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/*
* 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.http;
import java.io.IOException;
import java.util.Collection;
import java.util.HashMap;
import java.util.Map;
import java.util.concurrent.TimeUnit;
import javax.json.Json;
import javax.json.JsonObjectBuilder;
import javax.servlet.AsyncContext;
import javax.servlet.ServletException;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServlet;
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.DataCache;
import org.traccar.helper.Log;
import org.traccar.model.Position;
import org.traccar.model.User;
public class AsyncServlet extends HttpServlet {
private static final long ASYNC_TIMEOUT = 120000;
@Override
protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
async(req.startAsync());
}
public class AsyncSession {
private static final boolean DEBUG_ASYNC = false;
private static final long SESSION_TIMEOUT = 30;
private static final long REQUEST_TIMEOUT = 10;
private boolean destroyed;
private final long userId;
private final Collection<Long> devices;
private Timeout sessionTimeout;
private Timeout requestTimeout;
private final Map<Long, Position> positions = new HashMap<Long, Position>();
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 = devices;
Collection<Position> initialPositions = Context.getDataCache().getInitialState(devices);
for (Position position : initialPositions) {
positions.put(position.getDeviceId(), position);
}
Context.getDataCache().addListener(devices, dataListener);
}
private final DataCache.DataCacheListener dataListener = new DataCache.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.getDataCache().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 final Map<Long, AsyncSession> asyncSessions = new HashMap<Long, AsyncSession>();
private void async(final AsyncContext context) {
context.setTimeout(ASYNC_TIMEOUT);
HttpServletRequest req = (HttpServletRequest) context.getRequest();
User user = (User) req.getSession().getAttribute(MainServlet.USER_KEY);
synchronized (asyncSessions) {
if (Boolean.valueOf(req.getParameter("first")) || !asyncSessions.containsKey(user.getId())) {
Collection<Long> devices = Context.getPermissionsManager().allowedDevices(user.getId());
asyncSessions.put(user.getId(), new AsyncSession(user.getId(), devices));
}
asyncSessions.get(user.getId()).request(context);
}
}
}
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