Class MaskedIntIterator

  • All Implemented Interfaces:
    LazyIntIterator

    public class MaskedIntIterator
    extends java.lang.Object
    implements LazyIntIterator
    An iterator returning the element of an underlying iterator but filters them using a inclusion-exclusion block list.

    A mask is an array of integers. The sum of the values contained in the mask must not exceed the number of elements returned by the underlying iterator. Moreover, all integers in the mask must be positive, except possibly for the first one, which may be zero.

    Mask values are interpreted as specifying inclusion-exclusion blocks. Suppose that the underlying iterator returns N values, and that the mask is n0, n1, …, nk. Then, the first n0 values returned by the underlying iterator must be kept, the next n1 values must be ignored, the next n2 must be kept and so on. The last N−(n0+…+nk) must be kept if k is odd, and must be ignored otherwise. An instance of this class will returns the kept values only, in increasing order.

    • Constructor Summary

      Constructors 
      Constructor Description
      MaskedIntIterator​(int[] mask, int maskLen, LazyIntIterator underlying)
      Creates a new masked iterator using a given mask, mask length and underlying iterator.
      MaskedIntIterator​(int[] mask, LazyIntIterator underlying)
      Creates a new masked iterator using a given mask and underlying iterator.
    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      int nextInt()
      The next integer returned by this iterator, or the special marker if this iterator is exhausted.
      int skip​(int n)
      Skips a given number of elements.
      • Methods inherited from class java.lang.Object

        clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
    • Constructor Detail

      • MaskedIntIterator

        public MaskedIntIterator​(int[] mask,
                                 LazyIntIterator underlying)
        Creates a new masked iterator using a given mask and underlying iterator.
        Parameters:
        mask - a mask, or null, meaning an empty mask (everything is copied).
        underlying - an underlying iterator.
      • MaskedIntIterator

        public MaskedIntIterator​(int[] mask,
                                 int maskLen,
                                 LazyIntIterator underlying)
        Creates a new masked iterator using a given mask, mask length and underlying iterator.
        Parameters:
        mask - a mask, or null, meaning an empty mask (everything is copied).
        maskLen - an explicit mask length.
        underlying - an underlying iterator.
    • Method Detail

      • nextInt

        public int nextInt()
        Description copied from interface: LazyIntIterator
        The next integer returned by this iterator, or the special marker if this iterator is exhausted.
        Specified by:
        nextInt in interface LazyIntIterator
        Returns:
        next integer returned by this iterator, or the special marker if this iterator is exhausted.
      • skip

        public int skip​(int n)
        Description copied from interface: LazyIntIterator
        Skips a given number of elements.
        Specified by:
        skip in interface LazyIntIterator
        Parameters:
        n - the number of elements to skip.
        Returns:
        the number of elements actually skipped (which might be less than n if this iterator is exhausted).