Change update DataPoints by a subscription way

src/main/java/ch/hevs/isi/core/DataPoint.java

@@ -22,9 +22,9 @@ public abstract class DataPoint{
         } else {
             dataPointMap.replace(this.label, this);
         }
-        DatabaseConnector.getMySelf().onNewValue(this);
-        WebConnector.getMySelf().onNewValue(this);
-        FieldConnector.getMySelf().onNewValue(this);
+
+        // Update every connector
+        DataPointListener.listeners.forEach(listener -> listener.onNewValue(this));
     }
     public static DataPoint getDataPointFromLabel(String label){
         if( !dataPointMap.containsKey(label) ){

src/main/java/ch/hevs/isi/core/DataPointListener.java

@@ -1,6 +1,20 @@
 package ch.hevs.isi.core;
 
+import java.util.Vector;
+
 public interface DataPointListener {
 
+    // Vector of listeners
+    Vector<DataPointListener> listeners = new Vector<>();
+
     void onNewValue(DataPoint dp);
+
+    /**
+     * Subscribe to the update of the DataPoint
+     * @param listener the listener to subscribe
+     */
+    static void subscribeUpdate(DataPointListener listener){
+        // Call by final class for subscribe update
+        listeners.add(listener);
+    }
 }

src/main/java/ch/hevs/isi/db/DatabaseConnector.java

@@ -56,6 +56,9 @@ public class DatabaseConnector implements DataPointListener {
         if (bucket == null){
             bucket = properties.getProperty("BUCKET");
         }
+
+        // Subscribe to the update of DataPoints
+        DataPointListener.subscribeUpdate(this);
     }
 
     /**

src/main/java/ch/hevs/isi/field/FieldConnector.java

@@ -10,6 +10,8 @@ public class FieldConnector implements DataPointListener {
 
     private FieldConnector(){
 
+        // Subscribe to the update of DataPoints
+        DataPointListener.subscribeUpdate(this);
     }
 
     public static FieldConnector getMySelf(){

src/main/java/ch/hevs/isi/web/WebConnector.java

@@ -8,6 +8,8 @@ public class WebConnector implements DataPointListener {
 
     private WebConnector (){
 
+        // Subscribe to the update of DataPoints
+        DataPointListener.subscribeUpdate(this);
     }
 
     public static WebConnector  getMySelf(){