code: public static CallerID buildFromComponents(final String firstname, final String lastname, final String number)
      {
          String name = ""; //$NON-NLS-1$
          if (firstname != null)
          {
              name += firstname.trim();
          }
  
          if (lastname != null)
          {
              if (name.length() > 0)
              {
                  name += " "; //$NON-NLS-1$
              }
              name += lastname.trim();
          }
  
          return PBXFactory.getActivePBX().buildCallerID(number, name);
      }
docs: This is a little helper class which will buid the name component of a
  clid from the first and lastnames. If both firstname and lastname are
  null then the name component will be an empty string.
  
  @param firstname the person's firstname, may be null.
  @param lastname the person's lastname, may be null
  @param number the phone number.
  @return