JAL-1552 extra debug logging for dataflavor if drop has no data

diff --git a/src/jalview/gui/AlignFrame.java b/src/jalview/gui/AlignFrame.java
index 0419b6f..3e3780a 100644 (file)
--- a/src/jalview/gui/AlignFrame.java
+++ b/src/jalview/gui/AlignFrame.java
@@ -5038,6 +5038,7 @@ public class AlignFrame extends GAlignFrame implements DropTargetListener,
               "text/uri-list;class=java.lang.String");
       if (t.isDataFlavorSupported(DataFlavor.javaFileListFlavor))
       {
+        Cache.log.debug("Drop handled as javaFileListFlavor");
         // Works on Windows and MacOSX
         evt.acceptDrop(DnDConstants.ACTION_COPY_OR_MOVE);
         files = (java.util.List) t
@@ -5045,14 +5046,20 @@ public class AlignFrame extends GAlignFrame implements DropTargetListener,
       }
       else if (t.isDataFlavorSupported(uriListFlavor))
       {
+        Cache.log.debug("Drop handled as uriListFlavor");
         // This is used by Unix drag system
         evt.acceptDrop(DnDConstants.ACTION_COPY_OR_MOVE);
         String data = (String) t.getTransferData(uriListFlavor);
         if (data == null)
         {
+          Cache.log.debug("standard URIListFlavor (" + uriListFlavor
+                  + ") doesn't resolve. trying others.");
           // try 'best' dataflavor
           data = (String) t.getTransferData(DataFlavor
                   .selectBestTextFlavor(t.getTransferDataFlavors()));
+          Cache.log.debug("Dataflavor "
+                  + DataFlavor.selectBestTextFlavor(t
+                          .getTransferDataFlavors()) + " returned " + data);
         }
         files = new java.util.ArrayList(1);
         for (java.util.StringTokenizer st = new java.util.StringTokenizer(
@@ -5078,6 +5085,24 @@ public class AlignFrame extends GAlignFrame implements DropTargetListener,
             files.add(file.toString());
           }
         }
+        if (files.size() < 1)
+        {
+          Cache.log
+                  .debug("Couldn't resolve drop data with 'best text'. Here are the supported flavors:");
+          if (data == null && Cache.log.isDebugEnabled())
+          {
+            for (DataFlavor fl : t.getTransferDataFlavors())
+            {
+              Cache.log.debug("Supported transfer dataflavor: "
+                      + fl.toString());
+              Object df = t.getTransferData(fl);
+              if (df != null)
+              {
+                Cache.log.debug("Retrieves: " + df);
+              }
+            }
+          }
+        }
       }
     } catch (Exception e)
     {