tim/prune/FileDropHandler.java

   1 package tim.prune;
   2
   3 import java.awt.datatransfer.DataFlavor;
   4 import java.io.File;
   5 import java.net.URI;
   6 import java.util.ArrayList;
   7
   8 import javax.swing.TransferHandler;
   9
  10 /**
  11  * Class to listen for drag/drop events and react to dropping files on to the application
  12  */
  13 public class FileDropHandler extends TransferHandler
  14 {
  15         /** App object for passing results back to */
  16         private App _app = null;
  17
  18         /** Fixed flavour in case the java file list flavour isn't available */
  19         private static DataFlavor _uriListFlavour = null;
  20
  21         /** Static block to initialise the list flavour */
  22         static
  23         {
  24                 try {_uriListFlavour = new DataFlavor("text/uri-list;class=java.lang.String");
  25                 } catch (ClassNotFoundException nfe) {}
  26         }
  27
  28
  29         /**
  30          * Constructor
  31          * @param inApp App object to pass results of drop back to
  32          */
  33         public FileDropHandler(App inApp)
  34         {
  35                 _app = inApp;
  36         }
  37
  38         /**
  39          * Check if the object being dragged can be accepted
  40          * @param inSupport object to check
  41          */
  42         public boolean canImport(TransferSupport inSupport)
  43         {
  44                 boolean retval = inSupport.isDataFlavorSupported(DataFlavor.javaFileListFlavor)
  45                         || inSupport.isDataFlavorSupported(_uriListFlavour);
  46                 // Modify icon to show a copy, not a move (+ icon on cursor)
  47                 if (retval) {
  48                         inSupport.setDropAction(COPY);
  49                 }
  50                 return retval;
  51         }
  52
  53         /**
  54          * Accept the incoming data and pass it on to the App
  55          * @param inSupport contents of drop
  56          */
  57         public boolean importData(TransferSupport inSupport)
  58         {
  59                 if (!canImport(inSupport)) {return false;} // not allowed
  60
  61                 boolean success = false;
  62                 ArrayList<File> dataFiles = new ArrayList<File>();
  63
  64                 // Try a java file list flavour first
  65                 try
  66                 {
  67                         @SuppressWarnings("unchecked")
  68                         java.util.List<File> fileList = (java.util.List<File>)
  69                         inSupport.getTransferable().getTransferData(DataFlavor.javaFileListFlavor);
  70                         success = true;
  71
  72                         for (File f : fileList)
  73                         {
  74                                 if (f != null && f.exists())
  75                                 {
  76                                         if (f.isDirectory()) {
  77                                                 addDirectoryToList(f, dataFiles);
  78                                         }
  79                                         else if (f.isFile()) {
  80                                                 dataFiles.add(f);
  81                                         }
  82                                 }
  83                         }
  84                 } catch (Exception e) {}  // exception caught, probably missing a javafilelist flavour - just continue
  85
  86                 // If that didn't work, try a list of strings instead
  87                 if (!success)
  88                 {
  89                         try
  90                         {
  91                                 String pathList = inSupport.getTransferable().getTransferData(_uriListFlavour).toString();
  92                                 success = true;
  93
  94                                 for (String s : pathList.split("[\n\r]+"))
  95                                 {
  96                                         if (s != null && !s.equals(""))
  97                                         {
  98                                                 File f = new File(new URI(s));
  99                                                 if (f.exists())
 100                                                 {
 101                                                         if (f.isDirectory()) {
 102                                                                 addDirectoryToList(f, dataFiles);
 103                                                         }
 104                                                         else if (f.isFile()) {
 105                                                                 dataFiles.add(f);
 106                                                         }
 107                                                 }
 108                                         }
 109                                 }
 110                         } catch (Exception e) {
 111                                 System.err.println("exception: " + e.getClass().getName() + " - " + e.getMessage());
 112                                 return false;
 113                         }
 114                 }
 115
 116                 // Pass files back to app
 117                 if (!dataFiles.isEmpty()) {
 118                         _app.loadDataFiles(dataFiles);
 119                 }
 120                 return true;
 121         }
 122
 123
 124         /**
 125          * Recursively-called method to add files from the given directory (and its subdirectories)
 126          * to the given list of files
 127          * @param inDir directory to add
 128          * @param inList file list to append to
 129          */
 130         private void addDirectoryToList(File inDir, ArrayList<File> inList)
 131         {
 132                 if (inDir != null && inDir.exists() && inDir.canRead() && inDir.isDirectory() && inList != null)
 133                 {
 134                         for (String path : inDir.list())
 135                         {
 136                                 if (path != null)
 137                                 {
 138                                         File f = new File(inDir, path);
 139                                         if (f.exists() && f.canRead())
 140                                         {
 141                                                 if (f.isFile())
 142                                                 {
 143                                                         // Add the found file to the list (if it's not in there already)
 144                                                         if (!inList.contains(f)) {
 145                                                                 inList.add(f);
 146                                                         }
 147                                                 }
 148                                                 else if (f.isDirectory())
 149                                                 {
 150                                                         // Recursively add the files from subdirectories
 151                                                         addDirectoryToList(f, inList);
 152                                                 }
 153                                         }
 154                                 }
 155                         }
 156                 }
 157         }
 158 }