I have implemented a producer consumer problem using BlockingQueue. In this, producer post some tasks at different interval to blocking queue and multiple consumers take that task to process it. My producer code is working fine but my consumer object is throwing error. I am really new to multithreading. I shall be thankful for help.
Producer
public class Producer_Events implements Runnable{
private BlockingQueue<ArrayList<String>> queue;
ArrayList<String> batch_list = new ArrayList<String>();
public Producer_Events(BlockingQueue<ArrayList<String>> queue,ArrayList<String> batch_list) {
this.queue = queue;
this.batch_list = batch_list;
}
public void run() {
try {
// do all the shit
ArrayList<Long> tymstamp = new ArrayList<Long>();
// read timestamp from a file and as per timestamp put value in blockingqueue
//if timestamp ended put a variable named poison to terminate the thread for both producer and consumer
System.out.println("Timestamp added");
for (int m = 0; m<batch_list.size();m++){
String operator = new String();
operator = batch_list.get(m);
ArrayList<String> batch1 = new ArrayList<>();
Thread.sleep(100);// timestamp to add value in blockqueu
batch1.add(operator);
if(m!=batch_list.size()){
queue.put(batch1);
System.out.println("Event Added: "+ m);
}
else{
// inject a poison
ArrayList<String> batch2 = new ArrayList<>(-1);
queue.put(batch2);
System.out.println("Producer STOPPED.");
}
}
} catch (InterruptedException e) {
e.printStackTrace();
} catch (NumberFormatException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}}
Consumer Code
public class ConsumerWorker implements Runnable {
private BlockingQueue<ArrayList<String>> inputQueue;
// private final static ArrayList<String> POISON = new ArrayList<String>();
public ConsumerWorker(BlockingQueue<ArrayList<String>> inputQueue) {
this.inputQueue = inputQueue;
}
@Override
public void run() {
// worker loop keeps taking en element from the queue as long as the
// producer is still running or as
// long as the queue is not empty:
System.out.println("Check loop");
while (true) {
System.out.println("Consumer " + Thread.currentThread().getName()
+ " START");
try {
ArrayList<String> queueElement = inputQueue.take();
System.out.println("Event Send to Crowd: ");
if (queueElement.isEmpty()) {
break;
} else {
System.out.println("DO Processing");
}
} catch (InterruptedException e) {
System.out.println("Interrupted.");
}
System.out.println("Throwing exception ...");
throw new RuntimeException();
}
}}
MAIN FUnction
public class test {
/**
* @param args
*/
public static void main(String[] args) {
ArrayList<String> batch_list = new ArrayList<>();
for (int i=0;i<10;i++){
batch_list.add("OK");
}
// block queue of size 20
BlockingQueue<ArrayList<String>> queue = new ArrayBlockingQueue<ArrayList<String>>(20);
// creating multiple consumers to access blockqueue
ThreadPoolExecutor executor = (ThreadPoolExecutor) Executors.newFixedThreadPool(2);
Producer_Events producer = new Producer_Events(queue,batch_list);
ConsumerWorker consumer = new ConsumerWorker(queue);
System.out.println("OK");
new Thread(producer).start();
executor.execute(consumer);
/*Thread myThread = new Thread(new ConsumerWorker(queue));
//ConsumerWorker consumer = new ConsumerWorker(queue);
myThread.setUncaughtExceptionHandler(new Thread.UncaughtExceptionHandler() {
public void uncaughtException(Thread myThread, Throwable e) {
System.out.println(myThread.getName() + " throws exception: " + e);
}
});*/
}}
ERROR
