Table: added undo/redo actions

src/main/java/es/kauron/jstudy/controller/Controller.java

@@ -51,7 +51,7 @@ public class Controller implements Initializable {
     private BorderPane root;
 
     @FXML
-    private MenuItem menuCloseTab, menuSave;
+    private MenuItem menuCloseTab, menuSave, menuUndo, menuRedo;
 
     private final BooleanProperty tabIsTable = new SimpleBooleanProperty(false);
     private final Map<Tab, Initializable> tabMap = new HashMap<>();
@@ -67,9 +67,15 @@ public class Controller implements Initializable {
                 tabIsTable.set(tabMap.get(n) != null);
                 menuCloseTab.setDisable(!n.isClosable());
                 menuSave.disableProperty().unbind();
+                menuUndo.disableProperty().unbind();
+                menuRedo.disableProperty().unbind();
                 menuSave.setDisable(!isTableTab(n) || ((TableController) tabMap.get(n)).saved.get());
                 if (isTableTab(n))
                     menuSave.disableProperty().bind(((TableController) tabMap.get(n)).saved);
+                if (isUndoTab(n)) {
+                    menuUndo.disableProperty().bind(((UndoController) tabMap.get(n)).undoProperty.not());
+                    menuRedo.disableProperty().bind(((UndoController) tabMap.get(n)).redoProperty.not());
+                }
             }
         });
         tabPane.getTabs().removeListener((ListChangeListener<Tab>) c -> theTest = null);
@@ -96,10 +102,26 @@ public class Controller implements Initializable {
         return tabMap.containsKey(tab) && tabMap.get(tab) instanceof TableController;
     }
 
+    private boolean isUndoTab(Tab tab) {
+        return tabMap.containsKey(tab) && tabMap.get(tab) instanceof UndoController;
+    }
+
     private boolean isTestTab(Tab tab) {
         return tabMap.containsKey(tab) && tabMap.get(tab) instanceof TestController;
     }
 
+    @FXML
+    protected void onUndo(ActionEvent event) {
+        Tab tab = tabPane.getSelectionModel().getSelectedItem();
+        if (isUndoTab(tab)) ((UndoController) tabMap.get(tab)).undo();
+    }
+
+    @FXML
+    protected void onRedo(ActionEvent event) {
+        Tab tab = tabPane.getSelectionModel().getSelectedItem();
+        if (isUndoTab(tab)) ((UndoController) tabMap.get(tab)).redo();
+    }
+
     private void checkUpdate() {
         // Check new version via gitlab's REST API
         String newVersion;

src/main/java/es/kauron/jstudy/controller/TableController.java

@@ -11,7 +11,6 @@ import javafx.collections.ObservableList;
 import javafx.collections.transformation.FilteredList;
 import javafx.event.ActionEvent;
 import javafx.fxml.FXML;
-import javafx.fxml.Initializable;
 import javafx.scene.control.*;
 import javafx.scene.input.KeyCode;
 import javafx.scene.input.KeyEvent;
@@ -21,8 +20,10 @@ import javafx.stage.FileChooser;
 import java.io.File;
 import java.net.URL;
 import java.util.*;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
 
-public class TableController implements Initializable {
+public class TableController extends UndoController {
     @FXML
     private TableView<TestItem> table;
     @FXML
@@ -130,14 +131,15 @@ public class TableController implements Initializable {
             newQuestionField.requestFocus();
             return;
         }
+        Action<TestItem> action;
         if (editing.get() == null) {
             TestItem item = new TestItem(newQuestionField.getText().trim(), newAnswerField.getText().trim());
-            data.add(item);
+            action = new AddAction<>(item, data);
             saved.set(false);
         } else {
-            editing.get().answerProperty().set(newAnswerField.getText().trim());
+            action = new EditItemAction(editing.get(), newQuestionField.getText(), newAnswerField.getText());
-            editing.get().questionProperty().set(newQuestionField.getText().trim());
         }
+        doIt(action);
         onCancelAction(event);
     }
 
@@ -162,27 +164,53 @@ public class TableController implements Initializable {
 
     protected void onSwapAction(ActionEvent event) {
         if (table.getSelectionModel().getSelectedIndices().size() > 0) saved.set(false);
+        Collection<Action<TestItem>> actionList = new ArrayList<>();
         for (TestItem item : table.getSelectionModel().getSelectedItems()) {
+            actionList.add(Action.Reversible.genAction(item, () -> {
                 String question = item.getQuestion();
                 item.questionProperty().setValue(item.getAnswer());
                 item.answerProperty().setValue(question);
+            }));
         }
+        doIt(new CollectionAction<>(actionList));
         table.requestFocus();
     }
 
     protected void onDuplicateAction(ActionEvent event) {
         if (table.getSelectionModel().getSelectedIndices().size() > 0) saved.set(false);
+        Collection<Action<TestItem>> actionList = new ArrayList<>();
         for (int i : table.getSelectionModel().getSelectedIndices()) {
             TestItem item = new TestItem(filtered.get(i));
-            item.questionProperty().setValue(item.getQuestion() + " 2");
+            Pattern p = Pattern.compile("^(.*) (\\d*)$");
-            data.add(item);
+            String base = item.getQuestion();
+            int n = 2;
+            Matcher m = p.matcher(base);
+            if (m.find()) {
+                n = Integer.parseInt(m.group(2)) + 1;
+                base = m.group(1);
             }
+            while (isAQuestion(base + " " + n))
+                n++;
+            item.questionProperty().setValue(base + " " + n);
+            actionList.add(new AddAction<>(item, data));
+        }
+        doIt(new CollectionAction<>(actionList));
         table.requestFocus();
     }
 
+    private boolean isAQuestion(String q) {
+        for (TestItem t : data)
+            if (t.getQuestion().equals(q))
+                return true;
+        return false;
+    }
+
     protected void onDeleteAction(ActionEvent event) {
         if (table.getSelectionModel().getSelectedIndices().size() > 0) saved.set(false);
-        data.removeAll(table.getSelectionModel().getSelectedItems());
+        Collection<Action<TestItem>> actionList = new ArrayList<>();
+        for (TestItem i : table.getSelectionModel().getSelectedItems())
+            actionList.add(Action.invert(new AddAction<>(i, data, data.indexOf(i))));
+        doIt(new CollectionAction<>(actionList));
         table.requestFocus();
     }
 

src/main/java/es/kauron/jstudy/controller/UndoController.java

@@ -0,0 +1,164 @@
+package es.kauron.jstudy.controller;
+
+import es.kauron.jstudy.model.TestItem;
+import javafx.beans.property.BooleanProperty;
+import javafx.beans.property.SimpleBooleanProperty;
+import javafx.fxml.Initializable;
+
+import java.util.Collection;
+import java.util.List;
+import java.util.Stack;
+
+public abstract class UndoController implements Initializable {
+    private Stack<Action<?>> undoStack = new Stack<>();
+    private Stack<Action<?>> redoStack = new Stack<>();
+    public BooleanProperty undoProperty = new SimpleBooleanProperty(false);
+    public BooleanProperty redoProperty = new SimpleBooleanProperty(false);
+
+    public void doIt(Action<?> action) {
+        action.action();
+        redoStack.clear();
+        redoProperty.set(false);
+        if (undoStack.empty()) undoProperty.set(true);
+        undoStack.push(action);
+        undoProperty.set(true);
+    }
+
+    public void undo() {
+        Action<?> a = undoStack.pop();
+        a.reverse();
+        if (undoStack.empty())
+            undoProperty.set(false);
+        if (redoStack.empty())
+            redoProperty.set(true);
+        redoStack.push(a);
+    }
+
+    public void redo() {
+        Action<?> a = redoStack.pop();
+        a.action();
+        if (redoStack.empty())
+            redoProperty.set(false);
+        if (undoStack.empty())
+            undoProperty.set(true);
+        undoStack.push(a);
+    }
+
+    public interface Call {
+        void call();
+    }
+
+    public abstract static class Action<A> {
+        protected final A item;
+
+        public Action(A item) {
+            this.item = item;
+        }
+
+        public abstract void action();
+        public abstract void reverse();
+
+        public static <X> Action<X> invert(Action<X> action) {
+            return new Action<X>(action.item) {
+                @Override
+                public void action() {
+                    action.reverse();
+                }
+
+                @Override
+                public void reverse() {
+                    action.action();
+                }
+            };
+        }
+
+        public static <E> Action<E> genAction(E item, Call doit, Call undoit) {
+            return new Action<E>(item) {
+                @Override
+                public void action() { doit.call(); }
+                @Override
+                public void reverse() { undoit.call(); }
+            };
+        }
+
+        public abstract static class Reversible<R> extends Action<R> {
+            public Reversible(R item) {
+                super(item);
+            }
+
+            @Override
+            public void reverse() {
+                action();
+            }
+
+            public static <R> Action<R> genAction(R item, Call doit) {
+                return new Reversible<R>(item) {
+                    @Override
+                    public void action() { doit.call(); }
+                };
+            }
+        }
+    }
+
+    public static class AddAction<N> extends Action<N> {
+        private final List<N> list;
+        private final int index;
+
+        public AddAction(N item, List<N> list) {
+            this(item, list, list.size());
+        }
+
+        public AddAction(N item, List<N> list, int index) {
+            super(item);
+            this.list = list;
+            this.index = index;
+        }
+
+        @Override
+        public void action() {
+            list.add(index, item);
+        }
+
+        @Override
+        public void reverse() {
+            list.remove(item);
+        }
+    }
+
+    public static class CollectionAction<N> extends Action<Collection<Action<N>>> {
+        public CollectionAction(Collection<Action<N>> item) {
+            super(item);
+        }
+
+        @Override
+        public void action() {
+            for (Action<N> a : item)
+                a.action();
+        }
+
+        @Override
+        public void reverse() {
+            for (Action<N> a : item)
+                a.reverse();
+        }
+    }
+
+    public static class EditItemAction extends Action.Reversible<TestItem> {
+        private String question, answer;
+        public EditItemAction(TestItem item, String newQuestion, String newAnswer) {
+            super(item);
+            this.question = newQuestion;
+            this.answer   = newAnswer;
+        }
+
+        @Override
+        public void action() {
+            String q = item.getQuestion();
+            String a = item.getAnswer();
+            item.questionProperty().setValue(question);
+            item.answerProperty().setValue(answer);
+            question = q;
+            answer = a;
+        }
+    }
+}

src/main/resources/es/kauron/jstudy/view/main.fxml

@@ -148,6 +148,20 @@
             </MenuItem>
           </items>
         </Menu>
+        <Menu text="_Edit">
+          <items>
+            <MenuItem onAction="#onUndo" fx:id="menuUndo" disable="true" text="_Undo">
+              <accelerator>
+                <KeyCodeCombination control="DOWN" code="Z" shortcut="UP" shift="UP" meta="UP" alt="UP" />
+              </accelerator>
+            </MenuItem>
+            <MenuItem onAction="#onRedo" fx:id="menuRedo" disable="true" text="_Redo">
+              <accelerator>
+                <KeyCodeCombination control="DOWN" code="Y" shortcut="UP" shift="UP" meta="UP" alt="UP" />
+              </accelerator>
+            </MenuItem>
+          </items>
+        </Menu>
       </menus>
     </MenuBar>
   </top>