Changing Sort Order

[JoeOCLC]

We are displaying a list of objects in a JSP window and sorting it using the stardard Arrays.sort with a specialized comparator to sort on just one string within the object. Our product managers aren't happy with the standard lexicographic sorting that java uses. They want the special characters (~, !, @, etc) to appear at the head of the list instead of the tail.

Are there any suggestions on easy ways to write the comparator for this?

--

Joe Nelson
OCLC Online Computer Library Center, Inc.
Dublin, OH

 

[byam]

This code should do it:

String[] list = { "asadfdsf", "@aaadfdsf", "!safdsf" };
Arrays.sort(list, 
            new Comparator() {
              public int compare(Object arg0, Object arg1) {
                  return ((String)arg0).compareTo(arg1);
              }
            }
           );

 

[JoeOCLC]

This only partially works. Try putting an underscore "_" or a tilde "~" at the start of the string.

It sorts by ASCII code, and there are special characters "out of order" in ASCII.

--

Joe Nelson
OCLC Online Computer Library Center, Inc.
Dublin, OH

 

[byam]

ok. you will have to spec out all those special characters. Assuming you only interested in ASCII characters, then you can have a function to replace to special characters in the string before compare them. example:

public String replaceSpecialChar(String s) {
  StringBuffer sb = new StringBuffer();
  for (int i=0; i<s.length(); i++) {
    char charVar = s.charAt(i);
    switch (charVar) {
      case '[': charVar = (char)0; break; 
      case '\\': charVar = (char)1; break; 
      case ']': charVar = (char)2; break; 
      case '^': charVar = (char)3; break; 
      case '_': charVar = (char)4; break; 
      case (char)140: charVar = (char)5; break;
      case '{': charVar = (char)6; break;
      case '|': charVar = (char)7; break;
      case '}': charVar = (char)8; break;
      case '~': charVar = (char)9; break;
    }
    sb.append(charVar);
  }
  return sb.toString();
}

String[] list = { "asadfdsf", "@aaadfdsf", 
                  "!safdsf", "[sdfdsaf", 
                  "bbbb", "_asfdfadsf"};
Arrays.sort(list, new Comparator() {
  public int compare(Object arg0, Object arg1) {
    String a = replaceSpecialChar((String)arg0);
    String b = replaceSpecialChar((String)arg1);
    return (a.compareTo(b));
  }
});

 

[JoeOCLC]

Right, I've found an easier way by simply checking to see if its a digit, char or otherwise.

Thanks anyway...

--

Joe Nelson
OCLC Online Computer Library Center, Inc.
Dublin, OH