Class TaskExecutor

  • public final class TaskExecutor
    extends Object
    Executor wrapper responsible for the execution of concurrent tasks. Used to parallelize search across segments as well as query rewrite in some cases. Exposes a single invokeAll(Collection) method that takes a collection of Callables and executes them concurrently/ Once all tasks are submitted to the executor, it blocks and wait for all tasks to be completed, and then returns a list with the obtained results. Ensures that the underlying executor is only used for top-level invokeAll(Collection) calls, and not for potential invokeAll(Collection) calls made from one of the tasks. This is to prevent deadlock with certain types of pool based executors (e.g. ThreadPoolExecutor).
    WARNING: This API is experimental and might change in incompatible ways in the next release.
    • Constructor Detail

      • TaskExecutor

        public TaskExecutor​(Executor executor)
        Creates a TaskExecutor instance
        executor - the executor to be used for running tasks concurrently
    • Method Detail

      • invokeAll

        public <T> List<T> invokeAll​(Collection<Callable<T>> callables)
                              throws IOException
        Execute all the callables provided as an argument, wait for them to complete and return the obtained results. If an exception is thrown by more than one callable, the subsequent ones will be added as suppressed exceptions to the first one that was caught.
        Type Parameters:
        T - the return type of the task execution
        callables - the callables to execute
        a list containing the results from the tasks execution