tim/prune/load/NmeaFileLoader.java

   1 package tim.prune.load;
   2
   3 import java.io.BufferedReader;
   4 import java.io.File;
   5 import java.io.FileReader;
   6 import java.io.IOException;
   7 import java.util.ArrayList;
   8
   9 import tim.prune.App;
  10 import tim.prune.data.Altitude;
  11 import tim.prune.data.Field;
  12 import tim.prune.data.SourceInfo;
  13
  14 /**
  15  * Class to handle the loading of Nmea files
  16  */
  17 public class NmeaFileLoader
  18 {
  19         /** App for callback of file loading */
  20         private App _app = null;
  21
  22         /**
  23          * Constructor
  24          * @param inApp App object
  25          */
  26         public NmeaFileLoader(App inApp)
  27         {
  28                 _app = inApp;
  29         }
  30
  31         /**
  32          * Open the selected file
  33          * @param inFile File to open
  34          */
  35         public void openFile(File inFile)
  36         {
  37                 BufferedReader reader = null;
  38                 ArrayList<NmeaMessage> messages = new ArrayList<NmeaMessage>();
  39                 String lastDate = null;
  40                 try
  41                 {
  42                         reader = new BufferedReader(new FileReader(inFile));
  43                         String currLine = reader.readLine();
  44                         boolean newSegment = true;
  45                         while (currLine != null)
  46                         {
  47                                 // Try to make an NmeaMessage object for each line of file
  48                                 if (currLine.trim().length() > 0)
  49                                 {
  50                                         NmeaMessage message = processGGA(currLine);
  51                                         if (message != null)
  52                                         {
  53                                                 if (message.hasFix())
  54                                                 {
  55                                                         message.setSegment(newSegment);
  56                                                         message.setDate(lastDate);
  57                                                         // add message to list
  58                                                         messages.add(message);
  59                                                 }
  60                                                 // Start a new segment if fix lost
  61                                                 newSegment = !message.hasFix();
  62                                         }
  63                                         else {
  64                                                 String date = getDateFromRMC(currLine);
  65                                                 if (date != null)
  66                                                 {
  67                                                         if (lastDate == null && !messages.isEmpty()) {
  68                                                                 // Backfill first few messages received before the first date
  69                                                                 for (int m=0; m<messages.size(); m++) {
  70                                                                         messages.get(m).setDate(date);
  71                                                                 }
  72                                                         }
  73                                                         lastDate = date;
  74                                                 }
  75                                         }
  76                                 }
  77                                 // Read next line, if any
  78                                 currLine = reader.readLine();
  79                         }
  80                 }
  81                 catch (IOException ioe) {
  82                         _app.showErrorMessage("error.load.dialogtitle", "error.load.noread");
  83                 }
  84                 finally
  85                 {
  86                         // close file ignoring errors
  87                         try {
  88                                 if (reader != null) reader.close();
  89                         }
  90                         catch (Exception e) {}
  91                 }
  92                 if (messages.size() > 0)
  93                 {
  94                         _app.informDataLoaded(getFieldArray(), makeDataArray(messages),
  95                                 Altitude.Format.METRES, new SourceInfo(inFile, SourceInfo.FILE_TYPE.NMEA));
  96                 }
  97         }
  98
  99         /**
 100          * Process the given GGA sentence and return the message
 101          * @param inLine line to process
 102          * @return message object
 103          */
 104         private static NmeaMessage processGGA(String inLine)
 105         {
 106                 // Only consider lines which are long enough and begin with the GPS position sentence
 107                 if (inLine == null || inLine.length() < 20 || !inLine.startsWith("$GPGGA")) {
 108                         return null;
 109                 }
 110                 // Assume comma delimiter, split into array
 111                 String[] splitLine = inLine.split(",");
 112                 if (splitLine != null && splitLine.length >= 10)
 113                 {
 114                         return new NmeaMessage(splitLine[2] + splitLine[3], // latitude
 115                                 splitLine[4] + splitLine[5], // longitude
 116                                 splitLine[9], // altitude
 117                                 splitLine[1], // timestamp
 118                                 splitLine[6]); // fix
 119                 }
 120                 // Couldn't parse it, return null
 121                 return null;
 122         }
 123
 124         /**
 125          * Process the given MRC sentence and return the date
 126          * @param inLine line to process
 127          * @return date, if any
 128          */
 129         private static String getDateFromRMC(String inLine)
 130         {
 131                 // Only consider lines which are long enough and begin with the RMC sentence
 132                 if (inLine == null || inLine.length() < 20 || !inLine.startsWith("$GPRMC")) {
 133                         return null;
 134                 }
 135                 // Assume comma delimiter, split into array
 136                 String[] splitLine = inLine.split(",");
 137                 if (splitLine != null && splitLine.length >= 10)
 138                 {
 139                         return splitLine[9]; // date in position 9
 140                 }
 141                 // Couldn't parse it, return null
 142                 return null;
 143         }
 144
 145         /**
 146          * Make an object array from the data list
 147          * @param inList list of messages
 148          * @return object array for loading
 149          */
 150         private static Object[][] makeDataArray(ArrayList<NmeaMessage> inList)
 151         {
 152                 Object[][] result = new Object[inList.size()][];
 153                 for (int i=0; i<inList.size(); i++) {
 154                         result[i] = inList.get(i).getStrings();
 155                 }
 156                 return result;
 157         }
 158
 159         /**
 160          * @see tim.prune.load.xml.XmlHandler#getFieldArray()
 161          */
 162         public Field[] getFieldArray()
 163         {
 164                 final Field[] fields = {Field.LATITUDE, Field.LONGITUDE, Field.ALTITUDE,
 165                         Field.TIMESTAMP, Field.NEW_SEGMENT};
 166                 return fields;
 167         }
 168 }