Question

I working with this code

                   while((dictionaryWord = br_.readLine()) != null) 
            {
                if(dictionaryWord.matches("^"+word.replace("*" , "." )+"$"))
                {   
                    incrementCounter();
                    System.out.println(dictionaryWord);
                }
            }

Desired Goal: word = dgo

Output: dog, god, dogma megalogdon, etc….

Answer 1

You can build a Set<Character> of all the chars in word, and iterate it. If one character is not in dictionaryWord, then dictionaryWord does not fit. Only if all appear – print dictionaryWord

    String word = "dog";
    String  dictionaryWord;
    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    while((dictionaryWord = br.readLine()) != null)  {
        Set<Character> chars = new HashSet<Character>();
        for (char c : word.toCharArray()) {
            chars.add(c);
        }
        boolean match = true;
        for (Character c : chars) {
            String s = "" + c;
            if (!dictionaryWord.contains(s)) {
                match = false;
                break;
            }
        }
        if (match == true) 
            System.out.println(dictionaryWord);
    }

In the above code, the set creation can be moved out of the while loop, of course.

More efficient solution could be to create a Set from dictionaryWord as well, and then check if the intersection of the two sets is identical to the set representing word.

This will be:

    String word = "dog";
    Set<Character> set1 = new HashSet();
    for (char c : word.toCharArray()) {
        set1.add(c);
    }
    String  dictionaryWord;
    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    while((dictionaryWord = br.readLine()) != null)  {
        Set<Character> set2 = new HashSet();
        for (char c : dictionaryWord.toCharArray()) {
            set2.add(c);
        }           Set<String> intersection = new HashSet(CollectionUtils.intersection(set1, set2));
        if (set1.equals(intersection)) {
            System.out.println(dictionaryWord);
        } else System.out.println("bad");
    }

using CollectionUtils.intersection() from apache commons