Validator.java

val.addConstraint(phone, new Constraint() {
  public  boolean isValid(Object value) {
    String v = (String)value;
    for(int i = 0 ; i < v.length() ; i++) {
      char c = v.charAt(i);
      if(c >= '0' && c <= '9' || c == '+' || c == '-') {
        continue;
      }
      return false;
    }
    return true;
  }
  public String getDefaultFailMessage() {
    return "Must be valid phone number";
  }
});