I am getting a runtime exception on line 40 when running the code.
the following is the code.
import java.util.concurrent.BlockingQueue;
import java.io.PrintStream;
import java.util.Date;
public class Consumer extends
Thread {
private BlockingQueue blockingQueue;
private
String consumerName;
private PrintStream printStream;
public Consumer(String consumerName, BlockingQueue blockingQueue, PrintStream printStream)
{
consumerName = this.consumerName;
blockingQueue = this.blockingQueue;
printStream = this.printStream;
}
public void run()
{
while (true)
{
try
{
if (blockingQueue != null)
{
printStream.println(this.consumerName + blockingQueue.take());
}
else {
printStream.println("Blocking Queue Seems to be empty ");
}
//String time = String.format("%tc",new Date());
//printStream.println("Getting item on BlockingQueue at time: " + time);
}
catch (InterruptedException ie)
{
ie.printStackTrace();
}
}
}
}
import java.util.Date;
import java.util.concurrent.BlockingQueue;
import java.util.Random;
import java.io.PrintStream;
public class Producer extends Thread
{
private BlockingQueue<String> blockingQueue;
private PrintStream printStream;
public Producer(BlockingQueue<String> blockingQueue, PrintStream printStream)
{
this.printStream = printStream;
this.blockingQueue = blockingQueue;
}
public void run()
{
try
{
while(true)
{
String time = String.format("%tc",new Date());
printStream.println("Putting item on BlockingQueue at time: " + time);
blockingQueue.put("Enqueued at: " + time);
Random generator = new Random();
int randomSleep = generator.nextInt(5) + 1;
Thread.sleep(randomSleep * 100);
}
}
catch (InterruptedException e)
{
e.printStackTrace();
}
}
}
public class TestBlockingQueue
{
public static void main(String args[])
{
BlockingQueue<String> blockingQueue = new LinkedBlockingQueue<String>();
Producer producer = new Producer(blockingQueue, System.out);
//Producer producerB = new Producer(blockingQueue, System.out);
Consumer consumerA = new Consumer("ConsumerA", blockingQueue, System.out);
//Consumer consumerB = new Consumer("ConsumerB", blockingQueue, System.out);
//Consumer consumerC = new Consumer("ConsumerC", blockingQueue, System.out);
//Consumer consumerD = new Consumer("ConsumerD", blockingQueue, System.out);
producer.start();
//producerB.start();
if (consumerA == null)
{
consumerA = new Consumer("ConsumerA", blockingQueue, System.out);
consumerA.start();
}
consumerA.start();
//consumerB.start();
//consumerC.start();
//consumerD.start();
}
}// End Class TestBlockingQueue
I am not sure what is wrong but the code would not work when executed. except that the producer class works but the consumer would not throwing an Nullpointer Exception. Could someone please help.
Many Thanks
Arun
