Fix JavaFX thread exception when fetching new infos

src/main/java/org/jabref/gui/BasePanel.java

@@ -203,7 +203,7 @@ public BasePanel(JabRefFrame frame, BasePanelPreferences preferences, BibDatabas
 
         this.getDatabase().registerListener(new UpdateTimestampListener(Globals.prefs));
 
-        this.entryEditor = new EntryEditor(this, preferences.getEntryEditorPreferences(), Globals.getFileUpdateMonitor(), dialogService, externalFileTypes);
+        this.entryEditor = new EntryEditor(this, preferences.getEntryEditorPreferences(), Globals.getFileUpdateMonitor(), dialogService, externalFileTypes, Globals.TASK_EXECUTOR);
 
         this.preview = new PreviewPanel(this, getBibDatabaseContext(), preferences.getKeyBindings(), preferences.getPreviewPreferences(), dialogService, externalFileTypes);
         frame().getGlobalSearchBar().getSearchQueryHighlightObservable().addSearchListener(preview);

src/main/java/org/jabref/gui/entryeditor/EntryEditor.java

@@ -36,10 +36,11 @@
 import org.jabref.gui.help.HelpAction;
 import org.jabref.gui.keyboard.KeyBinding;
 import org.jabref.gui.menus.ChangeEntryTypeMenu;
-import org.jabref.gui.mergeentries.EntryFetchAndMergeWorker;
+import org.jabref.gui.mergeentries.FetchAndMergeEntry;
 import org.jabref.gui.undo.CountingUndoManager;
 import org.jabref.gui.util.ColorUtil;
 import org.jabref.gui.util.DefaultTaskExecutor;
+import org.jabref.gui.util.TaskExecutor;
 import org.jabref.logic.TypedBibEntry;
 import org.jabref.logic.help.HelpFile;
 import org.jabref.logic.importer.EntryBasedFetcher;
@@ -91,14 +92,16 @@ public class EntryEditor extends BorderPane {
     private final EntryEditorPreferences preferences;
     private final DialogService dialogService;
     private final NewDroppedFileHandler fileHandler;
+    private final TaskExecutor taskExecutor;
 
-    public EntryEditor(BasePanel panel, EntryEditorPreferences preferences, FileUpdateMonitor fileMonitor, DialogService dialogService, ExternalFileTypes externalFileTypes) {
+    public EntryEditor(BasePanel panel, EntryEditorPreferences preferences, FileUpdateMonitor fileMonitor, DialogService dialogService, ExternalFileTypes externalFileTypes, TaskExecutor taskExecutor) {
         this.panel = panel;
         this.databaseContext = panel.getBibDatabaseContext();
         this.undoManager = panel.getUndoManager();
         this.preferences = Objects.requireNonNull(preferences);
         this.fileMonitor = fileMonitor;
         this.dialogService = dialogService;
+        this.taskExecutor = taskExecutor;
 
         fileHandler = new NewDroppedFileHandler(dialogService, databaseContext, externalFileTypes,
                 Globals.prefs.getFilePreferences(),
@@ -340,7 +343,7 @@ private void setupToolBar() {
         ContextMenu fetcherMenu = new ContextMenu();
         for (EntryBasedFetcher fetcher : WebFetchers.getEntryBasedFetchers(preferences.getImportFormatPreferences())) {
             MenuItem fetcherMenuItem = new MenuItem(fetcher.getName());
-            fetcherMenuItem.setOnAction(event -> new EntryFetchAndMergeWorker(panel, getEntry(), fetcher).execute());
+            fetcherMenuItem.setOnAction(event -> fetchAndMerge(fetcher));
             fetcherMenu.getItems().add(fetcherMenuItem);
         }
         fetcherButton.setOnMouseClicked(event -> fetcherMenu.show(fetcherButton, Side.RIGHT, 0, 0));
@@ -353,6 +356,10 @@ private void setupToolBar() {
                         generateCiteKeyButton);
     }
 
+    private void fetchAndMerge(EntryBasedFetcher fetcher) {
+        new FetchAndMergeEntry(panel, taskExecutor).fetchAndMerge(entry, fetcher);
+    }
+
     void addSearchListener(SearchQueryHighlightListener listener) {
         // TODO: Highlight search text in entry editors
         searchListeners.add(listener);

src/main/java/org/jabref/gui/fieldeditors/IdentifierEditorViewModel.java

@@ -8,6 +8,7 @@
 import javafx.beans.property.SimpleBooleanProperty;
 import javafx.beans.property.SimpleObjectProperty;
 
+import org.jabref.JabRefGUI;
 import org.jabref.gui.DialogService;
 import org.jabref.gui.autocompleter.AutoCompleteSuggestionProvider;
 import org.jabref.gui.desktop.JabRefDesktop;
@@ -86,8 +87,8 @@ public BooleanProperty identifierLookupInProgressProperty() {
         return identifierLookupInProgress;
     }
 
-    public FetchAndMergeEntry fetchInformationByIdentifier(BibEntry entry) {
-        return new FetchAndMergeEntry(entry, fieldName);
+    public void fetchInformationByIdentifier(BibEntry entry) {
+        new FetchAndMergeEntry(JabRefGUI.getMainFrame().getCurrentBasePanel(), taskExecutor).fetchAndMerge(entry, fieldName);
     }
 
     public void lookupIdentifier(BibEntry entry) {

src/main/java/org/jabref/gui/mergeentries/FetchAndMergeEntry.java

@@ -1,52 +1,93 @@
 package org.jabref.gui.mergeentries;
 
 import java.util.Arrays;
+import java.util.Collections;
 import java.util.List;
+import java.util.Optional;
 
-import org.jabref.JabRefGUI;
+import org.jabref.Globals;
 import org.jabref.gui.BasePanel;
+import org.jabref.gui.DialogService;
+import org.jabref.gui.util.BackgroundTask;
+import org.jabref.gui.util.TaskExecutor;
+import org.jabref.logic.importer.EntryBasedFetcher;
+import org.jabref.logic.importer.IdBasedFetcher;
+import org.jabref.logic.importer.WebFetchers;
 import org.jabref.logic.l10n.Localization;
 import org.jabref.model.entry.BibEntry;
 import org.jabref.model.entry.FieldName;
 
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
 /**
- * Class for fetching and merging information based on a specific field
- *
+ * Class for fetching and merging bibliographic information
  */
 public class FetchAndMergeEntry {
 
     // A list of all field which are supported
     public static List<String> SUPPORTED_FIELDS = Arrays.asList(FieldName.DOI, FieldName.EPRINT, FieldName.ISBN);
+    private static final Logger LOGGER = LoggerFactory.getLogger(FetchAndMergeEntry.class);
+    private final BasePanel panel;
+    private final DialogService dialogService;
+    private final TaskExecutor taskExecutor;
+
+    public FetchAndMergeEntry(BasePanel panel, TaskExecutor taskExecutor) {
+        this.dialogService = panel.frame().getDialogService();
+        this.panel = panel;
+        this.taskExecutor = taskExecutor;
+    }
 
-    /**
-     * Convenience constructor for a single field
-     *
-     * @param entry - BibEntry to fetch information for
-     * @param panel - current BasePanel
-     * @param field - field to get information from
-     */
-    public FetchAndMergeEntry(BibEntry entry, BasePanel panel, String field) {
-        this(entry, panel, Arrays.asList(field));
+    public void fetchAndMerge(BibEntry entry) {
+        fetchAndMerge(entry, SUPPORTED_FIELDS);
     }
 
-    public FetchAndMergeEntry(BibEntry entry, String field) {
-        this(entry, JabRefGUI.getMainFrame().getCurrentBasePanel(), field);
+    public void fetchAndMerge(BibEntry entry, String field) {
+        fetchAndMerge(entry, Collections.singletonList(field));
     }
 
-    /**
-     * Default constructor
-     *
-     * @param entry - BibEntry to fetch information for
-     * @param panel - current BasePanel
-     * @param fields - List of fields to get information from, one at a time in given order
-     */
-    public FetchAndMergeEntry(BibEntry entry, BasePanel panel, List<String> fields) {
+    public void fetchAndMerge(BibEntry entry, List<String> fields) {
         for (String field : fields) {
-            if (entry.hasField(field)) {
-                new FetchAndMergeWorker(panel, entry, field).execute();
+            Optional<String> fieldContent = entry.getField(field);
+            if (fieldContent.isPresent()) {
+                Optional<IdBasedFetcher> fetcher = WebFetchers.getIdBasedFetcherForField(field, Globals.prefs.getImportFormatPreferences());
+                if (fetcher.isPresent()) {
+                    BackgroundTask.wrap(() -> fetcher.get().performSearchById(fieldContent.get()))
+                                  .onSuccess(fetchedEntry -> {
+                                      String type = FieldName.getDisplayName(field);
+                                      if (fetchedEntry.isPresent()) {
+                                          MergeFetchedEntryDialog dialog = new MergeFetchedEntryDialog(panel, entry, fetchedEntry.get(), type);
+                                          dialog.setVisible(true);
+                                      } else {
+                                          panel.frame().setStatus(Localization.lang("Cannot get info based on given %0: %1", type, fieldContent.get()));
+                                      }
+                                  })
+                                  .onFailure(exception -> {
+                                      LOGGER.error("Error while fetching bibliographic information", exception);
+                                      dialogService.showErrorDialogAndWait(exception);
+                                  })
+                                  .executeWith(Globals.TASK_EXECUTOR);
+                }
             } else {
-                panel.frame().setStatus(Localization.lang("No %0 found", FieldName.getDisplayName(field)));
+                dialogService.notify(Localization.lang("No %0 found", FieldName.getDisplayName(field)));
             }
         }
     }
+
+    public void fetchAndMerge(BibEntry entry, EntryBasedFetcher fetcher) {
+        BackgroundTask.wrap(() -> fetcher.performSearch(entry).stream().findFirst())
+                      .onSuccess(fetchedEntry -> {
+                          if (fetchedEntry.isPresent()) {
+                              MergeFetchedEntryDialog dialog = new MergeFetchedEntryDialog(panel, entry, fetchedEntry.get(), fetcher.getName());
+                              dialog.setVisible(true);
+                          } else {
+                              dialogService.notify(Localization.lang("Could not find any bibliographic information."));
+                          }
+                      })
+                      .onFailure(exception -> {
+                          LOGGER.error("Error while fetching entry with " + fetcher.getName(), exception);
+                          dialogService.showErrorDialogAndWait(Localization.lang("Error while fetching from %0", fetcher.getName()), exception);
+                      })
+                      .executeWith(taskExecutor);
+    }
 }

src/main/java/org/jabref/gui/mergeentries/MergeWithFetchedEntryAction.java

@@ -1,5 +1,6 @@
 package org.jabref.gui.mergeentries;
 
+import org.jabref.Globals;
 import org.jabref.gui.BasePanel;
 import org.jabref.gui.DialogService;
 import org.jabref.gui.actions.BaseAction;
@@ -21,7 +22,7 @@ public MergeWithFetchedEntryAction(BasePanel basePanel, DialogService dialogServ
     public void action() {
         if (basePanel.getMainTable().getSelectedEntries().size() == 1) {
             BibEntry originalEntry = basePanel.getMainTable().getSelectedEntries().get(0);
-            new FetchAndMergeEntry(originalEntry, basePanel, FetchAndMergeEntry.SUPPORTED_FIELDS);
+            new FetchAndMergeEntry(basePanel, Globals.TASK_EXECUTOR).fetchAndMerge(originalEntry);
         } else {
             dialogService.showInformationDialogAndWait(Localization.lang("Merge entry with %0 information",
                     FieldName.orFields(FieldName.getDisplayName(FieldName.DOI),