1 files changed, 211 insertions, 0 deletions
diff --git a/src/org/traccar/web/AsyncServlet.java b/src/org/traccar/web/AsyncServlet.java
new file mode 100644
index 000000000..20a71ec1c
--- /dev/null
+++ b/src/org/traccar/web/AsyncServlet.java
@@ -0,0 +1,211 @@
+/*
+ * Copyright 2015 Anton Tananaev (anton.tananaev@gmail.com)
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.traccar.web;
+
+import java.io.IOException;
+import java.util.Collection;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.Iterator;
+import java.util.Map;
+import java.util.Map.Entry;
+import java.util.Set;
+import java.util.concurrent.TimeUnit;
+import javax.json.Json;
+import javax.json.JsonObjectBuilder;
+import javax.servlet.AsyncContext;
+import javax.servlet.ServletResponse;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+import org.jboss.netty.util.Timeout;
+import org.jboss.netty.util.TimerTask;
+import org.traccar.Context;
+import org.traccar.GlobalTimer;
+import org.traccar.database.ConnectionManager;
+import org.traccar.helper.Log;
+import org.traccar.model.Position;
+
+public class AsyncServlet extends BaseServlet {
+
+    private static final long ASYNC_TIMEOUT = 120000;
+    
+    @Override
+    protected boolean handle(String command, HttpServletRequest req, HttpServletResponse resp) throws Exception {
+        async(req.startAsync(), getUserId(req));
+        return true;
+    }
+    
+    public class AsyncSession {
+        
+        private static final boolean DEBUG_ASYNC = false;
+        
+        private static final long SESSION_TIMEOUT = 30;
+        private static final long REQUEST_TIMEOUT = 20;
+        
+        private boolean destroyed;
+        private final long userId;
+        private final Set<Long> devices = new HashSet<>();
+        private Timeout sessionTimeout;
+        private Timeout requestTimeout;
+        private final Map<Long, Position> positions = new HashMap<>();
+        private AsyncContext activeContext;
+        
+        private void logEvent(String message) {
+            if (DEBUG_ASYNC) {
+                Log.debug("AsyncSession: " + this.hashCode() + " destroyed: " + destroyed + " " + message);
+            }
+        }
+        
+        public AsyncSession(long userId, Collection<Long> devices) {
+            logEvent("create userId: " + userId + " devices: " + devices.size());
+            this.userId = userId;
+            this.devices.addAll(devices);
+
+            Collection<Position> initialPositions = Context.getConnectionManager().getInitialState(devices);
+            for (Position position : initialPositions) {
+                positions.put(position.getDeviceId(), position);
+            }
+            
+            Context.getConnectionManager().addListener(devices, dataListener);
+        }
+        
+        public boolean hasDevice(long deviceId) {
+            return devices.contains(deviceId);
+        }
+        
+        private final ConnectionManager.DataCacheListener dataListener = new ConnectionManager.DataCacheListener() {
+            @Override
+            public void onUpdate(Position position) {
+                synchronized (AsyncSession.this) {
+                    logEvent("onUpdate deviceId: " + position.getDeviceId());
+                    if (!destroyed) {
+                        if (requestTimeout != null) {
+                            requestTimeout.cancel();
+                            requestTimeout = null;
+                        }
+                        positions.put(position.getDeviceId(), position);
+                        if (activeContext != null) {
+                            response();
+                        }
+                    }
+                }
+            }
+        };
+        
+        private final TimerTask sessionTimer = new TimerTask() {
+            @Override
+            public void run(Timeout tmt) throws Exception {
+                synchronized (AsyncSession.this) {
+                    logEvent("sessionTimeout");
+                    Context.getConnectionManager().removeListener(devices, dataListener);
+                    synchronized (asyncSessions) {
+                        asyncSessions.remove(userId);
+                    }
+                    destroyed = true;
+                }
+            }
+        };
+                
+        private final TimerTask requestTimer = new TimerTask() {
+            @Override
+            public void run(Timeout tmt) throws Exception {
+                synchronized (AsyncSession.this) {
+                    logEvent("requestTimeout");
+                    if (!destroyed) {
+                        if (activeContext != null) {
+                            response();
+                        }
+                    }
+                }
+            }
+        };
+        
+        public synchronized void request(AsyncContext context) {
+            logEvent("request context: " + context.hashCode());
+            if (!destroyed) {
+                activeContext = context;
+                if (sessionTimeout != null) {
+                    sessionTimeout.cancel();
+                    sessionTimeout = null;
+                }
+
+                if (!positions.isEmpty()) {
+                    response();
+                } else {
+                    requestTimeout = GlobalTimer.getTimer().newTimeout(
+                            requestTimer, REQUEST_TIMEOUT, TimeUnit.SECONDS);
+                }
+            }
+        }
+        
+        private synchronized void response() {
+            logEvent("response context: " + activeContext.hashCode());
+            if (!destroyed) {
+                ServletResponse response = activeContext.getResponse();
+
+                JsonObjectBuilder result = Json.createObjectBuilder();
+                result.add("success", true);
+                result.add("data", JsonConverter.arrayToJson(positions.values()));
+                positions.clear();
+
+                try {
+                    response.getWriter().println(result.build().toString());
+                } catch (IOException error) {
+                    Log.warning(error);
+                }
+
+                activeContext.complete();
+                activeContext = null;
+
+                sessionTimeout = GlobalTimer.getTimer().newTimeout(
+                        sessionTimer, SESSION_TIMEOUT, TimeUnit.SECONDS);
+            }
+        }
+        
+    }
+    
+    private static final Map<Long, AsyncSession> asyncSessions = new HashMap<>();
+    
+    public static void sessionRefreshUser(long userId) {
+        asyncSessions.remove(userId);
+    }
+    
+    public static void sessionRefreshDevice(long deviceId) {
+        Iterator<Entry<Long, AsyncSession>> iterator = asyncSessions.entrySet().iterator();
+        while (iterator.hasNext()) {
+            if (iterator.next().getValue().hasDevice(deviceId)) {
+                iterator.remove();
+            }
+        }
+    }
+    
+    private void async(final AsyncContext context, long userId) {
+        
+        context.setTimeout(ASYNC_TIMEOUT);
+        HttpServletRequest req = (HttpServletRequest) context.getRequest();
+
+        synchronized (asyncSessions) {
+            
+            if (Boolean.valueOf(req.getParameter("first")) || !asyncSessions.containsKey(userId)) {
+                Collection<Long> devices = Context.getPermissionsManager().allowedDevices(userId);
+                asyncSessions.put(userId, new AsyncSession(userId, devices));
+            }
+            
+            asyncSessions.get(userId).request(context);
+        }
+    }
+
+}