Implementation of Boyer Moore Horsepool algorithm with wildcards

Question

I want to implement a generalization of the Boyer Moore Horspool algorithm that takes care of wildcards (match any letter in the word). This means that the pattern h _ _ s e would be found two times in this text: horsehouse.

I need help to implement this, I cant get deep enough understanding of the algorithm to figure this out by myself, some tips ?

int [] createBadCharacterTable(char [] needle) {

        int [] badShift = new int [256];

        for(int i = 0; i < 256; i++) {
            badShift[i] = needle.length;
        }

        int last = needle.length - 1;

        for(int i = 0; i < last; i++) {
            badShift[(int) needle[i]] = last - i;
        }

        return badShift;
    }

    int boyerMooreHorsepool(String word, String text) {

        char [] needle = word.toCharArray();
        char [] haystack = text.toCharArray();

        if(needle.length > haystack.length) {
            return -1;
        }

        int [] badShift = createBadCharacterTable(needle);

        int offset = 0;
        int scan = 0;
        int last = needle.length - 1;   
        int maxoffset = haystack.length - needle.length;

        while(offset <= maxoffset) {
            for(scan = last; (needle[scan] == haystack[scan+offset] ||  needle[scan] == (int) '_'); scan--) {

                if(scan == 0) { //Match found
                    return offset;
                }
            }
            offset += badShift[(int) haystack[offset + last]];
        }
        return -1;
    }