share Igimi LiveDataConnection for equal combinations of device serial numbers

java/com.sap.sailing.domain.igtimiadapter.test/src/com/sap/sailing/domain/igtimiadapter/websocket/WebSocketTest.java

@@ -158,7 +158,7 @@ public class WebSocketTest {
         // the data from baur@stg-academy.org, particularly containing the Berlin test data
         Account account = igtimiConnectionFactory.registerAccountForWhichClientIsAuthorized("9fded995cf21c8ed91ddaec13b220e8d5e44c65808d22ec2b1b7c32261121f26");
         IgtimiConnection conn = igtimiConnectionFactory.connect(account);
-        LiveDataConnection liveDataConnection = conn.createLiveConnection(Collections.singleton("GA-EN-AAEJ"));
+        LiveDataConnection liveDataConnection = conn.getOrCreateLiveConnection(Collections.singleton("GA-EN-AAEJ"));
         liveDataConnection.addListener(new BulkFixReceiver() {
             @Override
             public void received(Iterable<Fix> fixes) {

java/com.sap.sailing.domain.igtimiadapter/src/com/sap/sailing/domain/igtimiadapter/IgtimiConnection.java

@@ -96,7 +96,7 @@ public interface IgtimiConnection {
      * 
      * @return a connection that the caller can use to stop the live feed by calling {@link LiveDataConnection#stop()}.
      */
-    LiveDataConnection createLiveConnection(Iterable<String> deviceSerialNumbers) throws Exception;
+    LiveDataConnection getOrCreateLiveConnection(Iterable<String> deviceSerialNumbers) throws Exception;
     
     /**
      * @param sessionIds

java/com.sap.sailing.domain.igtimiadapter/src/com/sap/sailing/domain/igtimiadapter/impl/IgtimiConnectionImpl.java

@@ -35,7 +35,8 @@ import com.sap.sailing.domain.igtimiadapter.User;
 import com.sap.sailing.domain.igtimiadapter.datatypes.Fix;
 import com.sap.sailing.domain.igtimiadapter.datatypes.Type;
 import com.sap.sailing.domain.igtimiadapter.shared.IgtimiWindReceiver;
-import com.sap.sailing.domain.igtimiadapter.websocket.WebSocketConnectionManager;
+import com.sap.sailing.domain.igtimiadapter.websocket.LiveDataConnectionFactory;
+import com.sap.sailing.domain.igtimiadapter.websocket.LiveDataConnectionFactoryImpl;
 import com.sap.sailing.domain.tracking.DynamicTrack;
 import com.sap.sailing.domain.tracking.DynamicTrackedRace;
 import com.sap.sailing.domain.tracking.TrackedRace;
@@ -45,10 +46,12 @@ public class IgtimiConnectionImpl implements IgtimiConnection {
     private static final Logger logger = Logger.getLogger(IgtimiConnectionImpl.class.getName());
     private final Account account;
     private final IgtimiConnectionFactoryImpl connectionFactory;
+    private final LiveDataConnectionFactory liveDataConnectionFactory;
     
     public IgtimiConnectionImpl(IgtimiConnectionFactoryImpl connectionFactory, Account account) {
         this.connectionFactory = connectionFactory;
         this.account = account;
+        liveDataConnectionFactory = new LiveDataConnectionFactoryImpl(connectionFactory, account);
     }
     
     @Override
@@ -184,8 +187,8 @@ public class IgtimiConnectionImpl implements IgtimiConnection {
     
 
     @Override
-    public LiveDataConnection createLiveConnection(Iterable<String> deviceSerialNumbers) throws Exception {
-        return new WebSocketConnectionManager(connectionFactory, deviceSerialNumbers, getAccount());
+    public LiveDataConnection getOrCreateLiveConnection(Iterable<String> deviceSerialNumbers) throws Exception {
+        return liveDataConnectionFactory.getOrCreateLiveDataConnection(deviceSerialNumbers);
     }
 
     private DynamicTrack<Fix> getOrCreateTrack(Map<String, Map<Type, DynamicTrack<Fix>>> result,

java/com.sap.sailing.domain.igtimiadapter/src/com/sap/sailing/domain/igtimiadapter/impl/IgtimiWindTracker.java

@@ -46,7 +46,7 @@ public class IgtimiWindTracker extends AbstractWindTracker implements WindTracke
                                 IgtimiConnection connection = connectionFactory.connect(account);
                                 Iterable<String> devicesWeShouldListenTo = connection.getWindDevices();
                                 if (!stopping) {
-                                    LiveDataConnection liveConnection = connection.createLiveConnection(devicesWeShouldListenTo);
+                                    LiveDataConnection liveConnection = connection.getOrCreateLiveConnection(devicesWeShouldListenTo);
                                     IgtimiWindReceiver windReceiver = new IgtimiWindReceiver(devicesWeShouldListenTo);
                                     liveConnection.addListener(windReceiver);
                                     windReceiver.addListener(new WindListenerSendingToTrackedRace(Collections.singleton(getTrackedRace()), windTrackerFactory));

java/com.sap.sailing.domain.igtimiadapter/src/com/sap/sailing/domain/igtimiadapter/websocket/LiveDataConnectionFactory.java

@@ -0,0 +1,16 @@
+package com.sap.sailing.domain.igtimiadapter.websocket;
+
+import com.sap.sailing.domain.igtimiadapter.LiveDataConnection;
+
+/**
+ * Helps bundling live data connections for the same set of devices. Clients can request a connection for a set of devices.
+ * If one already exists, a wrapper to it is returned. This wrapper's {@link LiveDataConnection#stop()} method work such that
+ * it only decrements a usage counter in this factory (and does so at most once), such that the actual connection is only
+ * terminated if the last client has stopped using it.
+ *  
+ * @author Axel Uhl (D043530)
+ *
+ */
+public interface LiveDataConnectionFactory {
+    LiveDataConnection getOrCreateLiveDataConnection(Iterable<String> deviceSerialNumbers) throws Exception;
+}

java/com.sap.sailing.domain.igtimiadapter/src/com/sap/sailing/domain/igtimiadapter/websocket/LiveDataConnectionFactoryImpl.java

@@ -0,0 +1,66 @@
+package com.sap.sailing.domain.igtimiadapter.websocket;
+
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.Map;
+import java.util.Set;
+import java.util.logging.Logger;
+
+import com.sap.sailing.domain.common.impl.Util;
+import com.sap.sailing.domain.igtimiadapter.Account;
+import com.sap.sailing.domain.igtimiadapter.LiveDataConnection;
+import com.sap.sailing.domain.igtimiadapter.impl.IgtimiConnectionFactoryImpl;
+
+public class LiveDataConnectionFactoryImpl implements LiveDataConnectionFactory {
+    private static final Logger logger = Logger.getLogger(LiveDataConnectionFactoryImpl.class.getName());
+    private final IgtimiConnectionFactoryImpl connectionFactory;
+    private final Account account;
+    private final Map<Set<String>, LiveDataConnection> dataConnectionsForDeviceSerialNumbers;
+    private final Map<LiveDataConnection, Set<String>> deviceSerialNumersForDataConnections;
+    private final Map<LiveDataConnection, Integer> usageCounts;
+
+    public LiveDataConnectionFactoryImpl(IgtimiConnectionFactoryImpl connectionFactory, Account account) {
+        this.connectionFactory = connectionFactory;
+        this.account = account;
+        dataConnectionsForDeviceSerialNumbers = new HashMap<>();
+        deviceSerialNumersForDataConnections = new HashMap<>();
+        usageCounts = new HashMap<>();
+    }
+    
+    @Override
+    public synchronized LiveDataConnection getOrCreateLiveDataConnection(Iterable<String> deviceSerialNumbers) throws Exception {
+        Set<String> deviceSerialNumbersAsSet = new HashSet<>();
+        Util.addAll(deviceSerialNumbers, deviceSerialNumbersAsSet);
+        LiveDataConnection result = dataConnectionsForDeviceSerialNumbers.get(dataConnectionsForDeviceSerialNumbers);
+        if (result == null) {
+            result = new WebSocketConnectionManager(connectionFactory, deviceSerialNumbers, account);
+            dataConnectionsForDeviceSerialNumbers.put(deviceSerialNumbersAsSet, result);
+            deviceSerialNumersForDataConnections.put(result, deviceSerialNumbersAsSet);
+        }
+        Integer usageCount = usageCounts.get(result);
+        if (usageCount == null) {
+            usageCount = 0;
+        }
+        usageCount++;
+        usageCounts.put(result, usageCount);
+        return result;
+    }
+
+    public synchronized void stop(LiveDataConnection actualConnection) throws Exception {
+        Integer usageCount = usageCounts.get(actualConnection);
+        if (usageCount == null || usageCount == 0) {
+            logger.warning("Strange: the Igtimi live data connection "+actualConnection+" is released by another client although no client should be using it anymore.");
+        } else {
+            usageCount--;
+            if (usageCount == 0) {
+                usageCounts.remove(actualConnection);
+                Set<String> deviceSerialNumbersAsSet = deviceSerialNumersForDataConnections.remove(actualConnection);
+                dataConnectionsForDeviceSerialNumbers.remove(deviceSerialNumbersAsSet);
+                actualConnection.stop();
+            } else {
+                usageCounts.put(actualConnection, usageCount);
+            }
+        }
+    }
+
+}

java/com.sap.sailing.domain.igtimiadapter/src/com/sap/sailing/domain/igtimiadapter/websocket/LiveDataConnectionWrapper.java

@@ -0,0 +1,37 @@
+package com.sap.sailing.domain.igtimiadapter.websocket;
+
+import com.sap.sailing.domain.igtimiadapter.BulkFixReceiver;
+import com.sap.sailing.domain.igtimiadapter.LiveDataConnection;
+
+public class LiveDataConnectionWrapper implements LiveDataConnection {
+    private final LiveDataConnectionFactoryImpl factory;
+    
+    private final LiveDataConnection actualConnection;
+    
+    private boolean stopCalled;
+    
+    protected LiveDataConnectionWrapper(LiveDataConnectionFactoryImpl factory, LiveDataConnection actualConnection) {
+        super();
+        this.factory = factory;
+        this.actualConnection = actualConnection;
+    }
+
+    @Override
+    public synchronized void stop() throws Exception {
+        if (!stopCalled) {
+            factory.stop(actualConnection);
+            stopCalled = true;
+        }
+    }
+
+    @Override
+    public boolean waitForConnection(long timeoutInMillis) throws InterruptedException {
+        return actualConnection.waitForConnection(timeoutInMillis);
+    }
+
+    @Override
+    public void addListener(BulkFixReceiver listener) {
+        actualConnection.addListener(listener);
+    }
+
+}

java/com.sap.sailing.server.gateway/src/com/sap/sailing/server/gateway/impl/WindStatusServlet.java

@@ -176,7 +176,7 @@ public class WindStatusServlet extends SailingServerHttpServlet {
             if (account.getUser() != null) {
                 IgtimiConnection igtimiConnection = igtimiConnectionFactory.connect(account);
                 try {
-                    LiveDataConnection liveDataConnection = igtimiConnection.createLiveConnection(igtimiConnection.getWindDevices());
+                    LiveDataConnection liveDataConnection = igtimiConnection.getOrCreateLiveConnection(igtimiConnection.getWindDevices());
                     result = true;
                     liveDataConnection.addListener(new BulkFixReceiver() {
                         @Override