Package org.pipecraft.pipes.sync.inter

Class ProgressPipe<T>

  • Type Parameters:
    T - The item data type
    All Implemented Interfaces:
    Closeable, AutoCloseable, BasePipe, Pipe<T>
    public class ProgressPipe<T>
extends Object
implements Pipe<T>
    A no-op pipe with only one side effect - progress tracking. Progress in the input pipe is tracked by a callback method being called each time there's a progress in at least 1%.
    Author:
    Eyal Schneider

    • Constructor Detail

      • ProgressPipe

        public ProgressPipe​(Pipe<T> input,
                    int sampleRate,
                    Consumer<Integer> callback)
        Constructor
        Parameters:
        input - The input pipe
        sampleRate - For reducing computation overhead, The progress is being checked only every sampleRate items.
        callback - The callback to be called with the new progress percentage when an increase is noticed. The callback will be called only for unique integer percentage values, so it will be called at most 101 times (0-100).

    • Method Detail

      • next

        public T next()
       throws PipeException,
              InterruptedException
        Specified by:
        next in interface Pipe<T>
        Returns:
        The next item in this pipe output, or null if the output end has been reached. May be a blocking operation.
        Throws:
        PipeException - In case of pipe errors in this pipe or somewhere up-stream while trying to prepare next item to return.
        InterruptedException - In case that the operation has been interrupted by another thread.

      • peek

        public T peek()
        Specified by:
        peek in interface Pipe<T>
        Returns:
        The next item in the pipe's output. Does not remove it, so next call to next() will return it.

      • start

        public void start()
           throws PipeException,
                  InterruptedException
        Description copied from interface: BasePipe
        Performs pre-processing prior to item flow throw the pipe. Implementations must call the same method for all their input pipes before accessing their items. This is typically done here.
        Specified by:
        start in interface BasePipe
        Throws:
        PipeException - In case of pipe errors in this pipe or somewhere up-stream.
        InterruptedException - In case that the operation has been interrupted by another thread.

      • getProgress

        public float getProgress()
        Specified by:
        getProgress in interface BasePipe
        Returns:
        The pipe flow progress, as a floating number between 0.0 and 1.0. Important implementation rules: 1) Calling this method before start() call is complete isn't allowed and has an undefined behavior. 2) Implementation should do best effort to provide an estimate of the progress this pipe has made (0.0 - 1.0) 3) When the pipe is fully consumed, getProgress() should return 1.0. 4) Results must be monotonous, i.e. results of consecutive calls may never be decreasing. 5) Thread safety: progress may be maintained by some thread/s but monitoring by other threads. Implementations must be thread safe.