Building a mashup service using messaging, maps and location

    public void pollingLoop ()
    {
        while (true)
        {
            try
            {
                SMSRequestObject smsRequest = getIncomingSMS();
                handleSMSRequest(smsRequest);
                //Adjust sleep time according to the SLA agreed with the operator.
                Thread.sleep (15*1000);
            }
            catch (Throwable th)
            {
                //TODO Add appropriate Exception handling
                logger.warning("Caught unhandled Throwable " + th);
            }
        }
    }

    public void handleSMSRequest (SMSRequestObject smsRequest)
    {
        //Get the location of the device based on the MSISDN
        LocationInfo li = getLocation(smsRequest.getSender());        
        
        if (li == null)
        {
            return; //TODO Handle customer interaction
        }
        
        //Get the URL to the generated map from Yahoo!Maps
        URL mapURL = getMapImageURL(li, 300, 300, 4);
        
        if (mapURL != null)
        {
            //The sender of the SMS request will be the recipient of the MMS.
            String[] recipients = new String[1];
            recipients[0] = smsRequest.getSender();
            try
            {
                //Download the image based on the found URL, 
                // using standard Java toolkit. 
                Image mapImage = Toolkit.getDefaultToolkit().getImage(mapURL);

                //sendMMS(recipients, mapImage, null);
            }
            catch (Throwable th)
            {
                //TODO Add appropriate Exception handling
                logger.warning("Caught unhandled Throwable " + th);
            }
        }
    }

    /**
     * Retrieves an URL pointing to a Yahoo Map.
     * See http://developer.yahoo.com/maps/
     * for further details on the Yahoo!Maps service API.
     * @param li the object containing longitude and lattitude values.
     * @param zoom The zoom level for the map, 
     *     from 1 (street level) to 12 (country level)
     * @param imgWidt width of the map image
     * @param imgHeight height of the map image
     * @return the URL to a map image generated by Yahoo!Maps. 
     *     Returns null if an error occured.
     */
    public URL getMapImageURL (LocationInfo li, int imgWidt, int imgHeight, int zoom)
    {
        //STEP 1: generate the URL to request Yahoo!Maps to generate a map image.
        
        //Sign up at Yahoo!Developer to retrieve your 
        //Yahoo application ID. http://developer.yahoo.com/
        StringBuffer urlBuffer = new StringBuffer ();
        urlBuffer.append ("http://local.yahooapis.com/MapsService/V1/mapImage");
        urlBuffer.append ("?appid="+yahooId);
        urlBuffer.append ("&latitude="+li.getLatitude());
        urlBuffer.append ("&longitude="+li.getLongitude());
        urlBuffer.append ("&zoom="+zoom);
        urlBuffer.append ("&image_width="+imgWidt);
        urlBuffer.append ("&image_height="+imgHeight);
        try
        {
            //STEP 2: Ask for an URL pointing to the map image. 

            //The URL for requesting the map generation.
            URL mapRequestURL = new URL(urlBuffer.toString());
            
            //Send the request to the Yahoo!Maps and 
            //read the response using an InputStream.
            Object contentObj = mapRequestURL.getContent();
            if (contentObj instanceof InputStream)
            {
                //Read the response XML from Yahoo!Maps
                InputStream in = (InputStream)contentObj;
                StringBuffer mapResponse = new StringBuffer();
                int r = in.read();
                while (r >= 0)
                {
                    mapResponse.append((char)r);
                    r = in.read();
                }
                in.close();
                
                //Using XPath to get the URL to the map image from the XML text
                XPath xpath = XPathFactory.newInstance().newXPath();
                String expression = "/Result/text()";
                ByteArrayInputStream bin = 
                    new ByteArrayInputStream(mapResponse.toString().getBytes());
                String result =  xpath.evaluate(expression, new InputSource(bin));
                bin.close();
                return new URL(result);
            }
            else
            {
                //TODO Add appropriate Exception handling
                logger.info ("Unexpected result when requesting a InputStream to " +
                    "read map URL. Expected InputStream, got: "+ contentObj.getClass());
                return null;
            }
        }
        catch (Throwable th)
        {
            //TODO Add appropriate Exception handling
            logger.warning("Caught unhandled Throwable " + th);
            return null;
        }
    }

    public class SMSRequestObject
    {
        private String message;
        private String sender;
        private String recipient;
        private long timestamp;
    }