/*
* Copyright 2012 Google Inc.
*
* 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 com.fms.kccc.controller;
import static com.google.appengine.api.taskqueue.TaskOptions.Builder.withUrl;
import com.fms.kccc.server.Datastore;
import com.google.appengine.api.taskqueue.Queue;
import com.google.appengine.api.taskqueue.QueueFactory;
import com.google.appengine.api.taskqueue.TaskOptions;
import com.google.appengine.api.taskqueue.TaskOptions.Method;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
/**
* Servlet that adds a new message to all registered devices.
* <p>
* This servlet is used just by the browser (i.e., not device).
*/
@SuppressWarnings("serial")
public class SendAllMessagesServlet extends BaseServlet {
/**
* Processes the request to add a new message.
*/
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp)
throws IOException, ServletException {
List<String> devices = Datastore.getDevices();
String status;
if (devices.isEmpty()) {
status = "Message ignored as there is no device registered!";
} else {
Queue queue = QueueFactory.getQueue("gcm");
// NOTE: check below is for demonstration purposes; a real application
// could always send a multicast, even for just one recipient
if (devices.size() == 1) {
// send a single message using plain post
String device = devices.get(0);
queue.add(withUrl("/send").param(
SendMessageServlet.PARAMETER_DEVICE, device));
status = "Single message queued for registration id " + device;
} else {
// send a multicast message using JSON
// must split in chunks of 1000 devices (GCM limit)
int total = devices.size();
List<String> partialDevices = new ArrayList<String>(total);
int counter = 0;
int tasks = 0;
for (String device : devices) {
counter++;
partialDevices.add(device);
int partialSize = partialDevices.size();
if (partialSize == Datastore.MULTICAST_SIZE || counter == total) {
String multicastKey = Datastore.createMulticast(partialDevices);
logger.fine("Queuing " + partialSize + " devices on multicast " +
multicastKey);
TaskOptions taskOptions = TaskOptions.Builder
.withUrl("/send")
.param(SendMessageServlet.PARAMETER_MULTICAST, multicastKey)
.method(Method.POST);
queue.add(taskOptions);
partialDevices.clear();
tasks++;
}
}
status = "Queued tasks to send " + tasks + " multicast messages to " +
total + " devices";
}
}
req.setAttribute(HomeServlet.ATTRIBUTE_STATUS, status.toString());
getServletContext().getRequestDispatcher("/home").forward(req, resp);
}
}