@Test public void trim() { assertNull(Str.trim(null)); assertNull(Str.trim("")); assertNull(Str.trim(" ")); assertNull(Str.trim(" \t\n ")); assertNotNull(Str.trim(".")); assertNotNull(Str.trim(" . ")); }
public static String trim(String s) { if (s == null) return null; s = s.trim(); return s.length() > 0 ? s : null; }
Str { public static String trim(String s) { if (s == null) return null; s = s.trim(); return s.length() > 0 ? s : null; } }
Str { public static String trim(String s) { if (s == null) return null; s = s.trim(); return s.length() > 0 ? s : null; }  }
Str { public static String trim(String s) { if (s == null) return null; s = s.trim(); return s.length() > 0 ? s : null; }  static String trim(String s); static String group(String text, String regexp); static String group(String text, String regexp, int group); static Pair<String, String> groups(String text, String regexp, int group1, int group2); static boolean containsSpaces(String ... strings); static String lower(String s); static String upper(String s); }
Str { public static String trim(String s) { if (s == null) return null; s = s.trim(); return s.length() > 0 ? s : null; }  static String trim(String s); static String group(String text, String regexp); static String group(String text, String regexp, int group); static Pair<String, String> groups(String text, String regexp, int group1, int group2); static boolean containsSpaces(String ... strings); static String lower(String s); static String upper(String s);  }