Package net.imglib2.parallel

Interface TaskExecutor

  • All Superinterfaces:
    java.lang.AutoCloseable
    All Known Implementing Classes:
    DefaultTaskExecutor, SequentialTaskExecutor
    public interface TaskExecutor
extends java.lang.AutoCloseable
    TaskExecutor is recommended to be used in image processing algorithms instead of ExecutorService. It's simpler to use, and allows single threaded execution. 

     

 // Example of a multi threaded method that fills an image with ones.
 public void fillWithOnes( RandomAccessibleInterval< IntType > image, TaskExecutor taskExecutor )
 {
     int numTasks = taskExecutor.suggestNumberOfTasks();
     List< RandomAccessibleInterval< IntType > > chunks = splitImageIntoChunks( image, numTasks );

     // The TaskExecutor executes the forEach method in multi threads, if requested.
     taskExecutor.forEach( chunks, chunk -> {
         for ( IntType pixel : Views.iterable( chunk ) )
             pixel.setOne();
     } );
 }

 // The method can be run multi threaded or single threaded
 fillWithOnes( image, TaskExecutors.singleThreaded() );
 fillWithOnes( image, TaskExecutors.multiThreaded() );

    • Method Summary

      All Methods Instance Methods Abstract Methods 
      Modifier and Type Method Description
      void close()  
      <T> void forEach​(java.util.List<? extends T> parameters, java.util.function.Consumer<? super T> task)
      Like runAll(List) but - instead of a list of tasks - it takes a list of parameters and a function that is called for each of the parameters.
      <T,​R>
      java.util.List<R>      		 forEachApply​(java.util.List<? extends T> parameters, java.util.function.Function<? super T,​? extends R> task)
      Like forEach(List, Consumer) but collects the results.
      java.util.concurrent.ExecutorService getExecutorService()
      Get the underlying ExecutorService.
      int getParallelism()
      Get the number of threads that are used for execution.
      void runAll​(java.util.List<java.lang.Runnable> tasks)
      This method will execute the given list of tasks.
      int suggestNumberOfTasks()
      If there is a big task that could be split into sub tasks for parallelization, this method gives you a reasonable number of sub tasks.

    • Method Detail

      • getParallelism

        int getParallelism()
        Get the number of threads that are used for execution.

      • suggestNumberOfTasks

        int suggestNumberOfTasks()
        If there is a big task that could be split into sub tasks for parallelization, this method gives you a reasonable number of sub tasks.

        A single threaded TaskExecutor will return 1. A multi threaded TaskExecutor will usually return 4 times the number of threads.

      • runAll

        void runAll​(java.util.List<java.lang.Runnable> tasks)
        This method will execute the given list of tasks. A single threaded TaskExecutor will execute the tasks one after the other. A multi threaded TaskExecutor will distribute the tasks to the threads. The method blocks until all tasks are completed.

      • forEach

        <T> void forEach​(java.util.List<? extends T> parameters,
                 java.util.function.Consumer<? super T> task)
        Like runAll(List) but - instead of a list of tasks - it takes a list of parameters and a function that is called for each of the parameters.

      • forEachApply

        <T,​R> java.util.List<R> forEachApply​(java.util.List<? extends T> parameters,
                                           java.util.function.Function<? super T,​? extends R> task)
        Like forEach(List, Consumer) but collects the results.

      • getExecutorService

        java.util.concurrent.ExecutorService getExecutorService()
        Get the underlying ExecutorService. This is not always a fully functional ExecutorService: Especially the methods ExecutorService.shutdown() and ExecutorService.awaitTermination(long, TimeUnit) must not be used.

      • close

        void close()
        Specified by:
        close in interface java.lang.AutoCloseable