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 _insideWaypoint = false;
  17         private boolean _insideName = false;
  18         private boolean _insideElevation = false;
  19         private boolean _insideTime = false;
  20         private boolean _startSegment = true;
  21         private String _name = null, _latitude = null, _longitude = null;
  22         private String _elevation = null;
  23         private String _time = null;
  24         private ArrayList _pointList = new ArrayList();
  25
  26
  27         /**
  28          * Receive the start of a tag
  29          * @see org.xml.sax.ContentHandler#startElement(java.lang.String, java.lang.String, java.lang.String, org.xml.sax.Attributes)
  30          */
  31         public void startElement(String uri, String localName, String qName,
  32                 Attributes attributes) throws SAXException
  33         {
  34                 // Read the parameters for waypoints and track points
  35                 if (qName.equalsIgnoreCase("wpt") || qName.equalsIgnoreCase("trkpt"))
  36                 {
  37                         _insideWaypoint = qName.equalsIgnoreCase("wpt");
  38                         int numAttributes = attributes.getLength();
  39                         for (int i=0; i<numAttributes; i++)
  40                         {
  41                                 String att = attributes.getQName(i);
  42                                 if (att.equals("lat")) {_latitude = attributes.getValue(i);}
  43                                 else if (att.equals("lon")) {_longitude = attributes.getValue(i);}
  44                         }
  45                         _elevation = null;
  46                         _name = null;
  47                         _time = null;
  48                 }
  49                 else if (qName.equalsIgnoreCase("ele"))
  50                 {
  51                         _insideElevation = true;
  52                 }
  53                 else if (qName.equalsIgnoreCase("name"))
  54                 {
  55                         _insideName = true;
  56                 }
  57                 else if (qName.equalsIgnoreCase("time"))
  58                 {
  59                         _insideTime = true;
  60                 }
  61                 else if (qName.equalsIgnoreCase("trkseg"))
  62                 {
  63                         _startSegment = true;
  64                 }
  65                 super.startElement(uri, localName, qName, attributes);
  66         }
  67
  68
  69         /**
  70          * Process end tag
  71          * @see org.xml.sax.ContentHandler#endElement(java.lang.String, java.lang.String, java.lang.String)
  72          */
  73         public void endElement(String uri, String localName, String qName)
  74                 throws SAXException
  75         {
  76                 if (qName.equalsIgnoreCase("wpt") || qName.equalsIgnoreCase("trkpt"))
  77                 {
  78                         processPoint();
  79                 }
  80                 else if (qName.equalsIgnoreCase("ele"))
  81                 {
  82                         _insideElevation = false;
  83                 }
  84                 else if (qName.equalsIgnoreCase("name"))
  85                 {
  86                         _insideName = false;
  87                 }
  88                 else if (qName.equalsIgnoreCase("time"))
  89                 {
  90                         _insideTime = false;
  91                 }
  92                 super.endElement(uri, localName, qName);
  93         }
  94
  95
  96         /**
  97          * Process character text (inside tags or between them)
  98          * @see org.xml.sax.ContentHandler#characters(char[], int, int)
  99          */
 100         public void characters(char[] ch, int start, int length)
 101                 throws SAXException
 102         {
 103                 String value = new String(ch, start, length);
 104                 if (_insideName && _insideWaypoint) {_name = checkCharacters(_name, value);}
 105                 else if (_insideElevation) {_elevation = checkCharacters(_elevation, value);}
 106                 else if (_insideTime) {_time = checkCharacters(_time, value);}
 107                 super.characters(ch, start, length);
 108         }
 109
 110
 111         /**
 112          * Check to concatenate partially-received values, if necessary
 113          * @param inVariable variable containing characters received until now
 114          * @param inValue new value received
 115          * @return concatenation
 116          */
 117         private static String checkCharacters(String inVariable, String inValue)
 118         {
 119                 if (inVariable == null) {return inValue;}
 120                 return inVariable + inValue;
 121         }
 122
 123
 124         /**
 125          * Process a point, either a waypoint or track point
 126          */
 127         private void processPoint()
 128         {
 129                 // Put the values into a String array matching the order in getFieldArray()
 130                 String[] values = new String[6];
 131                 values[0] = _latitude; values[1] = _longitude;
 132                 values[2] = _elevation; values[3] = _name;
 133                 values[4] = _time;
 134                 if (_startSegment && !_insideWaypoint) {
 135                         values[5] = "1";
 136                         _startSegment = false;
 137                 }
 138                 _pointList.add(values);
 139         }
 140
 141
 142         /**
 143          * @see tim.prune.load.xml.XmlHandler#getFieldArray()
 144          */
 145         public Field[] getFieldArray()
 146         {
 147                 final Field[] fields = {Field.LATITUDE, Field.LONGITUDE, Field.ALTITUDE,
 148                         Field.WAYPT_NAME, Field.TIMESTAMP, Field.NEW_SEGMENT};
 149                 return fields;
 150         }
 151
 152
 153         /**
 154          * Return the parsed information as a 2d array
 155          * @see tim.prune.load.xml.XmlHandler#getDataArray()
 156          */
 157         public String[][] getDataArray()
 158         {
 159                 int numPoints = _pointList.size();
 160                 // construct data array
 161                 String[][] result = new String[numPoints][];
 162                 for (int i=0; i<numPoints; i++)
 163                 {
 164                         result[i] = (String[]) _pointList.get(i);
 165                 }
 166                 return result;
 167         }
 168 }