Package uk.ac.starlink.ttools.plot2.layer

Class AdaptiveBinList

  • All Implemented Interfaces:
    BinList
    public class AdaptiveBinList
extends java.lang.Object
implements BinList
    BinList implementation that starts off using a hash-based implementation, but switches to an array-based implementation if the hash gets full enough to make it worth while.
    Since:
    15 Jan 2019
    Author:
    Mark Taylor

    • Nested Class Summary

      • Nested classes/interfaces inherited from interface uk.ac.starlink.ttools.plot2.layer.BinList

        BinList.Result

    • Constructor Summary

      Constructors 
      Constructor Description
      AdaptiveBinList​(int size, Combiner combiner, int factThresh)
      Constructor.

    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      BinList getBaseBinList()
      Returns the bin list to which this one is currently delegating its operations.
      Combiner.Container getBinContainer​(long index)
      Returns a container representing the current contents of a given bin.
      Combiner getCombiner()
      Returns the combination method used for bins.
      BinList.Result getResult()
      Returns an object containing the result values accumulated into the bins so far.
      long getSize()
      Returns the maximum number of bins.
      boolean isHash()
      Indicates which underlying BinList implementation is currently in use.
      void submitToBin​(long index, double datum)
      Adds a given numeric value to the bin at the given index.

      • Methods inherited from class java.lang.Object

        clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

    • Constructor Detail

      • AdaptiveBinList

        public AdaptiveBinList​(int size,
                       Combiner combiner,
                       int factThresh)
        Constructor. The factThresh tuning parameter should be set to a value close to the ratio of HashBinList bin size to ArrayBinList bin size (in terms of storage). Object overhead is typically 2 words (16 bytes), so if the array has one double per bin and the hash has one (Long,Combiner.Container) pair per bin, the ratio will be at least 6.
        Parameters:
        size - maximum number of bins
        combiner - combiner
        factThresh - thershold factor - once size/factThresh bins are occupied, an array will be used instead

    • Method Detail

      • getCombiner

        public Combiner getCombiner()
        Description copied from interface: BinList
        Returns the combination method used for bins.
        Specified by:
        getCombiner in interface BinList
        Returns:
        combiner

      • getSize

        public long getSize()
        Description copied from interface: BinList
        Returns the maximum number of bins. All bins have an index in the range 0..size-1.
        Specified by:
        getSize in interface BinList
        Returns:
        bin count

      • submitToBin

        public void submitToBin​(long index,
                        double datum)
        Description copied from interface: BinList
        Adds a given numeric value to the bin at the given index. In general, NaN values should not be submitted.
        Specified by:
        submitToBin in interface BinList
        Parameters:
        index - bin index
        datum - finite value to submit to the bin

      • getBinContainer

        public Combiner.Container getBinContainer​(long index)
        Description copied from interface: BinList
        Returns a container representing the current contents of a given bin. This is only intended for reading; the effect of submitting additional data to the returned container is not defined.

        This method is here to support conversion between different BinList implementations.

        Specified by:
        getBinContainer in interface BinList
        Parameters:
        index - bin index
        Returns:
        container instance reporting the current state of the bin; may be null if the bin is not populated

      • getResult

        public BinList.Result getResult()
        Description copied from interface: BinList
        Returns an object containing the result values accumulated into the bins so far.

        It is up to implementations to decide how to implement this method. In some cases the return value may be an adapter that extracts results as required from the data structure used for value accumulation, but in others it may return a new data structure which copies the accumulated values to a more compact form up front. Therefore this may or may not be an expensive method, and the return value may or may not be affected by subsequent BinList.submitToBin(long, double) calls.

        Specified by:
        getResult in interface BinList
        Returns:
        accumulated bin values

      • getBaseBinList

        public BinList getBaseBinList()
        Returns the bin list to which this one is currently delegating its operations.
        Returns:
        base bin list

      • isHash

        public boolean isHash()
        Indicates which underlying BinList implementation is currently in use. It starts off true at object construction time, but may turn false if enough data are submitted. It will never change back again.
        Returns:
        true if underlying bin list is hash-based, false if it's array-based