From e4ea6d7f716032db6a292b6716b97e180f48f891 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Cl=C3=A9ment=20Fournier?= <clement.fournier76@gmail.com>
Date: Thu, 24 Jan 2019 00:25:58 +0100
Subject: [PATCH] Improve resilience to unknown language version

---
 .../fxdesigner/SourceEditorController.java    |  2 +-
 .../util/fxdesigner/XPathPanelController.java |  2 +-
 .../util/fxdesigner/util/DesignerUtil.java    | 35 +++++++++++++++----
 3 files changed, 31 insertions(+), 8 deletions(-)

diff --git a/pmd-ui/src/main/java/net/sourceforge/pmd/util/fxdesigner/SourceEditorController.java b/pmd-ui/src/main/java/net/sourceforge/pmd/util/fxdesigner/SourceEditorController.java
index 46d9c6c206..3db0d477fe 100644
--- a/pmd-ui/src/main/java/net/sourceforge/pmd/util/fxdesigner/SourceEditorController.java
+++ b/pmd-ui/src/main/java/net/sourceforge/pmd/util/fxdesigner/SourceEditorController.java
@@ -184,7 +184,7 @@ public class SourceEditorController extends AbstractController {
                         languageSelectionMenuButton.getItems().add(item);
                     });
 
-        languageVersionUIProperty = DesignerUtil.mapToggleGroupToUserData(languageToggleGroup);
+        languageVersionUIProperty = DesignerUtil.mapToggleGroupToUserData(languageToggleGroup, DesignerUtil::defaultLanguageVersion);
     }
 
 
diff --git a/pmd-ui/src/main/java/net/sourceforge/pmd/util/fxdesigner/XPathPanelController.java b/pmd-ui/src/main/java/net/sourceforge/pmd/util/fxdesigner/XPathPanelController.java
index fdd40208da..ac97483934 100644
--- a/pmd-ui/src/main/java/net/sourceforge/pmd/util/fxdesigner/XPathPanelController.java
+++ b/pmd-ui/src/main/java/net/sourceforge/pmd/util/fxdesigner/XPathPanelController.java
@@ -178,7 +178,7 @@ public class XPathPanelController extends AbstractController {
             xpathVersionMenuButton.getItems().add(item);
         });
 
-        xpathVersionUIProperty = DesignerUtil.mapToggleGroupToUserData(xpathVersionToggleGroup);
+        xpathVersionUIProperty = DesignerUtil.mapToggleGroupToUserData(xpathVersionToggleGroup, DesignerUtil::defaultXPathVersion);
 
         setXpathVersion(XPathRuleQuery.XPATH_2_0);
     }
diff --git a/pmd-ui/src/main/java/net/sourceforge/pmd/util/fxdesigner/util/DesignerUtil.java b/pmd-ui/src/main/java/net/sourceforge/pmd/util/fxdesigner/util/DesignerUtil.java
index 5bcfb5cf15..1f2fbc98ef 100644
--- a/pmd-ui/src/main/java/net/sourceforge/pmd/util/fxdesigner/util/DesignerUtil.java
+++ b/pmd-ui/src/main/java/net/sourceforge/pmd/util/fxdesigner/util/DesignerUtil.java
@@ -21,6 +21,7 @@ import java.util.function.BiFunction;
 import java.util.function.Consumer;
 import java.util.function.Function;
 import java.util.function.Predicate;
+import java.util.function.Supplier;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 import java.util.stream.Collectors;
@@ -44,6 +45,7 @@ import javafx.beans.value.ObservableValue;
 import javafx.collections.ObservableList;
 import javafx.scene.control.ListCell;
 import javafx.scene.control.ListView;
+import javafx.scene.control.Toggle;
 import javafx.scene.control.ToggleGroup;
 import javafx.scene.control.Tooltip;
 import javafx.util.Callback;
@@ -142,19 +144,40 @@ public final class DesignerUtil {
      * maps the selected toggle property to a Var&lt;T>
      */
     @SuppressWarnings("unchecked")
-    public static <T> Var<T> mapToggleGroupToUserData(ToggleGroup toggleGroup) {
+    public static <T> Var<T> mapToggleGroupToUserData(ToggleGroup toggleGroup, Supplier<T> defaultValue) {
         return Var.fromVal(toggleGroup.selectedToggleProperty(), toggleGroup::selectToggle)
                   .mapBidirectional(
                       item -> (T) item.getUserData(),
-                      t -> toggleGroup.getToggles()
-                                      .stream()
-                                      .filter(toggle -> toggle.getUserData().equals(t))
-                                      .findFirst()
-                                      .orElseThrow(() -> new IllegalStateException("Unknown toggle " + t))
+                      t -> selectFirst(
+                          () -> findToggleWithUserData(toggleGroup, t),
+                          () -> findToggleWithUserData(toggleGroup, defaultValue.get())
+                      )
+                          .orElseThrow(() -> new IllegalStateException("Unknown toggle " + t))
                   );
     }
 
 
+    /** Returns the first non-empty optional in the arguments, or else Optional.empty. */
+    @SafeVarargs
+    public static <T> Optional<T> selectFirst(Supplier<Optional<T>>... opts) {
+        for (Supplier<Optional<T>> optGetter : opts) {
+            Optional<T> o = optGetter.get();
+            if (o.isPresent()) {
+                return o;
+            }
+        }
+        return Optional.empty();
+    }
+
+
+    private static <T> Optional<Toggle> findToggleWithUserData(ToggleGroup toggleGroup, T data) {
+        return toggleGroup.getToggles()
+                          .stream()
+                          .filter(toggle -> toggle.getUserData().equals(data))
+                          .findFirst();
+    }
+
+
     public static StringConverter<LanguageVersion> languageVersionStringConverter() {
         return DesignerUtil.stringConverter(LanguageVersion::getShortName,
             s -> LanguageRegistry.findLanguageVersionByTerseName(s.toLowerCase(Locale.ROOT)));