Fix #13269 : support multi-file import across different formats (#13271)

* fix: multi-file imports

* remove comment

* add null check before accessing tab database context

* fix NPE when importing into current library if no library tab is open

* added support for multi-file import through the 'Import into current/new library' dialog

* remove extra blank line

* update FileDialogConfiguration with selected extension filter after multi-file selection

* fix importer format detection

* add comment to explain tab nullcheck

Author: 070jhz

CHANGELOG.md

@@ -36,6 +36,7 @@ Note that this project **does not** adhere to [Semantic Versioning](https://semv
 - We added a new `jabkit` command `pseudonymize` to pseudonymize the library. [#13109](https://github.com/JabRef/jabref/issues/13109)
 - We added functionality to focus running instance when trying to start a second instance. [#13129](https://github.com/JabRef/jabref/issues/13129)
 - We added a new setting in the 'Entry Editor' preferences to hide the 'File Annotations' tab when no annotations are available. [#13143](https://github.com/JabRef/jabref/issues/13143)
+- We added support for multi-file import across different formats. [#13269](https://github.com/JabRef/jabref/issues/13269)
 
 ### Changed
 

jabgui/src/main/java/org/jabref/gui/JabRefDialogService.java

@@ -462,6 +462,7 @@ public Optional<Path> showDirectorySelectionDialog(DirectoryDialogConfiguration
     public List<Path> showFileOpenDialogAndGetMultipleFiles(FileDialogConfiguration fileDialogConfiguration) {
         FileChooser chooser = getConfiguredFileChooser(fileDialogConfiguration);
         List<File> files = chooser.showOpenMultipleDialog(mainWindow);
+        Optional.ofNullable(chooser.getSelectedExtensionFilter()).ifPresent(fileDialogConfiguration::setSelectedExtensionFilter);
         return files != null ? files.stream().map(File::toPath).toList() : List.of();
     }
 

jabgui/src/main/java/org/jabref/gui/importer/ImportCommand.java

@@ -11,6 +11,7 @@
 import javafx.stage.FileChooser;
 
 import org.jabref.gui.DialogService;
+import org.jabref.gui.LibraryTab;
 import org.jabref.gui.LibraryTabContainer;
 import org.jabref.gui.StateManager;
 import org.jabref.gui.actions.SimpleCommand;
@@ -89,27 +90,50 @@ public void execute() {
                 .addExtensionFilter(FileFilterConverter.importerToExtensionFilter(importers))
                 .withInitialDirectory(preferences.getImporterPreferences().getImportWorkingDirectory())
                 .build();
-        dialogService.showFileOpenDialog(fileDialogConfiguration)
-                     .ifPresent(path -> importSingleFile(path, importers, fileDialogConfiguration.getSelectedExtensionFilter()));
-    }
 
-    private void importSingleFile(Path file, SortedSet<Importer> importers, FileChooser.ExtensionFilter selectedExtensionFilter) {
-        if (!Files.exists(file)) {
-            dialogService.showErrorDialogAndWait(Localization.lang("Import"),
-                    Localization.lang("File not found") + ": '" + file.getFileName() + "'.");
+        List<Path> selectedFiles = dialogService.showFileOpenDialogAndGetMultipleFiles(fileDialogConfiguration);
+
+        if (selectedFiles.isEmpty()) {
+            return; // User cancelled or no files selected
+        }
+
+        importMultipleFiles(selectedFiles, importers, fileDialogConfiguration.getSelectedExtensionFilter());
+    }
 
-            return;
+    private void importMultipleFiles(List<Path> files, SortedSet<Importer> importers, FileChooser.ExtensionFilter selectedExtensionFilter) {
+        for (Path file : files) {
+            if (!Files.exists(file)) {
+                dialogService.showErrorDialogAndWait(Localization.lang("Import"),
+                        Localization.lang("File not found") + ": '" + file.getFileName() + "'.");
+                return;
+            }
         }
 
-        if (selectedExtensionFilter == FileFilterConverter.ANY_FILE || "Available import formats".equals(selectedExtensionFilter.getDescription())) {
-            selectedExtensionFilter = FileFilterConverter.determineExtensionFilter(file);
+        BackgroundTask<ParserResult> task;
+        Optional<Importer> format;
+
+        boolean isGeneralFilter = selectedExtensionFilter == FileFilterConverter.ANY_FILE
+                || "Available import formats".equals(selectedExtensionFilter.getDescription());
+
+        if (!isGeneralFilter) {
+            // User picked a specific format
+            format = FileFilterConverter.getImporter(selectedExtensionFilter, importers);
+        } else if (files.size() == 1) {
+            // Infer if only one file and no specific filter
+            selectedExtensionFilter = FileFilterConverter.determineExtensionFilter(files.getFirst());
+            format = FileFilterConverter.getImporter(selectedExtensionFilter, importers);
+        } else {
+            format = Optional.empty();
         }
 
-        Optional<Importer> format = FileFilterConverter.getImporter(selectedExtensionFilter, importers);
-        BackgroundTask<ParserResult> task = BackgroundTask.wrap(
-                () -> doImport(List.of(file), format.orElse(null)));
+        task = BackgroundTask.wrap(() -> doImport(files, format.orElse(null)));
+
+        LibraryTab tab = tabContainer.getCurrentLibraryTab();
 
-        if (importMethod == ImportMethod.AS_NEW) {
+        // If there is no open library tab, we fall back to importing as new
+        // This prevents a crash in case the user selects "Import into current library"
+        // while no library is currently open.
+        if (importMethod == ImportMethod.AS_NEW || tab == null) {
             task.onSuccess(parserResult -> {
                     tabContainer.addTab(parserResult.getDatabaseContext(), true);
                     dialogService.notify(Localization.lang("%0 entry(s) imported", parserResult.getDatabase().getEntries().size()));
@@ -120,13 +144,13 @@ private void importSingleFile(Path file, SortedSet<Importer> importers, FileChoo
                 })
                 .executeWith(taskExecutor);
         } else {
-            ImportEntriesDialog dialog = new ImportEntriesDialog(tabContainer.getCurrentLibraryTab().getBibDatabaseContext(), task);
+            ImportEntriesDialog dialog = new ImportEntriesDialog(tab.getBibDatabaseContext(), task);
             dialog.setTitle(Localization.lang("Import"));
             dialogService.showCustomDialogAndWait(dialog);
         }
 
         // Set last working dir for import
-        preferences.getImporterPreferences().setImportWorkingDirectory(file.getParent());
+        preferences.getImporterPreferences().setImportWorkingDirectory(files.getLast().getParent());
     }
 
     /**