implement field inheritance for crossref-relationships

* based on biblatex inheritance rules (c.f. doc appendix B)
* fixes JabRef#5045

src/main/java/org/jabref/model/entry/BibEntry.java

@@ -32,6 +32,7 @@
 import org.jabref.model.entry.field.StandardField;
 import org.jabref.model.entry.identifier.DOI;
 import org.jabref.model.entry.types.EntryType;
+import org.jabref.model.entry.types.IEEETranEntryType;
 import org.jabref.model.entry.types.StandardEntryType;
 import org.jabref.model.strings.LatexToUnicodeAdapter;
 import org.jabref.model.strings.StringUtil;
@@ -112,6 +113,110 @@ public Optional<String> getResolvedFieldOrAlias(OrFields fields, BibDatabase dat
         return Optional.empty();
     }
 
+    /**
+     * Map an (empty) field of a BibEntry to a field of a cross-referenced entry.
+     *
+     * @param targetField field name of the BibEntry
+     * @param targetEntry type of the BibEntry
+     * @param sourceEntry type of the cross-referenced BibEntry
+     *
+     * @return the mapped field or null if there is no valid mapping available
+     */
+    private Field getSourceField(Field targetField, EntryType targetEntry, EntryType sourceEntry) {
+        //// 1. Sort out forbidden fields
+        if ((targetField == StandardField.IDS) ||
+            (targetField == StandardField.CROSSREF) ||
+            (targetField == StandardField.XREF) ||
+            (targetField == StandardField.ENTRYSET) ||
+            (targetField == StandardField.RELATED) ||
+            (targetField == StandardField.SORTKEY)) {
+            return null;
+        }
+
+        //// 2. Handle special field mappings
+        if ((sourceEntry == StandardEntryType.MvBook && targetEntry == StandardEntryType.InBook) ||
+            (sourceEntry == StandardEntryType.MvBook && targetEntry == StandardEntryType.BookInBook) ||
+            (sourceEntry == StandardEntryType.MvBook && targetEntry == StandardEntryType.SuppBook) ||
+            (sourceEntry == StandardEntryType.Book && targetEntry == StandardEntryType.InBook) ||
+            (sourceEntry == StandardEntryType.Book && targetEntry == StandardEntryType.BookInBook) ||
+            (sourceEntry == StandardEntryType.Book && targetEntry == StandardEntryType.SuppBook)) {
+            if (targetField == StandardField.AUTHOR) { return StandardField.AUTHOR; }
+            if (targetField == StandardField.BOOKAUTHOR) { return StandardField.AUTHOR; }
+        }
+
+        if ((sourceEntry == StandardEntryType.MvBook && targetEntry == StandardEntryType.Book) ||
+            (sourceEntry == StandardEntryType.MvBook && targetEntry == StandardEntryType.InBook) ||
+            (sourceEntry == StandardEntryType.MvBook && targetEntry == StandardEntryType.BookInBook) ||
+            (sourceEntry == StandardEntryType.MvBook && targetEntry == StandardEntryType.SuppBook) ||
+            (sourceEntry == StandardEntryType.MvCollection && targetEntry == StandardEntryType.Collection) ||
+            (sourceEntry == StandardEntryType.MvCollection && targetEntry == StandardEntryType.InCollection) ||
+            (sourceEntry == StandardEntryType.MvCollection && targetEntry == StandardEntryType.SuppCollection) ||
+            (sourceEntry == StandardEntryType.MvProceedings && targetEntry == StandardEntryType.Proceedings) ||
+            (sourceEntry == StandardEntryType.MvProceedings && targetEntry == StandardEntryType.InProceedings) ||
+            (sourceEntry == StandardEntryType.MvReference && targetEntry == StandardEntryType.Reference) ||
+            (sourceEntry == StandardEntryType.MvReference && targetEntry == StandardEntryType.InReference)) {
+            if (targetField == StandardField.MAINTITLE) { return StandardField.TITLE; }
+            if (targetField == StandardField.MAINSUBTITLE) { return StandardField.SUBTITLE; }
+            if (targetField == StandardField.MAINTITLEADDON) { return StandardField.TITLEADDON; }
+
+            // those fields are no more available for the same-name inheritance strategy
+            if ((targetField == StandardField.TITLE) ||
+                (targetField == StandardField.SUBTITLE) ||
+                (targetField == StandardField.TITLEADDON)) {
+                return null;
+            }
+
+            // for these fields, inheritance is not allowed for the specified entry types
+            if ((targetField == StandardField.SHORTTITLE)) {
+                return null;
+            }
+        }
+
+        if ((sourceEntry == StandardEntryType.Book && targetEntry == StandardEntryType.InBook) ||
+            (sourceEntry == StandardEntryType.Book && targetEntry == StandardEntryType.BookInBook) ||
+            (sourceEntry == StandardEntryType.Book && targetEntry == StandardEntryType.SuppBook) ||
+            (sourceEntry == StandardEntryType.Collection && targetEntry == StandardEntryType.InCollection) ||
+            (sourceEntry == StandardEntryType.Collection && targetEntry == StandardEntryType.SuppCollection) ||
+            (sourceEntry == StandardEntryType.Reference && targetEntry == StandardEntryType.InReference) ||
+            (sourceEntry == StandardEntryType.Proceedings && targetEntry == StandardEntryType.InProceedings)) {
+            if (targetField == StandardField.BOOKTITLE) { return StandardField.TITLE; }
+            if (targetField == StandardField.BOOKSUBTITLE) { return StandardField.SUBTITLE; }
+            if (targetField == StandardField.BOOKTITLEADDON) { return StandardField.TITLEADDON; }
+
+            // those fields are no more available for the same-name inheritance strategy
+            if ((targetField == StandardField.TITLE) ||
+                (targetField == StandardField.SUBTITLE) ||
+                (targetField == StandardField.TITLEADDON)) {
+                return null;
+            }
+
+            // for these fields, inheritance is not allowed for the specified entry types
+            if ((targetField == StandardField.SHORTTITLE)) {
+                return null;
+            }
+        }
+
+        if ((sourceEntry == IEEETranEntryType.Periodical && targetEntry == StandardEntryType.Article) ||
+            (sourceEntry == IEEETranEntryType.Periodical && targetEntry == StandardEntryType.SuppPeriodical)) {
+            if (targetField == StandardField.JOURNALTITLE) { return StandardField.TITLE; }
+            if (targetField == StandardField.JOURNALSUBTITLE) { return StandardField.SUBTITLE; }
+
+            // those fields are no more available for the same-name inheritance strategy
+            if ((targetField == StandardField.TITLE) ||
+                (targetField == StandardField.SUBTITLE)) {
+                return null;
+            }
+
+            // for these fields, inheritance is not allowed for the specified entry types
+            if ((targetField == StandardField.SHORTTITLE)) {
+                return null;
+            }
+        }
+
+        //// 3. Fallback to inherit the field with the same name.
+        return targetField;
+    }
+
     /**
      * Returns the text stored in the given field of the given bibtex entry
      * which belongs to the given database.
@@ -137,21 +242,16 @@ public Optional<String> getResolvedFieldOrAlias(Field field, BibDatabase databas
 
         Optional<String> result = getFieldOrAlias(field);
         // If this field is not set, and the entry has a crossref, try to look up the
-        // field in the referred entry: Do not do this for the bibtex key.
-        if (!result.isPresent() && (database != null)) {
+        // field in the referred entry, following the biblatex rules
+        if (result.isEmpty() && (database != null)) {
             Optional<BibEntry> referred = database.getReferencedEntry(this);
             if (referred.isPresent()) {
-                result = referred.get().getFieldOrAlias(field);
-                if (!result.isPresent() && type.equals(StandardEntryType.InProceedings)) {
-                    if (field == StandardField.BOOKTITLE) {
-                        result = referred.get().getFieldOrAlias(StandardField.TITLE);
-                    }
-                    else if (field == StandardField.BOOKSUBTITLE) {
-                        result = referred.get().getFieldOrAlias(StandardField.SUBTITLE);
-                    }
-                    else if (field == StandardField.BOOKAUTHOR) {
-                        result = referred.get().getFieldOrAlias(StandardField.AUTHOR);
-                    }
+                EntryType sourceEntry = referred.get().type.get();
+                EntryType targetEntry = type.get();
+                Field sourceField = getSourceField(field, targetEntry, sourceEntry);
+
+                if (sourceField != null) {
+                    result = referred.get().getFieldOrAlias(sourceField);
                 }
             }
         }