Web GIS

ThreadPoolExecutor (embedded in TaskManager) 管理threads的新增回收

• setCorePoolSize - available 
• setMaximumPoolSize - max (2 x available)
• setKeepAliveTime  - 10 secods (TimeUnit.SECONDS) - when thread number exceeding max, the idle ones are collected 
• setRejectedExecutionHandler - 當workQueue滿了，池中的執行緒數又達到了maximumPoolSize，這個時候已經沒有多餘的資源處理請求了，需要RejectedExecutionHandler 來處理。
• execute - 執行command

WebGISListener 做為一個listener, 多了兩個聽到了要做的函式動作

void onRegisterForItinerary(RegisterForItinerary data);
void onGetItineraries(GetItineraryResult data); 

                MainActivity 在此成為一位WebGISListener 

WebGISResponse 做為一個等待WEB動作的守門人，一旦結束動作立刻回報

public void addListener(WebGISListener listener)
public void removeListener(WebGISListener listener)
public abstract void notifyListeners();  

abstract void parseJSON(JsonReader reader) 

1. public class GetItineraryResult extends WebGISResponse 

    - 負責取得網傳的itn
2. public class RegisterForItinerary extends WebGISResponse
    - 負責註冊新的ID上到網址

以上兩者均各自override parseJSON與notifyListener的部分

GetItineraryResults在notifyListener處呼叫了onGetItineraries

而RegisterForItinerary在notifyListener處則呼叫了onRegisterForItinerary

public class WebGISClient {

    public static final String TAG = "WebGISClient";
    private static final String webgisUrl = "https://mapi.polstarapis.com/";

}

public static Runnable get(String uri, WebGISResponse result)
HttpsURLConnection conn = (HttpsURLConnection) url.openConnection();
conn.setRequestMethod("GET");

public static Runnable post(String uri, HashMap<String, String> params, WebGISResponse result)

HttpsURLConnection conn = (HttpsURLConnection) url.openConnection();
conn.setRequestMethod("POST");

WebGISClient 擔任interface角色提供MainActivity需要時建立的runnable
runnable透過TaskManager帶入執行，WebGISResponse帶入等結果，
一收到就NotifyListener，回傳給MainActivity做處理 :

private static void RequestItinerary() {
   GetItineraryResult result = new GetItineraryResult();
   Runnable r = WebGISClient.get("itinerary/api/getItinerary/" + SN, result);
   result.addListener(MainActivity.mSingleton);
   mTaskManager.execute(r);
}
private static void UploadUserIdForItinerary(String userid) {
   HashMap<String, String> params = new HashMap<>();
   params.put("serialNo", SN);
   params.put("label", userid);
   RegisterForItinerary result = new RegisterForItinerary();
   Runnable r = WebGISClient.post("itinerary/api/register", params, result);
   mTaskManager.execute(r);
}
public void onGetItineraries(GetItineraryResult data) {
   String toStr = String.format(Locale.getDefault(), "status=%d, message=%s", data.status, data.message);
   if (data.status == -1) {
      return;
   }
   int len = 0, i = 0;
   for (ItineraryEntry e : data.itineraries) len++;
   String[] titles = new String[len];
   String[] subTitles = new String[len];
   double[] longitudes = new double[len];
   double[] latitudes = new double[len];
   double[] navLongitudes = new double[len];
   double[] navLatitudes = new double[len];
   for (ItineraryEntry e : data.itineraries) {
      titles[i] = e.title;
      subTitles[i] = e.subTitle;
      longitudes[i] = e.longitude;
      latitudes[i] = e.longitude;
      navLongitudes[i] = e.navLongitude;
      navLatitudes[i] = e.navLatitude;
      i++;
   }
   MainActivity.nativeSetItineraries(data.itineraryName, titles, subTitles, longitudes, latitudes, navLongitudes, navLatitudes);
}
HTTPUrlConnection 可用的methods :
Set the method for the URL request, one of:
GET (用到)
POST (用到)
HEAD
OPTIONS
PUT
DELETE
TRACE
are legal, subject to protocol restrictions. The default method is GET.