code: public void concat(Value value) {
  	if (concatValue != null) {
  	    concatValue.concat(value);
  	} else {
  	    concatValue = value;
  	}
      }
docs: Appends the specified value to the end of the chain
  of concatinated values. That is, if this value has
  no concatinated value then set the specified value
  as the concatinated value. If this value already
  has a concatinated value then append the
  specified value to that concatinated value.
  
  @param value the value to concatinate.