Need Help With Project

I am doing a project that converts a string into morse code. I have most of it down except for that fact that I cannot get it to keep repeating so I tried inserting another while loop in the main method but i keep getting errors with my code and I need to insert a | in between each space but I have been unable to do that either. The following is my code so far if anyone has any tips I would greatly appreciate it.

Code :

---

import java.util.*;
 
 
public class MorseCodeProj
{
  public String Conversion(String s1){
    String result = "";
    StringTokenizer tokens = new StringTokenizer(s1);
    while(tokens.hasMoreTokens()){  
     String word = tokens.nextToken();
    for (int i = 0; i < word.length(); i++){
        switch(word.charAt(i)){
            case 'A':
            case 'a':
                result+=".-";
                break;
            case 'B':
            case 'b':
                result+="-...";
                break;
            case 'C':
            case 'c':
                result+="-.-.";
                break;
            case 'D':
            case 'd':
                result+="-..";
                break;
            case 'E':
            case 'e':
                result+=".";
                break;
            case 'F':
            case 'f':
                result+="..-.";
                break;
            case 'G':
            case 'g':
                result+="--.";
                break;
            case 'H':
            case 'h':
                result+="....";
                break;
            case 'I':
            case 'i':
                result+="..";
                break;
            case 'J':
            case 'j':
                result+=".---";
                break;
            case 'K':
            case 'k':
                result+="-.-";
                break;
            case 'L':
            case 'l':
                result+=".-..";
                break;
            case 'M':
            case 'm':
                result+="--";
                break;
            case 'N':
            case 'n':
                result+="-.";
                break;
            case 'O':
            case 'o':
                result+="---";
                break;
            case 'P':
            case 'p':
                result+=".--.";
                break;
            case 'Q':
            case 'q':
                result+="--.-";
                break;
            case 'R':
            case 'r':
                result+=".-.";
                break;
            case 'S':
            case 's':
                result+="...";
                break;
            case 'T':
            case 't':
                result+="-";
                break;
            case 'U':
            case 'u':
                result+="..-";
                break;
            case 'V':
            case 'v':
                result+="...-";
                break;
            case 'W':
            case 'w':
                result+=".--";
                break;
            case 'X':
            case 'x':
                result+="-..-";
                break;
            case 'Y':
            case 'y':
                result+="-.--";
                break;
            case 'Z':
            case 'z':
                result+="--..";
                break;
            case 1 : 
                result+=".----";
                break;
            case 2 :
                result+="..---";
                break;
            case 3 :
                result+="...--";
                break;
            case 4 :
                result+="....-";
                break;
            case 5 :
                result+=".....";
                break;
            case 6 :
                result+="-....";
                break;
            case 7 :
                result+="--...";
                break;
            case 8 :
                result+="---..";
                break;
            case 9 :
                result+="----.";
                break;
            case 0 :
                result+="-----";
                break;
 
 
    }
 
 
}
 
    }
    return result;
}
    public void mainMethod(){
    Scanner input = new Scanner(System.in);
    boolean DONE = true;
 
    while ( s1!equal(DONE)){
 
    System.out.println("Enter line of characters.");  
        String s1 = input.nextLine();
        System.out.println("Converted String : " + Conversion(s1));
 
    return false;
}
 
 
 
    }
 
}

---

I just edited my post incase you read it a few moments ago

Code :

---

import java.util.*;
 
 
public class MorseCodeProj
{
  public String Conversion(String s1){
    String result = "";
    StringTokenizer tokens = new StringTokenizer(s1);
    while(tokens.hasMoreTokens()){
     String word = tokens.nextToken();
    for (int i = 0; i < word.length(); i++){
        switch(word.charAt(i)){
            case 'A':
            case 'a':
                result+=".-";
                break;
            case 'B':
            case 'b':
                result+="-...";
                break;
            case 'C':
            case 'c':
                result+="-.-.";
                break;
            case 'D':
            case 'd':
                result+="-..";
                break;
            case 'E':
            case 'e':
                result+=".";
                break;
            case 'F':
            case 'f':
                result+="..-.";
                break;
            case 'G':
            case 'g':
                result+="--.";
                break;
            case 'H':
            case 'h':
                result+="....";
                break;
            case 'I':
            case 'i':
                result+="..";
                break;
            case 'J':
            case 'j':
                result+=".---";
                break;
            case 'K':
            case 'k':
                result+="-.-";
                break;
            case 'L':
            case 'l':
                result+=".-..";
                break;
            case 'M':
            case 'm':
                result+="--";
                break;
            case 'N':
            case 'n':
                result+="-.";
                break;
            case 'O':
            case 'o':
                result+="---";
                break;
            case 'P':
            case 'p':
                result+=".--.";
                break;
            case 'Q':
            case 'q':
                result+="--.-";
                break;
            case 'R':
            case 'r':
                result+=".-.";
                break;
            case 'S':
            case 's':
                result+="...";
                break;
            case 'T':
            case 't':
                result+="-";
                break;
            case 'U':
            case 'u':
                result+="..-";
                break;
            case 'V':
            case 'v':
                result+="...-";
                break;
            case 'W':
            case 'w':
                result+=".--";
                break;
            case 'X':
            case 'x':
                result+="-..-";
                break;
            case 'Y':
            case 'y':
                result+="-.--";
                break;
            case 'Z':
            case 'z':
                result+="--..";
                break;
            case 1 : 
                result+=".----";
                break;
            case 2 :
                result+="..---";
                break;
            case 3 :
                result+="...--";
                break;
            case 4 :
                result+="....-";
                break;
            case 5 :
                result+=".....";
                break;
            case 6 :
                result+="-....";
                break;
            case 7 :
                result+="--...";
                break;
            case 8 :
                result+="---..";
                break;
            case 9 :
                result+="----.";
                break;
            case 0 :
                result+="-----";
                break;
 
 
    }
 
[B]    if(tokens.hasMoreTokens())
    result += " ";[/B]
//I put a space there so it adds a space in case the statement entered is multiple words?
}
 
    }
    return result;
}
    public void mainMethod(){
    Scanner input = new Scanner(System.in);
 
// No boolean variable needed.
[B]    String s1;[/B]
    do{
        System.out.println("Enter line of characters.");  
        s1 = input.nextLine();
 
        if(!s1.equalsIgnoreCase("DONE"))
        System.out.println("Converted String : " + Conversion(s1));
        //the If statement is there so that we do not translate the word "done" when we exit.
 
//WHY did you have return true here?
    }while ( !s1.equalsIgnoreCase("DONE"));
//You cant test s1 before you even assigned it...replaced with do-while loop, now you can assign value to s1 BEFORE YOU TEST what it holds.
 
//the code now will continue asking for more till the word "done" is entered
 
 
 
    }
 
}

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As an aside from a quick glance at the code, you may want to consider using a StringBuilder or StringBuffer for more optimal performance. Relatively speaking String concatenation can be slow, and for longer strings this difference could be noticeable.