes the reference
* #return Message Queue
*/
public Queue<MessageService> sendQueue() {
synchronized (this){
while(msgQueue == null) {
try {
wait();
} catch (InterruptedException e) {
// TODO Auto-generated catch block -- move the try block!
e.printStackTrace();
}
}
}
return msgQueue;
}
public void setOkFalse () {
if (OK == true)
OK = false;
}
// Message handling methods
/** Priority message from UI thread, processed in another thread ASAP.
* Should be used on commands like getBigPicture or getPics when cached pics are running out
* or upload picture etc.
* #param message - Message should always be MessageService class
* TODO check that it really is.
*/
public void prioTask (MessageService message) {
final MessageService taskMsg = message;
Runnable task = new Runnable() {
#Override
public void run(){
ProcessMessage(taskMsg);
}
};
exec.execute(task);
}
/**
* Gets messages from queue, puts them in the list, saves the number of messages retrieved
* and sends them to MessageService.handler(int commands, list messageList)
* (method parameters may change and probably will =) )
*/
public void getMessagesFromQueue() {
int commands = 0;
ArrayList <MessageService> msgList = new ArrayList <MessageService>();
while(!msgQueue.isEmpty()) {
if(msgQueue.peek() instanceof MessageService) {
//put into list?
msgList.add(msgQueue.remove());
commands++;
} else {
//Wrong type of message
msgQueue.remove();
System.err.println("getMessagesFromQueue: Message not" +
" instanceof MessageService, this shouldn't happen!");
}
}
if (commands > 0) {
HTTPConnection conn;
try {
conn = new HTTPConnection();
MessageService.handleSend(commands, msgList, conn);
conn.disconnect();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}
P.S. This is also my first post here. Should I mark it solved or something? How?

Invoke more than one webservice using separate thread in java?

I have to call more than one webservice in one method each webservice is executed by separate thread in concurrent/parellel. Every web service will return one ArrayList. Note: may chance some webservices will fail or take more time process response in this case i have to skip these failure result. How can I achieve this? I tried this sample code.
public class MultiThreadsEx{
public class Task implements Runnable {
private Object result;
private String id;
int maxRowCount = 0;
public Task(String id) {
this.id = id;
}
public Object getResult() {
return result;
}
public void run() {
try {
System.out.println("Running id=" + id+" at "+Utilities.getCurrentJavaDate("DD/MM/YYYY HH:MM:SS"));
if(id.equalsIgnoreCase("1")){
/**Getting Details from Amazon WS*/
maxRowCount = AmazonUtils.getweather(cityname);
}else if(id.equalsIgnoreCase("2")){
/**Getting Details from Google WS* /
maxRowCount = GoogleUtils.getWeather(cityName);
}
// call web service
//Thread.sleep(1000);
//result = id + " more";
result = maxRowCount;
} catch (InterruptedException e) {
// TODO do something with the error
throw new RuntimeException("caught InterruptedException", e);
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
public static void runInParallel(Runnable runnable1, Runnable runnable2) {
try {
Thread t1 = new Thread(runnable1);
Thread t2 = new Thread(runnable2);
t1.start();
t2.start();
} catch (Exception e) {
// TODO do something nice with exception
throw new RuntimeException("caught InterruptedException", e);
}
}
public void foo() {
try {
Task task1 = new Task("1");
Task task2 = new Task("2");
runInParallel(task1, task2);
System.out.println("task1 = " + task1.getResult()+" at "+Utilities.getCurrentJavaDate("DD/MM/YYYY HH:MM:SS"));
System.out.println("task2 = " + task2.getResult()+" at "+Utilities.getCurrentJavaDate("DD/MM/YYYY HH:MM:SS"));
} catch (Exception e) {
//TODO Auto-generated catch block
e.printStackTrace();
}
}
But run() return type is void so how can return result? Examples are highly appreciated. I am new to multithread/concurrent threads concept so if I'm doing anything wrong, please point me in the right direction.

Consider replacing Runnable - run with Callable - call. This will allow you to return a result from your thread task:
public class Task implements Callable<Object> {
private Object result;
public Object call() {
// compute result
return result;
}
}
Now use an ExecutorService:
public static void runInParallel(Callable<Object> c1, Callable<Object> c2) {
ExecutorService exec = Executors.newFixedThreadPool(2);
Future<Object> f1 = exec.submit(c1);
Future<Object> f2 = exec.submit(c2);
}
Later in the code you can use f1.get() and f2.get() to wait for the results of the tasks.

The usual way to communicate the results of a Runnable back to the object which created it is by passing the creating object to the constructor of the Runnable. When the task is finished, you can call a method in the creating object and pass the result data.

Thread.join() not working in Android?

I want to create long-running application for performing various tasks on different threads. Each task should have one-minute timeout. Here is my implementation:
runner = new Thread(new Runnable() {
#Override
public void run() { }
// some actions here
});
runner.start();
startJoin = System.currentTimeMillis();
runner.join(TIMEOUT);
stopJoin = System.currentTimeMillis();
if ((stopJoin - startJoin) >= TIMEOUT)
throw new TimeoutException("Timeout when reading the response from process");
In general case it is working and throwing TimeoutExceptions, but sometimes it is doing nothing after even few hours. So the questions is if Thread.join is reliable on Android?
I have an idea to use Thread.wait and notify instead of that, what is the better way in your opinion?

Refer below program.
public static void main(String[] args) throws InterruptedException {
long TIMEOUT=100;
Thread runner = new Thread(new Runnable() {
#Override
public void run() {
for(;;){
System.out.println("running ");
}
}
// some actions here
});
runner.start();
long startJoin = System.currentTimeMillis();
runner.join(TIMEOUT);
long stopJoin = System.currentTimeMillis();
if ((stopJoin - startJoin) >= TIMEOUT)
try {
throw new Exception("Timeout when reading the response from process");
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
System.out.println("Running Thread");
}
This program never ends that means your logic is incorrect.
Better to use TimerTask.

I prefer doing all time base task using Timer and TimerTask. Check the following code and probably this should be useful to you:
Timer t =new Timer();
t.schedule(new TimerTask() {
#Override
public void run() {
//The task you want to perform after the timeout period
}
}, TIMEOUT);
EDIT
I am giving a try at solving your problem. I am using the code written by #amicngh as my base code and have done some modifications to it. I presume that after the TIMEOUT period you want to close the running thread. Check the following code runs fine and the explanation that follows:
public class ThreadTest {
public static void main(String[] args) throws InterruptedException {
final long TIMEOUT=100;
final long startJoin = System.currentTimeMillis();
Thread runner = new Thread(new Runnable() {
long stopJoin;
#Override
public void run() {
try{
for(;;){
System.out.println("running ");
stopJoin = System.currentTimeMillis();
if ((stopJoin - startJoin) >= TIMEOUT){
throw new Exception();
}
}
}
catch (Exception e) {
// TODO: handle exception
}
}
// some actions here
});
runner.start();
synchronized (ThreadTest.class) {
ThreadTest.class.wait(TIMEOUT);
}
/*if ((stopJoin - startJoin) >= TIMEOUT)
try {
throw new Exception("Timeout when reading the response from process");
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}*/
System.out.println("Running Thread");
}
}
The Thread API description says that it is unsafe to destroy or stop (hence both these method has been deprecated) and one of the way to stop a thread is to throw an exception. Hence I am checking for the Timeout inside the runner thread. Now about making the Main thread wait it is done by the 2 lines of code which uses synchronized to synchronize the access to the thread.
Hope this code and explanation solves your problem.