Ticket #1628: Preferences_patch2.txt

### Eclipse Workspace Patch 1.0
#P josm
Index: src/org/openstreetmap/josm/data/Preferences.java
===================================================================
--- src/org/openstreetmap/josm/data/Preferences.java    (revision 965)
+++ src/org/openstreetmap/josm/data/Preferences.java    (working copy)
@@ -31,7 +31,14 @@
  * @author imi
  */
 public class Preferences {
-
+    
+    /**
+    * Internal storage for the preferenced directory. 
+    * Do not access this variable directly!
+    * @see #getPreferencesDirFile()
+    */
+    private File preferencesDirFile = null;
+     
        public static interface PreferenceChangedListener {
                void preferenceChanged(String key, String newValue);
        }
@@ -79,12 +86,24 @@
                return path + File.separator;
        }
 
-       public File getPreferencesDirFile() {
-               if (System.getenv("APPDATA") != null)
-                       return new File(System.getenv("APPDATA"), "JOSM");
-               return new File(System.getProperty("user.home"), ".josm");
-       }
-       
+    public File getPreferencesDirFile() {
+        if (preferencesDirFile != null)
+            return preferencesDirFile;
+        String path;
+        path = System.getProperty("josm.home");
+        if (path != null) {
+            preferencesDirFile = new File(path);
+        } else {
+            path = System.getenv("APPDATA");
+            if (path != null) {
+                preferencesDirFile = new File(path, "JOSM");
+            } else {
+                preferencesDirFile = new File(System.getProperty("user.home"), ".josm");
+            }
+        }
+        return preferencesDirFile;
+    }
+    
        public File getPluginsDirFile() {
                return new File(getPreferencesDirFile(), "plugins");
        }