code: public static int getCDSLengthForward(List<Integer> exonStarts, List<Integer> exonEnds, int cdsStart, int cdsEnd) {
  
  		int codingLength = 0;
  
  		for (int i = 0; i < exonStarts.size(); i++) {
  
  			int start = exonStarts.get(i)+base;
  			int end = exonEnds.get(i);
  
  			if ( (start < cdsStart+base && end < cdsStart) || (start > cdsEnd && end > cdsEnd) )
  				continue;
  
  			if (start < cdsStart+base)
  				start = cdsStart+base;
  
  			if (end > cdsEnd)
  				end = cdsEnd;
  
  			codingLength += (end - start + 1);
  		}
  		return codingLength-3 ;
  	}
docs: Get the length of the coding sequence
  
  @param exonStarts
  @param exonEnds
  @param cdsStart
  @param cdsEnd
  @return