Splitting the string, memorizing the delimiter and appending it as a space

Chaffy :

Good day everyone,

I have a string that looks like this (Morse code):

....x.x.-..x.-..x---xx...x-x.-x-.-.x-.-x---x...-x.x.-.x..-.x.-..x---x.--

single "x" means that the letter is finishing at that point, double "x" means that it's the end of the whole word. I have a map with Morse code. I am splitting the string by "x", then comparing each encoded letter to values in my dictionary and appending the matching key to my StringBuilder, it works correctly but I want to keep spaces between the words instead of double xx.

My piece of code:

private static final Map<Character, String> morseCode;
    static {
        morseCode = new HashMap<Character, String>();
        morseCode.put('h', "....");
        morseCode.put('e', ".");
        morseCode.put('l', ".-..");
        morseCode.put('o', "---");
        morseCode.put('s', "...");
        morseCode.put('t', "-");
        morseCode.put('a', ".-");
        morseCode.put('c', "-.-.");
        morseCode.put('k', "-.-");
        morseCode.put('v', "...-");
        morseCode.put('r', ".-.");
        morseCode.put('f', "..-.");
        morseCode.put('w', ".--");
    }

String decodedMorseTable = "....x.x.-..x.-..x---xx...x-x.-x-.-.x-.-x---x...-x.x.-.x..-.x.-..x---x.--"
StringBuilder decodedText = new StringBuilder();
String[] splitLetters = decodedMorseTable.split("x");
    for(String letter: splitLetters) {
        for(Map.Entry<Character, String> entry: morseCode.entrySet()) {
            if(entry.getValue().equals(letter))
                decodedText.append(entry.getKey());

Output:

hellostackoverflow

ETO :

Try splitting the input into separate words first (by xx). Then split each word as you did before:

String decodedMorseTable = "....x.x.-..x.-..x---xx...x-x.-x-.-.x-.-x---x...-x.x.-.x..-.x.-..x---x.--";
StringBuilder decodedText = new StringBuilder();
String[] words = decodedMorseTable.split("xx");
for (String word : words) {
    String[] splitLetters = word.split("x");
    for (String letter : splitLetters) {
        for (Map.Entry<Character, String> entry : morseCode.entrySet()) {
            if (entry.getValue().equals(letter))
                decodedText.append(entry.getKey());
        }
    }
    decodedText.append(" ");
 }

Update

If you modify your morseCode to have morse letters as keys and the characters as values then the code will look much simpler (avoiding 3rd loop):

private static final Map<String, Character> morseCode;
static {
    morseCode = new HashMap<>();
    morseCode.put("....", 'h');
    morseCode.put(".", 'e');
    morseCode.put("", ' ');
...   


String[] splitLetters = word.split("x");
for (String letter : splitLetters) {
    decodedText.append(morseCode.get(letter));
}

Java 1.8+ solution:

Arrays.stream(decodedMorseTable.split("x"))
      .map(morseCode::get)
      .forEach(decodedText::append);