Refactor PDF import

src/main/java/org/jabref/gui/externalfiles/ImportHandler.java

@@ -20,6 +20,7 @@
 import org.jabref.gui.duplicationFinder.DuplicateResolverDialog;
 import org.jabref.gui.fieldeditors.LinkedFileViewModel;
 import org.jabref.gui.libraryproperties.constants.ConstantsItemModel;
+import org.jabref.gui.mergeentries.MultiMergeEntriesView;
 import org.jabref.gui.preferences.GuiPreferences;
 import org.jabref.gui.undo.UndoableInsertEntries;
 import org.jabref.gui.util.DragDrop;
@@ -100,6 +101,7 @@ public ExternalFilesEntryLinker getFileLinker() {
     }
 
     public BackgroundTask<List<ImportFilesResultItemViewModel>> importFilesInBackground(final List<Path> files, final BibDatabaseContext bibDatabaseContext, final FilePreferences filePreferences, TransferMode transferMode) {
+        // TODO: Make a class out of this :)
         return new BackgroundTask<>() {
             private int counter;
             private final List<ImportFilesResultItemViewModel> results = new ArrayList<>();
@@ -128,18 +130,29 @@ public List<ImportFilesResultItemViewModel> call() {
 
                     try {
                         if (FileUtil.isPDFFile(file)) {
-                            ParserResult pdfImporterResult = contentImporter.importPDFContent(file, bibDatabaseContext, filePreferences);
-                            List<BibEntry> pdfEntriesInFile = pdfImporterResult.getDatabase().getEntries();
-
-                            if (pdfImporterResult.hasWarnings()) {
-                                addResultToList(file, false, Localization.lang("Error reading PDF content: %0", pdfImporterResult.getErrorMessage()));
+                            List<BibEntry> pdfEntriesInFile;
+
+                            // See {@link PdfMergeDialog#make} for reason why it is useful to call a merge dialog with
+                            // various {@link PdfBibExtractor}s.
+                            if (files.size() == 1) {
+                                pdfEntriesInFile = new ArrayList<>();
+                                UiTaskExecutor.runAndWaitInJavaFXThread(() -> {
+                                    MultiMergeEntriesView dialog = PdfMergeDialog.make(new BibEntry(), file, preferences, taskExecutor);
+                                    dialogService.showCustomDialogAndWait(dialog).ifPresent(pdfEntriesInFile::add);
+                                });
+                            } else {
+                                ParserResult pdfImporterResult = contentImporter.importPDFContent(file, bibDatabaseContext, filePreferences);
+                                pdfEntriesInFile = pdfImporterResult.getDatabase().getEntries();
+                                if (pdfImporterResult.hasWarnings()) {
+                                    addResultToList(file, false, Localization.lang("Error reading PDF content: %0", pdfImporterResult.getErrorMessage()));
+                                }
                             }
 
                             if (pdfEntriesInFile.isEmpty()) {
                                 entriesToAdd.add(createEmptyEntryWithLink(file));
                                 addResultToList(file, false, Localization.lang("No BibTeX was found. An empty entry was created with file link."));
                             } else {
-                                pdfEntriesInFile.forEach(entry -> {
+                                for (BibEntry entry : pdfEntriesInFile) {
                                     if (entry.getFiles().size() > 1) {
                                         LOGGER.warn("Entry has more than one file attached. This is not supported.");
                                         LOGGER.warn("Entry's files: {}", entry.getFiles());
@@ -150,7 +163,7 @@ public List<ImportFilesResultItemViewModel> call() {
                                     DragDrop.handleDropOfFiles(files, transferMode, fileLinker, entry);
                                     entriesToAdd.addAll(pdfEntriesInFile);
                                     addResultToList(file, true, Localization.lang("File was successfully imported as a new entry"));
-                                });
+                                }
                             }
                         } else if (FileUtil.isBibFile(file)) {
                             var bibtexParserResult = contentImporter.importFromBibFile(file, fileUpdateMonitor);

src/main/java/org/jabref/gui/externalfiles/PdfMergeDialog.java

@@ -0,0 +1,62 @@
+package org.jabref.gui.externalfiles;
+
+import java.io.IOException;
+import java.nio.file.Path;
+import java.util.function.Supplier;
+
+import org.jabref.gui.mergeentries.MultiMergeEntriesView;
+import org.jabref.gui.preferences.GuiPreferences;
+import org.jabref.logic.importer.Importer;
+import org.jabref.logic.importer.ParserResult;
+import org.jabref.logic.importer.fileformat.pdf.PdfContentImporter;
+import org.jabref.logic.importer.fileformat.pdf.PdfEmbeddedBibFileImporter;
+import org.jabref.logic.importer.fileformat.pdf.PdfGrobidImporter;
+import org.jabref.logic.importer.fileformat.pdf.PdfImporter;
+import org.jabref.logic.importer.fileformat.pdf.PdfVerbatimBibtexImporter;
+import org.jabref.logic.importer.fileformat.pdf.PdfXmpImporter;
+import org.jabref.logic.l10n.Localization;
+import org.jabref.logic.util.TaskExecutor;
+import org.jabref.model.entry.BibEntry;
+
+public class PdfMergeDialog {
+    /**
+     * Constructs a merge dialog for a PDF file. This dialog merges results from various {@link PdfImporter}s.
+     * <p>
+     * {@link PdfImporter}s try to extract a {@link BibEntry} out of a PDF file,
+     * but it does not perform this 100% perfectly, it is only a set of heuristics that in some cases might work, in others not.
+     * Thus, JabRef provides this merge dialog that collects the results of all {@link PdfImporter}s
+     * and gives user a choice between field values.
+     */
+    public static MultiMergeEntriesView make(BibEntry entry, Path filePath, GuiPreferences preferences, TaskExecutor taskExecutor) {
+        MultiMergeEntriesView dialog = new MultiMergeEntriesView(preferences, taskExecutor);
+
+        dialog.setTitle(Localization.lang("Merge PDF metadata"));
+
+        dialog.addSource(Localization.lang("Entry"), entry);
+        dialog.addSource(Localization.lang("Verbatim"), wrapImporterToSupplier(new PdfVerbatimBibtexImporter(preferences.getImportFormatPreferences()), filePath));
+        dialog.addSource(Localization.lang("Embedded"), wrapImporterToSupplier(new PdfEmbeddedBibFileImporter(preferences.getImportFormatPreferences()), filePath));
+
+        if (preferences.getGrobidPreferences().isGrobidEnabled()) {
+            dialog.addSource("Grobid", wrapImporterToSupplier(new PdfGrobidImporter(preferences.getImportFormatPreferences()), filePath));
+        }
+
+        dialog.addSource(Localization.lang("XMP metadata"), wrapImporterToSupplier(new PdfXmpImporter(preferences.getXmpPreferences()), filePath));
+        dialog.addSource(Localization.lang("Content"), wrapImporterToSupplier(new PdfContentImporter(), filePath));
+
+        return dialog;
+    }
+
+    private static Supplier<BibEntry> wrapImporterToSupplier(Importer importer, Path filePath) {
+        return () -> {
+            try {
+                ParserResult parserResult = importer.importDatabase(filePath);
+                if (parserResult.isInvalid() || parserResult.isEmpty() || !parserResult.getDatabase().hasEntries()) {
+                    return null;
+                }
+                return parserResult.getDatabase().getEntries().getFirst();
+            } catch (IOException e) {
+                return null;
+            }
+        };
+    }
+}

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

@@ -8,7 +8,6 @@
 import java.util.List;
 import java.util.Optional;
 import java.util.function.BiPredicate;
-import java.util.function.Supplier;
 
 import javafx.beans.Observable;
 import javafx.beans.binding.Bindings;
@@ -23,6 +22,7 @@
 import org.jabref.gui.AbstractViewModel;
 import org.jabref.gui.DialogService;
 import org.jabref.gui.desktop.os.NativeDesktop;
+import org.jabref.gui.externalfiles.PdfMergeDialog;
 import org.jabref.gui.externalfiletype.ExternalFileType;
 import org.jabref.gui.externalfiletype.ExternalFileTypes;
 import org.jabref.gui.icon.IconTheme;
@@ -35,13 +35,6 @@
 import org.jabref.gui.util.ControlHelper;
 import org.jabref.logic.FilePreferences;
 import org.jabref.logic.externalfiles.LinkedFileHandler;
-import org.jabref.logic.importer.Importer;
-import org.jabref.logic.importer.ParserResult;
-import org.jabref.logic.importer.fileformat.PdfContentImporter;
-import org.jabref.logic.importer.fileformat.PdfEmbeddedBibFileImporter;
-import org.jabref.logic.importer.fileformat.PdfGrobidImporter;
-import org.jabref.logic.importer.fileformat.PdfVerbatimBibtexImporter;
-import org.jabref.logic.importer.fileformat.PdfXmpImporter;
 import org.jabref.logic.l10n.Localization;
 import org.jabref.logic.util.TaskExecutor;
 import org.jabref.logic.util.io.FileUtil;
@@ -457,34 +450,11 @@ public ValidationStatus fileExistsValidationStatus() {
 
     public void parsePdfMetadataAndShowMergeDialog() {
         linkedFile.findIn(databaseContext, preferences.getFilePreferences()).ifPresent(filePath -> {
-            MultiMergeEntriesView dialog = new MultiMergeEntriesView(preferences, taskExecutor);
-            dialog.setTitle(Localization.lang("Merge PDF metadata"));
-            dialog.addSource(Localization.lang("Entry"), entry);
-            dialog.addSource(Localization.lang("Verbatim"), wrapImporterToSupplier(new PdfVerbatimBibtexImporter(preferences.getImportFormatPreferences()), filePath));
-            dialog.addSource(Localization.lang("Embedded"), wrapImporterToSupplier(new PdfEmbeddedBibFileImporter(preferences.getImportFormatPreferences()), filePath));
-            if (preferences.getGrobidPreferences().isGrobidEnabled()) {
-                dialog.addSource("Grobid", wrapImporterToSupplier(new PdfGrobidImporter(preferences.getImportFormatPreferences()), filePath));
-            }
-            dialog.addSource(Localization.lang("XMP metadata"), wrapImporterToSupplier(new PdfXmpImporter(preferences.getXmpPreferences()), filePath));
-            dialog.addSource(Localization.lang("Content"), wrapImporterToSupplier(new PdfContentImporter(), filePath));
+            MultiMergeEntriesView dialog = PdfMergeDialog.make(entry, filePath, preferences, taskExecutor);
             dialogService.showCustomDialogAndWait(dialog).ifPresent(newEntry -> {
                 databaseContext.getDatabase().removeEntry(entry);
                 databaseContext.getDatabase().insertEntry(newEntry);
             });
         });
     }
-
-    private Supplier<BibEntry> wrapImporterToSupplier(Importer importer, Path filePath) {
-        return () -> {
-            try {
-                ParserResult parserResult = importer.importDatabase(filePath);
-                if (parserResult.isInvalid() || parserResult.isEmpty() || !parserResult.getDatabase().hasEntries()) {
-                    return null;
-                }
-                return parserResult.getDatabase().getEntries().getFirst();
-            } catch (IOException e) {
-                return null;
-            }
-        };
-    }
 }

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

@@ -23,8 +23,8 @@
 import org.jabref.logic.importer.ImportFormatReader;
 import org.jabref.logic.importer.Importer;
 import org.jabref.logic.importer.ParserResult;
-import org.jabref.logic.importer.fileformat.PdfGrobidImporter;
 import org.jabref.logic.importer.fileformat.PdfMergeMetadataImporter;
+import org.jabref.logic.importer.fileformat.pdf.PdfGrobidImporter;
 import org.jabref.logic.l10n.Localization;
 import org.jabref.logic.preferences.CliPreferences;
 import org.jabref.logic.util.BackgroundTask;
@@ -153,8 +153,7 @@ private ParserResult doImport(List<Path> files, Importer importFormat) throws IO
                     imports.add(importFormatReader.importUnknownFormat(filename, fileUpdateMonitor));
                 } else {
                     UiTaskExecutor.runAndWaitInJavaFXThread(() -> {
-                        if (((importer.get() instanceof PdfGrobidImporter)
-                                || (importer.get() instanceof PdfMergeMetadataImporter))
+                        if (((importer.get() instanceof PdfGrobidImporter) || (importer.get() instanceof PdfMergeMetadataImporter))
                                 && GrobidUseDialogHelper.showAndWaitIfUserIsUndecided(dialogService, preferences.getGrobidPreferences())) {
                             importFormatReader.reset();
                         }

src/main/java/org/jabref/logic/importer/ImportFormatReader.java

@@ -24,14 +24,14 @@
 import org.jabref.logic.importer.fileformat.ModsImporter;
 import org.jabref.logic.importer.fileformat.MsBibImporter;
 import org.jabref.logic.importer.fileformat.OvidImporter;
-import org.jabref.logic.importer.fileformat.PdfContentImporter;
-import org.jabref.logic.importer.fileformat.PdfEmbeddedBibFileImporter;
-import org.jabref.logic.importer.fileformat.PdfGrobidImporter;
 import org.jabref.logic.importer.fileformat.PdfMergeMetadataImporter;
-import org.jabref.logic.importer.fileformat.PdfVerbatimBibtexImporter;
-import org.jabref.logic.importer.fileformat.PdfXmpImporter;
 import org.jabref.logic.importer.fileformat.RepecNepImporter;
 import org.jabref.logic.importer.fileformat.RisImporter;
+import org.jabref.logic.importer.fileformat.pdf.PdfContentImporter;
+import org.jabref.logic.importer.fileformat.pdf.PdfEmbeddedBibFileImporter;
+import org.jabref.logic.importer.fileformat.pdf.PdfGrobidImporter;
+import org.jabref.logic.importer.fileformat.pdf.PdfVerbatimBibtexImporter;
+import org.jabref.logic.importer.fileformat.pdf.PdfXmpImporter;
 import org.jabref.logic.l10n.Localization;
 import org.jabref.model.database.BibDatabases;
 import org.jabref.model.entry.BibEntry;

src/main/java/org/jabref/logic/importer/fileformat/BibliographyFromPdfImporter.java

@@ -19,6 +19,7 @@
 import org.jabref.logic.importer.AuthorListParser;
 import org.jabref.logic.importer.Importer;
 import org.jabref.logic.importer.ParserResult;
+import org.jabref.logic.importer.fileformat.pdf.PdfContentImporter;
 import org.jabref.logic.l10n.Localization;
 import org.jabref.logic.util.FileType;
 import org.jabref.logic.util.StandardFileType;