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