Version 20.4, May 2021

[GpsPrune.git] / src / tim / prune / load / json / JsonFileLoader.java

diff --git a/src/tim/prune/load/json/JsonFileLoader.java b/src/tim/prune/load/json/JsonFileLoader.java
new file mode 100644 (file)
index 0000000..e1df666
--- /dev/null
+++ b/src/tim/prune/load/json/JsonFileLoader.java
@@ -0,0 +1,170 @@
+package tim.prune.load.json;
+
+import java.io.BufferedReader;
+import java.io.File;
+import java.io.FileReader;
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Stack;
+
+import tim.prune.App;
+import tim.prune.data.Field;
+import tim.prune.data.SourceInfo;
+
+
+/**
+ * Class to handle the loading of GeoJSON files
+ */
+public class JsonFileLoader
+{
+       /** App for callback of file loading */
+       private App _app = null;
+       /** Stack of blocks */
+       private Stack<JsonBlock> _jsonBlocks = null;
+       /** List of points extracted */
+       private ArrayList<JsonPoint> _jsonPoints = null;
+       private boolean _newSegment = true;
+
+
+       /**
+        * Constructor
+        * @param inApp App object
+        */
+       public JsonFileLoader(App inApp)
+       {
+               _app = inApp;
+               _jsonBlocks = new Stack<JsonBlock>();
+               _jsonPoints = new ArrayList<JsonPoint>();
+       }
+
+       /**
+        * Open the selected file
+        * @param inFile File to open
+        */
+       public void openFile(File inFile)
+       {
+               BufferedReader reader = null;
+               try
+               {
+                       reader = new BufferedReader(new FileReader(inFile));
+                       String currLine = reader.readLine();
+                       while (currLine != null)
+                       {
+                               processTokensInLine(currLine);
+                               // Read next line, if any
+                               currLine = reader.readLine();
+                       }
+               }
+               catch (IOException ioe) {
+                       _app.showErrorMessage("error.load.dialogtitle", "error.load.noread");
+               }
+               finally
+               {
+                       // close file ignoring errors
+                       try {
+                               if (reader != null) reader.close();
+                       }
+                       catch (Exception e) {}
+               }
+               if (_jsonPoints.size() > 0)
+               {
+                       Field[] fields = {Field.LATITUDE, Field.LONGITUDE, Field.ALTITUDE,
+                               Field.NEW_SEGMENT};
+                       _app.informDataLoaded(fields, makeDataArray(),
+                               null, new SourceInfo(inFile, SourceInfo.FILE_TYPE.JSON), null);
+               }
+               // TODO: Show message if nothing was found?
+       }
+
+       /** Split the given line from the json into tokens
+        *  and process them one by one */
+       private void processTokensInLine(String inLine)
+       {
+               if (inLine == null) {return;}
+               String line = inLine.strip();
+               StringBuilder currToken = new StringBuilder();
+               boolean insideQuotes = false;
+               boolean previousSlash = false;
+               for (char x : line.toCharArray())
+               {
+                       if (insideQuotes || x=='"') {
+                               currToken.append(x);
+                       }
+                       else
+                       {
+                               if (" :,".indexOf(x) >= 0) {
+                                       processToken(currToken.toString());
+                                       currToken.setLength(0);
+                               }
+                               else if ("[{".indexOf(x) >= 0) {
+                                       // start of a new block
+                                       _jsonBlocks.add(new JsonBlock());
+                               }
+                               else if ("]}".indexOf(x) >= 0)
+                               {
+                                       processToken(currToken.toString());
+                                       currToken.setLength(0);
+                                       // end of the current block
+                                       processBlock(_jsonBlocks.pop());
+                               }
+                               else {
+                                       currToken.append(x);
+                               }
+                       }
+                       if (x == '"' && !previousSlash) {insideQuotes = !insideQuotes;}
+                       previousSlash = (x == '\\') && !previousSlash;
+               }
+               processToken(currToken.toString());
+       }
+
+       private void processToken(String inToken)
+       {
+               if (inToken == null || inToken.isBlank()) {return;}
+               if (inToken.equals("\"coordinates\"")) {
+                       _newSegment = true;
+               }
+               _jsonBlocks.peek().addToken(inToken);
+       }
+
+       /** Process the end of the given block */
+       private void processBlock(JsonBlock inBlock)
+       {
+               if (inBlock.areFieldsValid())
+               {
+                       _jsonPoints.add(inBlock.createSinglePoint(_newSegment));
+                       _newSegment = false;
+               }
+               else if (inBlock.areSingleCoordsValid())
+               {
+                       // block contains a single point - pass to parent list
+                       _jsonBlocks.peek().addSingleCoordsFrom(inBlock);
+               }
+               else if (inBlock.isCoordListValid())
+               {
+                       // block contains a list of point coords
+                       _jsonBlocks.peek().addCoordListFrom(inBlock);
+               }
+               else if (inBlock.hasValidCoordList())
+               {
+                       for (int i=0; i<inBlock.getNumPoints(); i++)
+                       {
+                               _jsonPoints.add(inBlock.createPointFromList(i));
+                       }
+                       _newSegment = true;
+               }
+       }
+
+       /**
+        * Make an object array from the data list
+        * @return object array for loading
+        */
+       private Object[][] makeDataArray()
+       {
+               Object[][] result = new Object[_jsonPoints.size()][];
+               for (int i=0; i<_jsonPoints.size(); i++) {
+                       JsonPoint point = _jsonPoints.get(i);
+                       result[i] = new String[] {point._latitude, point._longitude, point._altitude, point._newSegment?"1":"0"};
+               }
+               return result;
+       }
+}