src/tim/prune/load/json/JsonFileLoader.java

   1 package tim.prune.load.json;
   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 import java.util.Stack;
   9
  10 import tim.prune.App;
  11 import tim.prune.data.Field;
  12 import tim.prune.data.SourceInfo;
  13
  14
  15 /**
  16  * Class to handle the loading of GeoJSON files
  17  */
  18 public class JsonFileLoader
  19 {
  20         /** App for callback of file loading */
  21         private App _app = null;
  22         /** Stack of blocks */
  23         private Stack<JsonBlock> _jsonBlocks = null;
  24         /** List of points extracted */
  25         private ArrayList<JsonPoint> _jsonPoints = null;
  26         private boolean _newSegment = true;
  27
  28
  29         /**
  30          * Constructor
  31          * @param inApp App object
  32          */
  33         public JsonFileLoader(App inApp)
  34         {
  35                 _app = inApp;
  36                 _jsonBlocks = new Stack<JsonBlock>();
  37                 _jsonPoints = new ArrayList<JsonPoint>();
  38         }
  39
  40         /**
  41          * Open the selected file
  42          * @param inFile File to open
  43          */
  44         public void openFile(File inFile)
  45         {
  46                 BufferedReader reader = null;
  47                 try
  48                 {
  49                         reader = new BufferedReader(new FileReader(inFile));
  50                         String currLine = reader.readLine();
  51                         while (currLine != null)
  52                         {
  53                                 processTokensInLine(currLine);
  54                                 // Read next line, if any
  55                                 currLine = reader.readLine();
  56                         }
  57                 }
  58                 catch (IOException ioe) {
  59                         _app.showErrorMessage("error.load.dialogtitle", "error.load.noread");
  60                 }
  61                 finally
  62                 {
  63                         // close file ignoring errors
  64                         try {
  65                                 if (reader != null) reader.close();
  66                         }
  67                         catch (Exception e) {}
  68                 }
  69                 if (_jsonPoints.size() > 0)
  70                 {
  71                         Field[] fields = {Field.LATITUDE, Field.LONGITUDE, Field.ALTITUDE,
  72                                 Field.NEW_SEGMENT};
  73                         _app.informDataLoaded(fields, makeDataArray(),
  74                                 null, new SourceInfo(inFile, SourceInfo.FILE_TYPE.JSON), null);
  75                 }
  76                 // TODO: Show message if nothing was found?
  77         }
  78
  79         /** Split the given line from the json into tokens
  80          *  and process them one by one */
  81         private void processTokensInLine(String inLine)
  82         {
  83                 if (inLine == null) {return;}
  84                 String line = inLine.strip();
  85                 StringBuilder currToken = new StringBuilder();
  86                 boolean insideQuotes = false;
  87                 boolean previousSlash = false;
  88                 for (char x : line.toCharArray())
  89                 {
  90                         if (insideQuotes || x=='"') {
  91                                 currToken.append(x);
  92                         }
  93                         else
  94                         {
  95                                 if (" :,".indexOf(x) >= 0) {
  96                                         processToken(currToken.toString());
  97                                         currToken.setLength(0);
  98                                 }
  99                                 else if ("[{".indexOf(x) >= 0) {
 100                                         // start of a new block
 101                                         _jsonBlocks.add(new JsonBlock());
 102                                 }
 103                                 else if ("]}".indexOf(x) >= 0)
 104                                 {
 105                                         processToken(currToken.toString());
 106                                         currToken.setLength(0);
 107                                         // end of the current block
 108                                         processBlock(_jsonBlocks.pop());
 109                                 }
 110                                 else {
 111                                         currToken.append(x);
 112                                 }
 113                         }
 114                         if (x == '"' && !previousSlash) {insideQuotes = !insideQuotes;}
 115                         previousSlash = (x == '\\') && !previousSlash;
 116                 }
 117                 processToken(currToken.toString());
 118         }
 119
 120         private void processToken(String inToken)
 121         {
 122                 if (inToken == null || inToken.isBlank()) {return;}
 123                 if (inToken.equals("\"coordinates\"")) {
 124                         _newSegment = true;
 125                 }
 126                 _jsonBlocks.peek().addToken(inToken);
 127         }
 128
 129         /** Process the end of the given block */
 130         private void processBlock(JsonBlock inBlock)
 131         {
 132                 if (inBlock.areFieldsValid())
 133                 {
 134                         _jsonPoints.add(inBlock.createSinglePoint(_newSegment));
 135                         _newSegment = false;
 136                 }
 137                 else if (inBlock.areSingleCoordsValid())
 138                 {
 139                         // block contains a single point - pass to parent list
 140                         _jsonBlocks.peek().addSingleCoordsFrom(inBlock);
 141                 }
 142                 else if (inBlock.isCoordListValid())
 143                 {
 144                         // block contains a list of point coords
 145                         _jsonBlocks.peek().addCoordListFrom(inBlock);
 146                 }
 147                 else if (inBlock.hasValidCoordList())
 148                 {
 149                         for (int i=0; i<inBlock.getNumPoints(); i++)
 150                         {
 151                                 _jsonPoints.add(inBlock.createPointFromList(i));
 152                         }
 153                         _newSegment = true;
 154                 }
 155         }
 156
 157         /**
 158          * Make an object array from the data list
 159          * @return object array for loading
 160          */
 161         private Object[][] makeDataArray()
 162         {
 163                 Object[][] result = new Object[_jsonPoints.size()][];
 164                 for (int i=0; i<_jsonPoints.size(); i++) {
 165                         JsonPoint point = _jsonPoints.get(i);
 166                         result[i] = new String[] {point._latitude, point._longitude, point._altitude, point._newSegment?"1":"0"};
 167                 }
 168                 return result;
 169         }
 170 }