What is _targetTasks is empty?
On 2014年3月6日, at 下午10:28, 李家宏 <[email protected]> wrote:
> hi, all
> i'am using CustomStreamGrouping with very simple mod selection. it thrown
> IndexOutOfBoundsException. From the trace below:
>
> Caused by: java.lang.IndexOutOfBoundsException: null
> at clojure.lang.PersistentVector.arrayFor(PersistentVector.java:106)
> ~[clojure-1.4.0.jar:na]
> at clojure.lang.PersistentVector.nth(PersistentVector.java:110)
> ~[clojure-1.4.0.jar:na]
> at clojure.lang.APersistentVector.get(APersistentVector.java:167)
> ~[clojure-1.4.0.jar:na]
> at bolts.PingPongGrouping.chooseTasks(PingPongGrouping.java:37)
> ~[stormjar.jar:na]
>
> We locate the problem to the CustomStreamGrouping.chooseTasks() function
> which looks like:
>
> @Override
> public List<Integer> chooseTasks(int i, List<Object> values) {
> ArrayList<Integer> boltIds = new ArrayList<Integer>();
> if (values.size() > 0) {
> int hashcode = values.get(0).hashCode();
> int index = hashcode % _targetTasks.size();
> boltIds.add( _targetTasks.get(index)); // here is the problem
> } else {
> boltIds.add( _targetTasks.get(0));
> }
> return boltIds;
> }
>
> @Override
> public void prepare(WorkerTopologyContext context, GlobalStreamId
> streamId, List<Integer> targetTasks) {
> this._targetTasks = targetTasks;
> }
>
> How can it be out of bounds ?
>
> Regards
>
>
> --
> ======================================================
>
> Gvain
>
> Email: [email protected]
>
