having issues with BlockingQueue java , implementation of Storm (Distributed computing)?

Question

This is the code snippt of my input spout for emmiting tuple to a processing noded for stream processing over a cluster. The problem is The BlockingQueue is throwing InterruptedException .

private SpoutOutputCollector collector;
public BlockingQueue<String> blockingQueue = new LinkedBlockingQueue<String>();

public boolean isDistributed() {
    return true;
    }


public void open(@SuppressWarnings("rawtypes") final Map conf, final TopologyContext context,
final SpoutOutputCollector collector) {

    this.collector=collector;

}

@Override
public void nextTuple() {


    try {
        //Utils.sleep(100);
        collector.emit(new Values("Single Temperature Reading", blockingQueue.take()));
    } catch (InterruptedException e) {
        e.printStackTrace();
    }



}

public void readInputfile() throws IOException, InterruptedException{
    FileInputStream file = new FileInputStream("/home/529076/Desktop/Temperature");
    DataInputStream readDate=new DataInputStream(file);
    BufferedReader readText=new BufferedReader(new InputStreamReader(readDate));

    String line;
    String singleReading = null;
    while((line=readText.readLine())!=null){
         singleReading=line;
         blockingQueue.add(singleReading);

    }

}
@Override
public void declareOutputFields(OutputFieldsDeclarer declarer) {
    declarer.declare(new Fields("Single Temperature Reading"));
}

The exception description is as followes :---

java.lang.InterruptedException10930 [Thread-20] INFO backtype.storm.util - Async loop interrupted!

at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.reportInterruptAfterWait(AbstractQueuedSynchronizer.java:1961)
at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await(AbstractQueuedSynchronizer.java:1996)
at java.util.concurrent.LinkedBlockingQueue.take(LinkedBlockingQueue.java:399)
at com.tcs.storm.test.InputStreamSpout.nextTuple(InputStreamSpout.java:65)
at backtype.storm.daemon.task$fn__3349$fn__3404.invoke(task.clj:413)

And The nextTuple(InputStreamSpout.java:65 is ------>

        collector.emit(new Values("Single Temperature Reading", blockingQueue.take()));

Thanks

Answer 1

The error is due to the fact -- The BlockingQueue was not initilaized in the output collector;

Answer 2

In Storm, it is recommendable to initialize fields of Bolts/Spouts in the prepare()/open() methods.

The reason for this is that Bolts/Spouts are created on the node from which you upload the topology: your BlockingQueue would be constructed there. Bolts/Spouts are then then serialized and distributed to the worker nodes, where they are deserialized. It's possible that this process of serializing/deserializing fails to preserve all the properties of fields that are set at construction of the Bolt/Spout. Fields initialized in prepare() or open() do not have this issue.