Package org.apache.lucene.util

Class OpenBitSetIterator

  • public class OpenBitSetIterator
extends DocIdSetIterator
    An iterator to iterate over set bits in an OpenBitSet. This is faster than nextSetBit() for iterating over the complete set of bits, especially when the density of the bits set is high.

    • Field Detail

      • bitlist

        protected static final int[] bitlist

    • Constructor Detail

      • OpenBitSetIterator

        public OpenBitSetIterator​(OpenBitSet obs)

      • OpenBitSetIterator

        public OpenBitSetIterator​(long[] bits,
                          int numWords)

    • Method Detail

      • nextDoc

        public int nextDoc()
        alternate shift implementations // 32 bit shifts, but a long shift needed at the end private void shift2() { int y = (int)word; if (y==0) {wordShift +=32; y = (int)(word >>>32); } if ((y & 0x0000FFFF) == 0) { wordShift +=16; y>>>=16; } if ((y & 0x000000FF) == 0) { wordShift +=8; y>>>=8; } indexArray = bitlist[y & 0xff]; word >>>= (wordShift +1); } private void shift3() { int lower = (int)word; int lowByte = lower & 0xff; if (lowByte != 0) { indexArray=bitlist[lowByte]; return; } shift(); }
        Specified by:
        nextDoc in class DocIdSetIterator

      • advance

        public int advance​(int target)
        Description copied from class: DocIdSetIterator
        Advances to the first beyond (see NOTE below) the current whose document number is greater than or equal to target. Returns the current document number or DocIdSetIterator.NO_MORE_DOCS if there are no more docs in the set.

        Behaves as if written: 

         int advance(int target) {
   int doc;
   while ((doc = nextDoc()) < target) {
   }
   return doc;
 }
        Some implementations are considerably more efficient than that.

        NOTE: when target ≤ current implementations may opt not to advance beyond their current DocIdSetIterator.docID().

        NOTE: this method may be called with DocIdSetIterator.NO_MORE_DOCS for efficiency by some Scorers. If your implementation cannot efficiently determine that it should exhaust, it is recommended that you check for that value in each call to this method.

        NOTE: after the iterator has exhausted you should not call this method, as it may result in unpredicted behavior.

        Specified by:
        advance in class DocIdSetIterator