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POHow is this java app running multiple threads without extending threads or implementing runnable?
 

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  1. POHow is this java app running multiple threads without extending threads or implementing runnable?
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    <p>I'm learning Java and was able to do a bit of multi-threading with my existing apps using runnable. I was now looking at disruptor(to share variables between threads), but I can't figure out how the author is actually spawning threads.</p> <p>I see he is using Executor, which I use to submit runnable classes to in my program but in this example there is no submit(or runnable). I only learned what I know from the Oracle tutorials and they mention the only two ways is to extend threads or implement runnable(I don't see either here, but he does submit executor to disruptor, which maybe how he's threading?). Am I missing something or is this person doing it in a different way? My end goal is to understand this code(which works perfectly) so I can apply it to my existing (using runnable) code.</p> <p>Here's the code in question:</p> <p><a href="http://www.kotancode.com/2012/01/06/hello-disruptor/" rel="nofollow">App.java</a></p> <pre><code>import com.lmax.disruptor.*; import com.lmax.disruptor.dsl.*; import java.util.concurrent.Executor; import java.util.concurrent.ExecutorService; import java.util.concurrent.Executors; import java.util.concurrent.ThreadPoolExecutor; public class App { private final static int RING_SIZE = 1024 * 8; private static long handleCount = 0; private final static long ITERATIONS = 1000L * 1000L * 300L; private final static int NUM_EVENT_PROCESSORS = 8; private final static EventHandler&lt;ValueEvent&gt; handler = new EventHandler&lt;ValueEvent&gt;() { public void onEvent(final ValueEvent event, final long sequence, final boolean endOfBatch) throws Exception { handleCount++; } }; public static void main(String[] args) { System.out.println("Starting disruptor app."); ExecutorService executor = Executors.newFixedThreadPool(NUM_EVENT_PROCESSORS); Disruptor&lt;ValueEvent&gt; disruptor = new Disruptor&lt;ValueEvent&gt;(ValueEvent.EVENT_FACTORY, executor, new SingleThreadedClaimStrategy(RING_SIZE), new SleepingWaitStrategy()); disruptor.handleEventsWith(handler); RingBuffer&lt;ValueEvent&gt; ringBuffer = disruptor.start(); long start = System.currentTimeMillis(); long sequence; ValueEvent event; for (long x=0; x&lt;ITERATIONS; x++) { sequence = ringBuffer.next(); event = ringBuffer.get(sequence); event.setValue(x); ringBuffer.publish(sequence); } final long expectedSequence = ringBuffer.getCursor(); while (handleCount &lt; expectedSequence) { } long opsPerSecond = (ITERATIONS * 1000L) / (System.currentTimeMillis() - start); System.out.printf("op/s: %d, handled: %d", opsPerSecond, handleCount); } } </code></pre> <p>Update: if Disruptor is handling the spawning of threads then how can I submit my existing runnable class to it? or do I need to rework the code again? Sorry I'm a bit confused on if disruptor is going to work with existing code or if I need to completely change my stuff for it.</p>
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    1. USError_404
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    1. COThe executer apparently spawns threads to execute. And it is passed to the Disruptor. You do not provide any information about that class, but since it has access to the executor it certainly can pass jobs into it.
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      1. POHow is this java app running multiple threads without extending threads or implementing runnable?
      1. USuser1252434
    2. COIf all you need is to handle 100,000 tasks per second or less, using an ExecutorService alone is likely to be simpler. If you be able to handle millions of tasks per second, then the Disruptor is a good solution. If you need to support this high level of performance, changing a little of your code to fit into its processing model shouldn't bother you. I suspect that what you need is the simplest solution possible, which is to use just an ExecutorService.
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      1. POHow is this java app running multiple threads without extending threads or implementing runnable?
      1. USPeter Lawrey
    3. CO@PeterLawrey my program is a simple math program but it refers to a shared hashmap. The problem is there are several million lookups per second(and some writes based on those lookups. I was using redis for a while and got it up to 60,000 but it wasn't enough). I thought disruptor fit the bill but I think your right I'll try ExecutorService and then go from there.
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