Improve date parsing

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

@@ -8,9 +8,13 @@
 import java.time.LocalDate;
 import java.time.LocalDateTime;
 import java.time.format.DateTimeFormatter;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
 import java.util.Locale;
 import java.util.Optional;
 import java.util.Set;
+import java.util.stream.Collectors;
 
 import javax.swing.JButton;
 import javax.swing.JComboBox;
@@ -41,7 +45,7 @@
 import org.jabref.model.entry.FieldName;
 import org.jabref.model.entry.FieldProperty;
 import org.jabref.model.entry.InternalBibtexFields;
-import org.jabref.model.entry.MonthUtil;
+import org.jabref.model.entry.Month;
 import org.jabref.model.entry.identifier.DOI;
 import org.jabref.model.entry.identifier.ISBN;
 import org.jabref.preferences.JabRefPreferences;
@@ -368,19 +372,19 @@ public static Optional<JComponent> getYesNoExtraComponent(FieldEditor fieldEdito
      * @return
      */
     public static Optional<JComponent> getMonthExtraComponent(FieldEditor fieldEditor, EntryEditor entryEditor, BibDatabaseMode type) {
-        final String[] options = new String[13];
-        options[0] = Localization.lang("Select");
-        for (int i = 1; i <= 12; i++) {
-            options[i] = MonthUtil.getMonthByNumber(i).fullName;
-        }
-        JComboBox<String> month = new JComboBox<>(options);
+        List<String> monthNames = Arrays.stream(Month.values()).map(Month::getFullName).collect(Collectors.toList());
+        List<String> options = new ArrayList<>(13);
+        options.add(Localization.lang("Select"));
+        options.addAll(monthNames);
+
+        JComboBox<String> month = new JComboBox<>(options.toArray(new String[0]));
         month.addActionListener(actionEvent -> {
-            int monthnumber = month.getSelectedIndex();
-            if (monthnumber >= 1) {
+            int monthNumber = month.getSelectedIndex();
+            if (monthNumber >= 1) {
                 if (type == BibDatabaseMode.BIBLATEX) {
-                    fieldEditor.setText(String.valueOf(monthnumber));
+                    fieldEditor.setText(String.valueOf(monthNumber));
                 } else {
-                    fieldEditor.setText(MonthUtil.getMonthByNumber(monthnumber).bibtexFormat);
+                    fieldEditor.setText(Month.getMonthByNumber(monthNumber).get().getBibtexFormat());
                 }
             } else {
                 fieldEditor.setText("");

src/main/java/org/jabref/gui/importer/fetcher/OAI2Fetcher.java

@@ -9,6 +9,7 @@
 import java.nio.charset.StandardCharsets;
 import java.util.Date;
 import java.util.Locale;
+import java.util.Optional;
 
 import javax.swing.JOptionPane;
 import javax.swing.JPanel;
@@ -24,7 +25,7 @@
 import org.jabref.logic.l10n.Localization;
 import org.jabref.model.entry.BibEntry;
 import org.jabref.model.entry.FieldName;
-import org.jabref.model.entry.MonthUtil;
+import org.jabref.model.entry.Month;
 
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
@@ -188,10 +189,8 @@ protected BibEntry importOai2Entry(String key) throws IOException, SAXException
                 entry.setField(FieldName.YEAR, "20" + fixedKey.substring(0, 2));
 
                 int monthNumber = Integer.parseInt(fixedKey.substring(2, 4));
-                MonthUtil.Month month = MonthUtil.getMonthByNumber(monthNumber);
-                if (month.isValid()) {
-                    entry.setField(FieldName.MONTH, month.bibtexFormat);
-                }
+                Optional<Month> month = Month.getMonthByNumber(monthNumber);
+                month.ifPresent(entry::setMonth);
             }
         }
         return entry;

src/main/java/org/jabref/logic/bibtex/comparator/FieldComparator.java

@@ -13,7 +13,7 @@
 import org.jabref.model.entry.FieldName;
 import org.jabref.model.entry.FieldProperty;
 import org.jabref.model.entry.InternalBibtexFields;
-import org.jabref.model.entry.MonthUtil;
+import org.jabref.model.entry.Month;
 import org.jabref.model.metadata.SaveOrderConfig;
 import org.jabref.model.strings.StringUtil;
 
@@ -118,7 +118,9 @@ public int compare(BibEntry e1, BibEntry e2) {
             int comparisonResult = Integer.compare(f1year, f2year);
             return comparisonResult * multiplier;
         } else if (fieldType == FieldType.MONTH) {
-            return Integer.compare(MonthUtil.getMonth(f1).number, MonthUtil.getMonth(f2).number) * multiplier;
+            int month1 = Month.parse(f1).map(Month::getNumber).orElse(-1);
+            int month2 = Month.parse(f2).map(Month::getNumber).orElse(-1);
+            return Integer.compare(month1, month2) * multiplier;
         }
 
         if (isNumeric) {

src/main/java/org/jabref/logic/formatter/bibtexfields/NormalizeDateFormatter.java

@@ -1,14 +1,10 @@
 package org.jabref.logic.formatter.bibtexfields;
 
-import java.time.format.DateTimeFormatter;
-import java.time.format.DateTimeParseException;
-import java.time.temporal.TemporalAccessor;
-import java.util.Arrays;
-import java.util.List;
 import java.util.Optional;
 
 import org.jabref.logic.l10n.Localization;
 import org.jabref.model.cleanup.Formatter;
+import org.jabref.model.entry.Date;
 
 /**
  * This class transforms date to the format yyyy-mm-dd or yyyy-mm..
@@ -34,13 +30,8 @@ public String getKey() {
      */
     @Override
     public String format(String value) {
-        Optional<TemporalAccessor> parsedDate = tryParseDate(value);
-        if (!parsedDate.isPresent()) {
-            return value;
-        }
-
-        DateTimeFormatter dateFormatter = DateTimeFormatter.ofPattern("uuuu-MM[-dd]");
-        return dateFormatter.format(parsedDate.get());
+        Optional<Date> parsedDate = Date.parse(value);
+        return parsedDate.map(Date::getNormalized).orElse(value);
     }
 
     @Override
@@ -53,29 +44,6 @@ public String getExampleInput() {
         return "29.11.2003";
     }
 
-    /*
-     * Try to parse the following formats
-     *  "M/y" (covers 9/15, 9/2015, and 09/2015)
-     *  "MMMM (dd), yyyy" (covers September 1, 2015 and September, 2015)
-     *  "yyyy-MM-dd" (covers 2009-1-15)
-     *  "d.M.uuuu" (covers 15.1.2015)
-     *  "uuuu.M.d" (covers 2015.1.15)
-     * The code is essentially taken from http://stackoverflow.com/questions/4024544/how-to-parse-dates-in-multiple-formats-using-simpledateformat.
-     */
-    private Optional<TemporalAccessor> tryParseDate(String dateString) {
-        List<String> formatStrings = Arrays.asList("uuuu-M-d", "uuuu-M", "M/uu", "M/uuuu", "MMMM d, uuuu", "MMMM, uuuu",
-                "d.M.uuuu", "uuuu.M.d");
-        for (String formatString : formatStrings) {
-            try {
-                return Optional.of(DateTimeFormatter.ofPattern(formatString).parse(dateString));
-            } catch (DateTimeParseException ignored) {
-                // Ignored
-            }
-        }
-
-        return Optional.empty();
-    }
-
     @Override
     public int hashCode() {
         return defaultHashCode();

src/main/java/org/jabref/logic/formatter/bibtexfields/NormalizeMonthFormatter.java

@@ -1,10 +1,11 @@
 package org.jabref.logic.formatter.bibtexfields;
 
 import java.util.Objects;
+import java.util.Optional;
 
 import org.jabref.logic.l10n.Localization;
 import org.jabref.model.cleanup.Formatter;
-import org.jabref.model.entry.MonthUtil;
+import org.jabref.model.entry.Month;
 
 public class NormalizeMonthFormatter implements Formatter {
 
@@ -21,12 +22,8 @@ public String getKey() {
     @Override
     public String format(String value) {
         Objects.requireNonNull(value);
-        MonthUtil.Month month = MonthUtil.getMonth(value);
-        if (month.isValid()) {
-            return month.bibtexFormat;
-        } else {
-            return value;
-        }
+        Optional<Month> month = Month.parse(value);
+        return month.map(Month::getBibtexFormat).orElse(value);
     }
 
     @Override

src/main/java/org/jabref/logic/importer/fetcher/MedlineFetcher.java

@@ -18,6 +18,8 @@
 import javax.xml.stream.XMLStreamException;
 import javax.xml.stream.XMLStreamReader;
 
+import org.jabref.logic.formatter.bibtexfields.ClearFormatter;
+import org.jabref.logic.formatter.bibtexfields.NormalizeMonthFormatter;
 import org.jabref.logic.help.HelpFile;
 import org.jabref.logic.importer.FetcherException;
 import org.jabref.logic.importer.IdBasedParserFetcher;
@@ -26,8 +28,9 @@
 import org.jabref.logic.importer.SearchBasedFetcher;
 import org.jabref.logic.importer.fileformat.MedlineImporter;
 import org.jabref.logic.l10n.Localization;
+import org.jabref.model.cleanup.FieldFormatterCleanup;
 import org.jabref.model.entry.BibEntry;
-import org.jabref.model.entry.MonthUtil;
+import org.jabref.model.entry.FieldName;
 
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
@@ -144,10 +147,11 @@ public Parser getParser() {
 
     @Override
     public void doPostCleanup(BibEntry entry) {
-        entry.clearField("journal-abbreviation");
-        entry.clearField("status");
-        entry.clearField("copyright");
-        entry.getField("month").ifPresent(month -> entry.setField("month", MonthUtil.getMonth(month).bibtexFormat));
+        new FieldFormatterCleanup("journal-abbreviation", new ClearFormatter()).cleanup(entry);
+        new FieldFormatterCleanup("status", new ClearFormatter()).cleanup(entry);
+        new FieldFormatterCleanup("copyright", new ClearFormatter()).cleanup(entry);
+
+        new FieldFormatterCleanup(FieldName.MONTH, new NormalizeMonthFormatter()).cleanup(entry);
     }
 
     @Override

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

@@ -8,6 +8,7 @@
 import java.util.Locale;
 import java.util.Map;
 import java.util.Objects;
+import java.util.Optional;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 
@@ -17,7 +18,7 @@
 import org.jabref.logic.util.FileExtensions;
 import org.jabref.model.entry.BibEntry;
 import org.jabref.model.entry.FieldName;
-import org.jabref.model.entry.MonthUtil;
+import org.jabref.model.entry.Month;
 
 /**
  * Importer for the ISI Web of Science, INSPEC and Medline format.
@@ -338,19 +339,19 @@ public static String parseMonth(String value) {
 
         String[] parts = value.split("\\s|\\-");
         for (String part1 : parts) {
-            MonthUtil.Month month = MonthUtil.getMonthByShortName(part1.toLowerCase(Locale.ROOT));
-            if (month.isValid()) {
-                return month.bibtexFormat;
+            Optional<Month> month = Month.getMonthByShortName(part1.toLowerCase(Locale.ROOT));
+            if (month.isPresent()) {
+                return month.get().getBibtexFormat();
             }
         }
 
         // Try two digit month
         for (String part : parts) {
             try {
                 int number = Integer.parseInt(part);
-                MonthUtil.Month month = MonthUtil.getMonthByNumber(number);
-                if (month.isValid()) {
-                    return month.bibtexFormat;
+                Optional<Month>  month = Month.getMonthByNumber(number);
+                if (month.isPresent()) {
+                    return month.get().getBibtexFormat();
                 }
             } catch (NumberFormatException ignored) {
                 // Ignored

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

@@ -2,14 +2,9 @@
 
 import java.io.BufferedReader;
 import java.io.IOException;
-import java.text.ParseException;
-import java.text.SimpleDateFormat;
 import java.util.ArrayList;
 import java.util.Arrays;
-import java.util.Calendar;
 import java.util.Collection;
-import java.util.Date;
-import java.util.GregorianCalendar;
 import java.util.List;
 import java.util.Objects;
 
@@ -18,6 +13,7 @@
 import org.jabref.logic.importer.ParserResult;
 import org.jabref.logic.util.FileExtensions;
 import org.jabref.model.entry.BibEntry;
+import org.jabref.model.entry.Date;
 import org.jabref.model.entry.FieldName;
 
 import org.apache.commons.logging.Log;
@@ -347,29 +343,14 @@ private void parseAdditionalFields(BibEntry be, boolean multilineUrlFieldAllowed
             } else if ("JEL".equals(keyword)) {
                 be.setField("jel", readMultipleLines(in));
 
-                // parse date field
             } else if (keyword.startsWith("Date")) {
-                Date date = null;
+                // parse date field
                 String content = readMultipleLines(in);
-                String[] recognizedDateFormats = new String[]{"yyyy-MM-dd", "yyyy-MM", "yyyy"};
-                int i = 0;
-                for (; (i < recognizedDateFormats.length) && (date == null); i++) {
-                    try {
-                        date = new SimpleDateFormat(recognizedDateFormats[i]).parse(content);
-                    } catch (ParseException e) {
-                        // wrong format
-                    }
-                }
-
-                Calendar cal = new GregorianCalendar();
-                cal.setTime(date == null ? new Date() : date);
-                be.setField(FieldName.YEAR, String.valueOf(cal.get(Calendar.YEAR)));
-                if ((date != null) && recognizedDateFormats[i - 1].contains("MM")) {
-                    be.setField(FieldName.MONTH, String.valueOf(cal.get(Calendar.MONTH) + 1));
-                }
-                if ((date != null) && recognizedDateFormats[i - 1].contains("dd")) {
-                    be.setField(FieldName.DAY, String.valueOf(cal.get(Calendar.DAY_OF_MONTH)));
-                }
+                Date.parse(content).ifPresent(date -> {
+                    date.getYear().ifPresent(year -> be.setField(FieldName.YEAR, year.toString()));
+                    date.getMonth().ifPresent(month -> be.setField(FieldName.MONTH, month.toString()));
+                    date.getDay().ifPresent(day -> be.setField(FieldName.DAY, day.toString()));
+                });
 
                 // parse URL field
             } else if (keyword.startsWith("URL")) {

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

@@ -17,7 +17,7 @@
 import org.jabref.model.entry.AuthorList;
 import org.jabref.model.entry.BibEntry;
 import org.jabref.model.entry.FieldName;
-import org.jabref.model.entry.MonthUtil;
+import org.jabref.model.entry.Month;
 
 /**
  * Imports a Biblioscape Tag File. The format is described on
@@ -199,10 +199,8 @@ public ParserResult importDatabase(BufferedReader reader) throws IOException {
                         if ((parts.length > 1) && !parts[1].isEmpty()) {
                             try {
                                 int monthNumber = Integer.parseInt(parts[1]);
-                                MonthUtil.Month month = MonthUtil.getMonthByNumber(monthNumber);
-                                if (month.isValid()) {
-                                    fields.put(FieldName.MONTH, month.bibtexFormat);
-                                }
+                                Optional<Month> month = Month.getMonthByNumber(monthNumber);
+                                month.ifPresent(parsedMonth -> fields.put(FieldName.MONTH, parsedMonth.getBibtexFormat()));
                             } catch (NumberFormatException ex) {
                                 // The month part is unparseable, so we ignore it.
                             }

src/main/java/org/jabref/logic/importer/util/JSONEntryParser.java

@@ -2,10 +2,11 @@
 
 import java.util.ArrayList;
 import java.util.List;
+import java.util.Optional;
 
 import org.jabref.model.entry.BibEntry;
 import org.jabref.model.entry.FieldName;
-import org.jabref.model.entry.MonthUtil;
+import org.jabref.model.entry.Month;
 
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
@@ -211,7 +212,8 @@ public static BibEntry parseSpringerJSONtoBibtex(JSONObject springerJsonEntry) {
             entry.setField(FieldName.DATE, date); // For biblatex
             String[] dateparts = date.split("-");
             entry.setField(FieldName.YEAR, dateparts[0]);
-            entry.setField(FieldName.MONTH, MonthUtil.getMonthByNumber(Integer.parseInt(dateparts[1])).bibtexFormat);
+            Optional<Month> month = Month.getMonthByNumber(Integer.parseInt(dateparts[1]));
+            month.ifPresent(entry::setMonth);
         }
 
         // Clean up abstract (often starting with Abstract)