tim/prune/load/xml/GpxHandler.java

   1 package tim.prune.load.xml;
   2
   3 import java.util.ArrayList;
   4
   5 import org.xml.sax.Attributes;
   6 import org.xml.sax.SAXException;
   7
   8 import tim.prune.data.Field;
   9
  10
  11 /**
  12  * Class for handling specifics of parsing Gpx files
  13  */
  14 public class GpxHandler extends XmlHandler
  15 {
  16         private boolean _insideName = false;
  17         private boolean _insideElevation = false;
  18         private boolean _insideTime = false;
  19         private String _name = null, _latitude = null, _longitude = null;
  20         private String _elevation = null;
  21         private String _time = null;
  22         private ArrayList _pointList = new ArrayList();
  23
  24
  25         /**
  26          * Receive the start of a tag
  27          * @see org.xml.sax.ContentHandler#startElement(java.lang.String, java.lang.String, java.lang.String, org.xml.sax.Attributes)
  28          */
  29         public void startElement(String uri, String localName, String qName,
  30                         Attributes attributes) throws SAXException
  31         {
  32                 // Read the parameters for waypoints and track points
  33                 if (qName.equalsIgnoreCase("wpt") || qName.equalsIgnoreCase("trkpt"))
  34                 {
  35                         int numAttributes = attributes.getLength();
  36                         for (int i=0; i<numAttributes; i++)
  37                         {
  38                                 String att = attributes.getQName(i);
  39                                 if (att.equals("lat")) {_latitude = attributes.getValue(i);}
  40                                 else if (att.equals("lon")) {_longitude = attributes.getValue(i);}
  41                         }
  42                         _elevation = null;
  43                         _name = null;
  44                         _time = null;
  45                 }
  46                 else if (qName.equalsIgnoreCase("ele"))
  47                 {
  48                         _insideElevation = true;
  49                 }
  50                 else if (qName.equalsIgnoreCase("name"))
  51                 {
  52                         _insideName = true;
  53                 }
  54                 else if (qName.equalsIgnoreCase("time"))
  55                 {
  56                         _insideTime = true;
  57                 }
  58                 super.startElement(uri, localName, qName, attributes);
  59         }
  60
  61
  62         /**
  63          * Process end tag
  64          * @see org.xml.sax.ContentHandler#endElement(java.lang.String, java.lang.String, java.lang.String)
  65          */
  66         public void endElement(String uri, String localName, String qName)
  67         throws SAXException
  68         {
  69                 if (qName.equalsIgnoreCase("wpt") || qName.equalsIgnoreCase("trkpt"))
  70                 {
  71                         processPoint();
  72                 }
  73                 else if (qName.equalsIgnoreCase("ele"))
  74                 {
  75                         _insideElevation = false;
  76                 }
  77                 else if (qName.equalsIgnoreCase("name"))
  78                 {
  79                         _insideName = false;
  80                 }
  81                 else if (qName.equalsIgnoreCase("time"))
  82                 {
  83                         _insideTime = false;
  84                 }
  85                 super.endElement(uri, localName, qName);
  86         }
  87
  88
  89         /**
  90          * Process character text (inside tags or between them)
  91          * @see org.xml.sax.ContentHandler#characters(char[], int, int)
  92          */
  93         public void characters(char[] ch, int start, int length)
  94                         throws SAXException
  95         {
  96                 String value = new String(ch, start, length);
  97                 if (_insideName) {_name = checkCharacters(_name, value);}
  98                 else if (_insideElevation) {_elevation = checkCharacters(_elevation, value);}
  99                 else if (_insideTime) {_time = checkCharacters(_time, value);}
 100                 super.characters(ch, start, length);
 101         }
 102
 103
 104         /**
 105          * Check to concatenate partially-received values, if necessary
 106          * @param inVariable variable containing characters received until now
 107          * @param inValue new value received
 108          * @return concatenation
 109          */
 110         private static String checkCharacters(String inVariable, String inValue)
 111         {
 112                 if (inVariable == null) {return inValue;}
 113                 return inVariable + inValue;
 114         }
 115
 116
 117         /**
 118          * Process a point, either a waypoint or track point
 119          */
 120         private void processPoint()
 121         {
 122                 // Put the values into a String array matching the order in getFieldArray()
 123                 String[] values = new String[5];
 124                 values[0] = _latitude; values[1] = _longitude;
 125                 values[2] = _elevation; values[3] = _name;
 126                 values[4] = _time;
 127                 _pointList.add(values);
 128         }
 129
 130
 131         /**
 132          * @see tim.prune.load.xml.XmlHandler#getFieldArray()
 133          */
 134         public Field[] getFieldArray()
 135         {
 136                 final Field[] fields = {Field.LATITUDE, Field.LONGITUDE, Field.ALTITUDE,
 137                         Field.WAYPT_NAME, Field.TIMESTAMP};
 138                 return fields;
 139         }
 140
 141
 142         /**
 143          * Return the parsed information as a 2d array
 144          * @see tim.prune.load.xml.XmlHandler#getDataArray()
 145          */
 146         public String[][] getDataArray()
 147         {
 148                 int numPoints = _pointList.size();
 149                 // construct data array
 150                 String[][] result = new String[numPoints][];
 151                 for (int i=0; i<numPoints; i++)
 152                 {
 153                         result[i] = (String[]) _pointList.get(i);
 154                 }
 155                 return result;
 156         }
 157 }