Technotrance, Illusions and Perspectives

Yahoo Map services expose REST web-services API which aid the consumer to retreive maps given a locations based on address (street, city, state or zip) or coordinates (longitude, latitude). This cool tip explores an option to render a Yahoo hosted map for a PrimeFaces driven application.

1) Login to Yahoo Developer Network and generate an Yahoo Developer Application ID.

2) Define and implement a PrimeFaces Controller which defines a MapMetadata POJO (containing address based attributes or coordinate based attributes) and defines a method to render the map accordingly.

@Controller(name = "mapController", scope = REQUEST)
public class YahooMapController
{   private String mapURL = new String();
    private boolean showMap = false;
    private MapMetadata map = new MapMetadata();
    //setters and accessors
    public void renderMapByAddress()
    {   StringBuilder query = new StringBuilder();
        String details = map.getStreet();
        query.append((details!=null)?"street=" + details + "&":"");
        details = map.getCity();

        query.append((details!=null)?"city=" + details + "&":"");
        details = map.getState();

        query.append((details!=null)?"state=" + details + "&":"");
        details = map.getZip();

        query.append((details!=null)?"zip=" + details + "&":"");
        details = map.getLatitude();

        query.append((details1!=null)?"latitude=" + details1 + "&":"");
        details = map.getLongitude();

        query.append((details!=null)?"longitude=" + details + "&":"");
       renderMap(query.toString());
    }

    private void renderMap(String query)
    {   if (query.length() > 0)
        {   try {
                query = query.replace(" ", "+");
                String requestquery = "http://local.yahooapis.com/MapsService/V1/mapImage?appid=[my-app-id]" + query;
                HttpClient client = new HttpClient();
                GetMethod method = new GetMethod(requestquery);
                int statusCode = client.executeMethod(method);
                if (statusCode != HttpStatus.SC_OK)
                {   FacesContext.getCurrentInstance().addMessage(null, new FacesMessage(FacesMessage.SEVERTY_ERROR, "Unable to find map based on details!", "Unable to find map based on details!"));
                    showMap = false;
                    return;
                }
                InputStream rstream = method.getResponseBodyAsStream();
                BufferedReader br = new BufferedReader(new InputStreamReader(rstream));
		String line;
		int i = 0;
		while ((line = br.readLine()) != null)
                {   if (i == 1 && line.contains("Result"))
                    {   mapURL = line.substring(62, line.length() - 9);
                        showMap = true;
                    }
                    i++;
		}
            } catch (IOException ex)
            {   ex.printStackTrace();
            }
        }
    }
}

The REST Get request is being placed using the Apache Commons HTTPClient library. The response from REST Get call is striped to fetch only the URL which displays the actual image of the Map.

3) Define and implement a XHTML page which defines a the view for accepting the location details and a rendering panel which is displayed if the map is successfully retrieved.

<ui:define name="content">
    <h:form>
        <h:messages/>
        <p:panel header="View Map">
          <h:panelGrid columns="2">
             <h:outputLabel value="Street :" for="street"></h:outputLabel>
             <h:inputText id="street" value="#{mapController.map.street}"/>

             <!-- Other input fields with labels accordingly -->

            <h:panelGroup>
             <h:commandButton action="#{mapController.renderMapByAddress}" value="Show Map" />
            </h:panelGroup>
          </h:panelGrid>
        </p:panel>
        <p:panel header="Map" rendered="#{mapController.showMap}">
           <h:panelGrid columns="1">
              <h:graphicImage value="#{mapController.mapURL}"/>
           </h:panelGrid>
        </p:panel>
     </h:form>
 </ui:define>

The graphicImage from JSF HTML taglib displays the URL generated image. One can also use the PrimeFaces dynamicImage Streaming (with StreamedContent)