Introduce FatalException

Rather than throwing a generic RuntimeException for fatal / catastrophic
exceptions (which are typically due to developer error) throw
FatalException.

src/main/java/io/bitsquare/FatalException.java

@@ -0,0 +1,30 @@
+/*
+ * This file is part of Bitsquare.
+ *
+ * Bitsquare is free software: you can redistribute it and/or modify it
+ * under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or (at
+ * your option) any later version.
+ *
+ * Bitsquare is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU Affero General Public
+ * License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with Bitsquare. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package io.bitsquare;
+
+@SuppressWarnings("serializable")
+public class FatalException extends RuntimeException {
+
+    public FatalException(String format, Object... args) {
+        super(String.format(format, args));
+    }
+
+    public FatalException(Throwable cause, String format, Object... args) {
+        super(String.format(format, args), cause);
+    }
+}

src/main/java/io/bitsquare/util/ViewLoader.java

@@ -17,6 +17,7 @@
 
 package io.bitsquare.util;
 
+import io.bitsquare.FatalException;
 import io.bitsquare.gui.Navigation;
 import io.bitsquare.locale.BSResources;
 
@@ -56,6 +57,9 @@ public class ViewLoader {
 
     public ViewLoader(Navigation.Item navItem, boolean useCaching) {
         this.url = ViewLoader.class.getResource(navItem.getFxmlUrl());
+        if (this.url == null) {
+            throw new FatalException("'%s' could not be loaded as a resource", navItem.getFxmlUrl());
+        }
 
         isCached = useCaching && cachedGUIItems.containsKey(url);
         if (!isCached) {
@@ -85,7 +89,7 @@ public class ViewLoader {
             cachedGUIItems.put(url, item);
             return result;
         } catch (IOException e) {
-            throw new RuntimeException("Failed to load view at " + url, e);
+            throw new FatalException(e, "Failed to load view at %s", url);
         }
     }