How to use

bitCount

method

in

javolution.lang.MathLib

@Override
public int cardinality() {
  int sum = 0;
  for (int i = 0; i < bits.length; i++) {
    sum += MathLib.bitCount(bits[i]);
  }
  return sum;
}

/**
 * Returns the number of bits set to {@code true} (or the size of this 
 * set).
 *
 * @return the number of bits being set.
 */
public int cardinality() {
  int sum = 0;
  for (int i = 0; i < _length; i++) {
    sum += MathLib.bitCount(bits[i]);
  }
  return sum;
}

public  Index  valueOf(Record record) {
  int i = ((Index)record).intValue();
  int count= 0;
  for (int j = 0; j < _length;) {
    long l = bits[j++];
    count += MathLib.bitCount(l);
    if (count > i) { // Found word for record.
      int bitIndex = j << 6;
      while (count != i) {
        int shiftRight = MathLib.numberOfLeadingZeros(l) + 1;
        l <<= shiftRight;
        bitIndex -= shiftRight;
        count--;
      }
      return Index.valueOf(bitIndex);
    }
  }
  return null;
}