String link = "http://mdwhotel.appspot.com/api/v1/reservation/?res_id=";
link += reservationId + "&start=" + aDate + "&end=" + rDate + "&email=" + HR.getEmail();
Client client = Client.create();
WebResource webResource = client.resource(link);
webResource.accept("application/xml");
/*invoke the call*/
String resp = webResource.put(String.class);
/* if the application sends me back an XML who contains this message
* means that they don't have available rooms between thhose dates