Paying off technical debt: almost all utility classes have a private …

…constructor now. (#2649)

* Start paying technical debt.

* Continue adding private constructors.

* Add more private constructors.

* Continue adding private constructors.

* Continue adding private constructors.

* Remove unused private method.

src/main/java/org/jabref/Globals.java

@@ -49,6 +49,9 @@ public class Globals {
     private static GlobalFocusListener focusListener;
     private static FileUpdateMonitor fileUpdateMonitor;
 
+    private Globals() {
+    }
+
     // Key binding preferences
     public static KeyBindingPreferences getKeyPrefs() {
         if (keyPrefs == null) {

src/main/java/org/jabref/cli/CrossrefFetcherEvaluator.java

@@ -25,6 +25,9 @@
  */
 public class CrossrefFetcherEvaluator {
 
+    private CrossrefFetcherEvaluator() {
+    }
+
     public static void main(String[] args) throws IOException, InterruptedException {
         Globals.prefs = JabRefPreferences.getInstance();
         try (FileReader reader = new FileReader(args[0])) {

src/main/java/org/jabref/cli/GenerateCharacterTable.java

@@ -7,6 +7,9 @@
 
 public class GenerateCharacterTable {
 
+    private GenerateCharacterTable() {
+    }
+
     public static void main(String[] args) {
         Map<Integer, String> characterMap = new TreeMap<>(HTMLUnicodeConversionMaps.NUMERICAL_LATEX_CONVERSION_MAP);
         System.out.println("\\documentclass[10pt, a4paper]{article}");

src/main/java/org/jabref/cli/XMPUtilMain.java

@@ -28,6 +28,9 @@
 
 public class XMPUtilMain {
 
+    private XMPUtilMain() {
+    }
+
     /**
      * Command-line tool for working with XMP-data.
      *

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

@@ -21,6 +21,8 @@ public class EntryMarker {
 
     private static final Pattern MARK_NUMBER_PATTERN = Pattern.compile(JabRefPreferences.getInstance().MARKING_WITH_NUMBER_PATTERN);
 
+    private EntryMarker() {
+    }
 
     /**
      * @param increment whether the given increment should be added to the current one. Currently never used in JabRef. Could be used to increase marking color ("Mark in specific color").

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

@@ -47,6 +47,9 @@ public class GUIGlobals {
 
     public static final int MAX_BACK_HISTORY_SIZE = 10; // The maximum number of "Back" operations stored.
 
+    private GUIGlobals() {
+    }
+
     public static JLabel getTableIcon(String fieldType) {
         JLabel label = GUIGlobals.TABLE_ICONS.get(fieldType);
         if (label == null) {

src/main/java/org/jabref/gui/actions/Actions.java

@@ -69,4 +69,7 @@ public class Actions {
     public static final String UNMARK_ENTRIES = "unmarkEntries";
     public static final String WRITE_XMP = "writeXMP";
     public static final String PRINT_PREVIEW = "printPreview";
+
+    private Actions() {
+    }
 }

src/main/java/org/jabref/gui/autosaveandbackup/BackupUIManager.java

@@ -13,6 +13,9 @@
  */
 public class BackupUIManager {
 
+    private BackupUIManager() {
+    }
+
     public static void showRestoreBackupDialog(JFrame frame, Path originalPath) {
         int answer = JOptionPane.showConfirmDialog(frame,
                 new StringBuilder()

src/main/java/org/jabref/gui/customentrytypes/CustomEntryTypesManager.java

@@ -10,6 +10,9 @@
 
 public class CustomEntryTypesManager {
 
+    private CustomEntryTypesManager() {
+    }
+
     /**
      * Iterate through all entry types, and store those that are
      * custom defined to preferences. This method is called from

src/main/java/org/jabref/gui/desktop/JabRefDesktop.java

@@ -52,6 +52,9 @@ public class JabRefDesktop {
     private static final NativeDesktop NATIVE_DESKTOP = getNativeDesktop();
     private static final Pattern REMOTE_LINK_PATTERN = Pattern.compile("[a-z]+://.*");
 
+    private JabRefDesktop() {
+    }
+
     /**
      * Open a http/pdf/ps viewer for the given link string.
      */

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

@@ -117,7 +117,7 @@ private void registerHyperlinkListener() {
         this.addHyperlinkListener(e -> {
             try {
                 if ((e.getURL() != null) && (e.getEventType() == HyperlinkEvent.EventType.ACTIVATED)) {
-                        new JabRefDesktop().openBrowser(e.getURL().toString());
+                    JabRefDesktop.openBrowser(e.getURL().toString());
                     }
                 } catch (IOException e1) {
                     LOGGER.error(e1.getMessage(), e1);

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

@@ -51,6 +51,10 @@
 
 public class FieldExtraComponents {
 
+
+    private FieldExtraComponents() {
+    }
+
     private static final Log LOGGER = LogFactory.getLog(FieldExtraComponents.class);
 
     private static final String ABBREVIATION_TOOLTIP_TEXT = "<HTML>"

src/main/java/org/jabref/gui/exporter/ExportAction.java

@@ -33,6 +33,9 @@ public class ExportAction {
 
     private static final Log LOGGER = LogFactory.getLog(ExportAction.class);
 
+    private ExportAction() {
+    }
+
 
     /**
      * Create an AbstractAction for performing an export operation.

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

@@ -39,6 +39,9 @@
 
 public class AutoSetLinks {
 
+    private AutoSetLinks() {
+    }
+
     /**
      * Shortcut method if links are set without using the GUI
      *

src/main/java/org/jabref/gui/groups/GroupDescriptions.java

@@ -8,6 +8,9 @@
 
 public class GroupDescriptions {
 
+    private GroupDescriptions() {
+    }
+
     public static String getDescriptionForPreview(String field, String expr, boolean caseSensitive, boolean regExp) {
         String header = regExp ? Localization.lang(
                 "This group contains entries whose <b>%0</b> field contains the regular expression <b>%1</b>",

src/main/java/org/jabref/gui/groups/UndoableChangeEntriesOfGroup.java

@@ -11,18 +11,20 @@
 
 public class UndoableChangeEntriesOfGroup {
 
-    public static AbstractUndoableEdit getUndoableEdit(GroupTreeNodeViewModel node, List<FieldChange> changes) {
-        boolean hasEntryChanges = false;
-        NamedCompound entryChangeCompound = new NamedCompound(Localization.lang("change entries of group"));
-        for (FieldChange fieldChange : changes) {
-            hasEntryChanges = true;
-            entryChangeCompound.addEdit(new UndoableFieldChange(fieldChange));
-        }
-        if (hasEntryChanges) {
-            entryChangeCompound.end();
-            return entryChangeCompound;
-        }
+    private UndoableChangeEntriesOfGroup() {
+    }
 
-        return null;
+   public static AbstractUndoableEdit getUndoableEdit(GroupTreeNodeViewModel node, List<FieldChange> changes) {
+       boolean hasEntryChanges = false;
+       NamedCompound entryChangeCompound = new NamedCompound(Localization.lang("change entries of group"));
+       for(FieldChange fieldChange : changes) {
+           hasEntryChanges = true;
+           entryChangeCompound.addEdit(new UndoableFieldChange(fieldChange));
+       }
+       if (hasEntryChanges) {
+           entryChangeCompound.end();
+           return entryChangeCompound;
+       }
+       return null;
     }
 }

src/main/java/org/jabref/gui/groups/WarnAssignmentSideEffects.java

@@ -16,6 +16,9 @@
 
 public class WarnAssignmentSideEffects {
 
+    private WarnAssignmentSideEffects() {
+    }
+
     /**
      * Warns the user of undesired side effects of an explicit assignment/removal of entries to/from this group.
      * Currently there are four types of groups: AllEntriesGroup, SearchGroup - do not support explicit assignment.

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

@@ -12,6 +12,9 @@
 
 class ImportFileFilter {
 
+    private ImportFileFilter() {
+    }
+
     public static FileChooser.ExtensionFilter convert(Importer format) {
         return new FileChooser.ExtensionFilter(format.getExtensions().getDescription(),
                 format.getExtensions().getExtensions());

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

@@ -32,6 +32,9 @@
 public class ImportFormats {
     private static final Log LOGGER = LogFactory.getLog(ImportFormats.class);
 
+    private ImportFormats() {
+    }
+
     /**
      * Create an AbstractAction for performing an Import operation.
      * @param frame The JabRefFrame of this JabRef instance.

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

@@ -18,6 +18,9 @@
  */
 public class ParserResultWarningDialog {
 
+    private ParserResultWarningDialog() {
+    }
+
     /**
      * Shows a dialog with the warnings from an import or open of a file
      *

src/main/java/org/jabref/gui/journals/JournalAbbreviationsUtil.java

@@ -10,6 +10,9 @@
 
 public class JournalAbbreviationsUtil {
 
+    private JournalAbbreviationsUtil() {
+    }
+
     public static TableModel getTableModel(Collection<Abbreviation> abbreviations) {
         Object[][] cells = new Object[abbreviations.size()][2];
         int row = 0;

src/main/java/org/jabref/gui/keyboard/EmacsKeyBindings.java

@@ -188,6 +188,9 @@ public class EmacsKeyBindings {
             new JEditorPane(),
     };
 
+    private EmacsKeyBindings() {
+    }
+
     /**
      * Loads the emacs keybindings for all common <code>JTextComponent</code>s.
      *

src/main/java/org/jabref/gui/keyboard/KeyBinder.java

@@ -10,6 +10,9 @@
 
 public class KeyBinder {
 
+    private KeyBinder() {
+    }
+
     /**
      * Binds ESC-Key to cancel button
      *

src/main/java/org/jabref/gui/maintable/MainTableNameFormatter.java

@@ -6,6 +6,8 @@
 
 public class MainTableNameFormatter {
 
+    private MainTableNameFormatter(){}
+
     /**
      * Format a name field for the table, according to user preferences.
      *

src/main/java/org/jabref/gui/search/JTextFieldChangeListenerUtil.java

@@ -19,6 +19,9 @@
  */
 public class JTextFieldChangeListenerUtil {
 
+    private JTextFieldChangeListenerUtil() {
+    }
+
     /**
      * Installs a listener to receive notification when the text of any
      * {@code JTextComponent} is changed. Internally, it installs a

src/main/java/org/jabref/gui/specialfields/SpecialFieldDropDown.java

@@ -21,6 +21,9 @@
 
 public class SpecialFieldDropDown {
 
+    private SpecialFieldDropDown() {
+    }
+
     public static JButton generateSpecialFieldButtonWithDropDown(SpecialField field, JabRefFrame frame) {
         Dimension buttonDim = new Dimension(23, 23);
         SpecialFieldViewModel viewModel = new SpecialFieldViewModel(field);

src/main/java/org/jabref/gui/util/BindingsHelper.java

@@ -16,6 +16,10 @@
  * Some methods are taken from https://bugs.openjdk.java.net/browse/JDK-8134679
  */
 public class BindingsHelper {
+
+    private BindingsHelper() {
+    }
+
     public static <T> BooleanBinding any(ObservableList<T> source, Predicate<T> predicate) {
         return Bindings.createBooleanBinding(() -> source.stream().anyMatch(predicate), source);
     }

src/main/java/org/jabref/logic/bibtexkeypattern/BibtexKeyPatternUtil.java

@@ -45,6 +45,9 @@ public class BibtexKeyPatternUtil {
 
     private static final int CHARS_OF_FIRST = 5;
 
+    private BibtexKeyPatternUtil() {
+    }
+
     private static String normalize(String content) {
         List<String> tokens = new ArrayList<>();
         int b = 0;

src/main/java/org/jabref/logic/bst/BibtexNameFormatter.java

@@ -26,6 +26,9 @@
  */
 public class BibtexNameFormatter {
 
+    private BibtexNameFormatter() {
+    }
+
     public static String formatName(String authorsNameList, int whichName, String formatString, Warn warn) {
         AuthorList al = AuthorList.parse(authorsNameList);
 

src/main/java/org/jabref/logic/bst/BibtexPurify.java

@@ -12,6 +12,9 @@
  */
 public class BibtexPurify {
 
+    private BibtexPurify() {
+    }
+
     /**
      *
      * @param toPurify

src/main/java/org/jabref/logic/bst/BibtexTextPrefix.java

@@ -16,6 +16,9 @@
  */
 public class BibtexTextPrefix {
 
+    private BibtexTextPrefix() {
+    }
+
     /**
      *
      * @param numOfChars

src/main/java/org/jabref/logic/bst/BibtexWidth.java

@@ -29,7 +29,6 @@ public class BibtexWidth {
 
     private static int[] widths;
 
-
     static {
         if (BibtexWidth.widths == null) {
             BibtexWidth.widths = new int[128];
@@ -135,6 +134,9 @@ public class BibtexWidth {
         }
     }
 
+    private BibtexWidth() {
+    }
+
     private static int getSpecialCharWidth(char[] c, int pos) {
         if ((pos + 1) < c.length) {
             if ((c[pos] == 'o') && (c[pos + 1] == 'e')) {

src/main/java/org/jabref/logic/citationstyle/CitationStyleGenerator.java

@@ -29,6 +29,9 @@ public class CitationStyleGenerator {
     private static final Log LOGGER = LogFactory.getLog(CitationStyleGenerator.class);
     private static final BibTeXConverter BIBTEX_CONVERTER = new BibTeXConverter();
 
+    private CitationStyleGenerator() {
+    }
+
     /**
      * WARNING: the citation is generated using JavaScript which may take some time, better call it from outside the main Thread
      * Generates a Citation based on the given entry and style

src/main/java/org/jabref/logic/cleanup/Cleanups.java

@@ -56,6 +56,9 @@ public class Cleanups {
         RECOMMEND_BIBLATEX_ACTIONS = new FieldFormatterCleanups(false, recommendedBiblatexFormatters);
     }
 
+    private Cleanups() {
+    }
+
     public static List<Formatter> getAvailableFormatters() {
         return Collections.unmodifiableList(availableFormatters);
     }

src/main/java/org/jabref/logic/exporter/ExportFormats.java

@@ -15,6 +15,8 @@ public class ExportFormats {
     // Global variable that is used for counting output entries when exporting:
     public static int entryNumber;
 
+    private ExportFormats() {
+    }
 
     public static void initAllExports(Map<String, ExportFormat> customFormats,
             LayoutFormatterPreferences layoutPreferences, SavePreferences savePreferences) {

src/main/java/org/jabref/logic/exporter/MetaDataSerializer.java

@@ -18,6 +18,9 @@
 
 public class MetaDataSerializer {
 
+    private MetaDataSerializer() {
+    }
+
     /**
      * Writes all data in the format <key, serialized data>.
      */
@@ -90,7 +93,7 @@ private static Map<String, List<String>> serializeCiteKeyPattern(MetaData metaDa
                 stringyPattern.put(metaDataKey, data);
             }
         }
-        if (citeKeyPattern.getDefaultValue() != null && !citeKeyPattern.getDefaultValue().isEmpty()) {
+        if ((citeKeyPattern.getDefaultValue() != null) && !citeKeyPattern.getDefaultValue().isEmpty()) {
             List<String> data = new ArrayList<>();
             data.add(citeKeyPattern.getDefaultValue().get(0));
             stringyPattern.put(MetaData.KEYPATTERNDEFAULT, data);