better save error dialogs

src/com/bytezone/diskbrowser/disk/SectorListConverter.java

@@ -17,8 +17,7 @@ public class SectorListConverter
     sectors = new ArrayList<> ();
     sectorText = text;
 
-    String[] blocks = text.split (";");
-    for (String s : blocks)
+    for (String s : text.split (";"))
     {
       int pos = s.indexOf ('-');
       if (pos > 0)

src/com/bytezone/diskbrowser/gui/AbstractSaveAction.java

@@ -2,6 +2,7 @@ package com.bytezone.diskbrowser.gui;
 
 import java.io.File;
 import java.io.IOException;
+import java.nio.file.FileAlreadyExistsException;
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.nio.file.StandardOpenOption;
@@ -52,10 +53,17 @@ public abstract class AbstractSaveAction extends DefaultAction
         JOptionPane.showMessageDialog (null,
             String.format ("File %s saved", file.getName ()));
       }
+      catch (FileAlreadyExistsException e)
+      {
+        JOptionPane.showMessageDialog (null,
+            "File " + file.getName () + " already exists", "Failed",
+            JOptionPane.ERROR_MESSAGE);
+      }
       catch (IOException e)
       {
         e.printStackTrace ();
-        JOptionPane.showMessageDialog (null, "File failed to save");
+        JOptionPane.showMessageDialog (null, "File failed to save - " + e.getMessage (),
+            "Failed", JOptionPane.ERROR_MESSAGE);
       }
     }
   }

src/com/bytezone/diskbrowser/gui/SaveSectorsAction.java

@@ -2,9 +2,13 @@ package com.bytezone.diskbrowser.gui;
 
 import java.awt.event.ActionEvent;
 import java.io.File;
+import java.util.List;
 
 import javax.swing.JOptionPane;
 
+import com.bytezone.diskbrowser.disk.Disk;
+import com.bytezone.diskbrowser.disk.DiskAddress;
+
 // -----------------------------------------------------------------------------------//
 class SaveSectorsAction extends AbstractSaveAction implements SectorSelectionListener
 // -----------------------------------------------------------------------------------//
@@ -30,8 +34,14 @@ class SaveSectorsAction extends AbstractSaveAction implements SectorSelectionLis
       return;
     }
 
-    setSelectedFile (new File ("savedSectors.bin"));
-    saveBuffer (event.getFormattedDisk ().getDisk ().readBlocks (event.getSectors ()));
+    // block 0 will not read when it is the only DiskAddress in the list
+    List<DiskAddress> blocks = event.getSectors ();
+    Disk disk = event.getFormattedDisk ().getDisk ();
+    byte[] buffer =
+        blocks.size () == 1 ? disk.readBlock (blocks.get (0)) : disk.readBlocks (blocks);
+
+    setSelectedFile (new File ("SavedSectors.bin"));
+    saveBuffer (buffer);
   }
 
   // ---------------------------------------------------------------------------------//

src/com/bytezone/diskbrowser/gui/SectorSelectedEvent.java

@@ -12,7 +12,7 @@ class SectorSelectedEvent extends EventObject
 // -----------------------------------------------------------------------------------//
 {
   private final List<DiskAddress> sectors;
-  private final FormattedDisk owner;
+  private final FormattedDisk owner;          // for dual-format disks
   boolean redo;
 
   // ---------------------------------------------------------------------------------//
@@ -20,6 +20,7 @@ class SectorSelectedEvent extends EventObject
   // ---------------------------------------------------------------------------------//
   {
     super (source);
+
     this.sectors = sectors;
     // always store the parent if this disk is part of a dual-dos disk
     this.owner = owner.getParent () == null ? owner : owner.getParent ();
@@ -44,8 +45,10 @@ class SectorSelectedEvent extends EventObject
   // ---------------------------------------------------------------------------------//
   {
     StringBuilder text = new StringBuilder ();
-    SectorListConverter slc = new SectorListConverter (sectors);
-    text.append (slc.sectorText);
+
+    SectorListConverter sectorListConverter = new SectorListConverter (sectors);
+    text.append (sectorListConverter.sectorText);
+
     return text.toString ();
   }