ROSMonitorManager.java

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/*
copyright 2014 UNL Nimbus Lab 

  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 edu.nimbus.glass;

import java.util.HashMap;
import java.util.Map;

import org.json.JSONException;
import org.json.JSONObject;

import android.util.Log;
import de.tavendo.autobahn.WebSocketConnection;
import de.tavendo.autobahn.WebSocketHandler;





public class ROSMonitorManager extends WebSocketHandler{

        //service to monitor ros in the background
        private ROSMonitorService _master;
        //The last warning received
        private String _lastWarning;
        //websocket
        WebSocketConnection mConnection;
        
        private Map<String, Long> message_times;

        public final static String WARN_TOPIC_NAME = "glass_warn";
        public final static String WARN_TOPIC_TYPE = "std_msgs/String";

        public ROSMonitorManager(ROSMonitorService master, WebSocketConnection conn){
                _lastWarning = "";
                message_times = new HashMap<String, Long>();
                _master = master;
                mConnection = conn;
        }

        @Override
        public void onOpen(){
                //Subscribe to the correct topic on open
                JSONObject req = new JSONObject();
                try {
                        req.put("op", "subscribe");
                        req.put("topic", WARN_TOPIC_NAME);
                        req.put("type", WARN_TOPIC_TYPE);

                } catch (JSONException e) {
                        Log.d("JSON ERROR", e.getMessage());
                }
                mConnection.sendTextMessage(req.toString());

        }       

        @Override
        public void onTextMessage(String payload){
                //try and parse the message and check to see if we have a new warning that warrants creating a  new live card.
                try {
                        JSONObject res = new JSONObject(payload);
                        String error_message = res.getJSONObject("msg").getString("data");
                        boolean val = check_display(error_message);
                        Log.d("DISPLAY WARN", val+"");
                        if(val){
                                _lastWarning = error_message;
                                _master.createWarning(error_message);
                        }

                } catch (JSONException e) {
                        Log.d("JSON ERROR", e.getMessage());
                }

        }

        public boolean check_display(String new_error){
                if(_lastWarning == new_error ){
                        return false;
                }else{
                        long now = System.currentTimeMillis();
                        if(message_times.containsKey(new_error)){
                                long last_time = message_times.get(new_error);
                                if((now - last_time > 5000)){
                                        message_times.put(new_error, now);
                                        return true;
                                }else{
                                        return false;
                                }
                                
                        }else{
                                message_times.put(new_error, now);
                                return true;
                        }
                        
                }
                
                
        }

        @Override
        public void onClose(int code, String reason) {
                Log.d("Data Closed", "Connection lost." + reason);

        }
        
        public void clearWarning(){
                _lastWarning = "";
        }

        public void setWarning(String text){
                _lastWarning = text;
        }

}