[DROIDS-166] SimpleTaskQueueWithHistory is not thread safe

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 0.2.0
• Fix Version/s: 0.2.0
• Component/s: core
• Assignee: Unassigned
• Reporter: Tobias Rübner
• Created: 30/Mar/12 09:53
• Updated: 15/Jun/12 15:17
• Resolved: 15/Jun/12 15:17

Description

The implementation extends java.util.LinkedList which is not thread safe.
Running droids with the MultiThreadedTaskMaster could spawn endless new threads.

Exception in thread "pool-1-thread-12808" java.util.NoSuchElementException
        at java.util.LinkedList.remove(LinkedList.java:788)
        at java.util.LinkedList.removeFirst(LinkedList.java:134)
        at java.util.LinkedList.poll(LinkedList.java:470)
        at org.apache.droids.impl.MultiThreadedTaskMaster$TaskExecutor.run(MultiThreadedTaskMaster.java:336)
        at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
        at java.lang.Thread.run(Thread.java:662)

I fixed this extending the SimpleTaskQueueWithHistory from java.util.concurrent.LinkedBlockingQueue and rewriting the add and offer methods.