Improve matching of DOIs (#13487)

* Improve matching of DOIs

* Add link to PR

* Fix if branches

Author: koppor

CHANGELOG.md

@@ -43,6 +43,7 @@ Note that this project **does not** adhere to [Semantic Versioning](https://semv
 - We added a highlighted diff regarding changes to the Group Tree Structure of a bib file, made outside JabRef. [#11221](https://github.com/JabRef/jabref/issues/11221)
 - 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)
+- We improved the detection of DOIs on the first page of a PDF. [#13487](https://github.com/JabRef/jabref/pull/13487)
 - We added support for dark title bar on Windows. [#11457](https://github.com/JabRef/jabref/issues/11457)
 - We moved some functionality from the graphical application `jabref` with new command verbs `generate-citation-keys`, `check-consistency`, `fetch`, `search`, `convert`, `generate-bib-from-aux`, `preferences` and `pdf` to the new toolkit. [#13012](https://github.com/JabRef/jabref/pull/13012) [#110](https://github.com/JabRef/jabref/issues/110)
 - We merged the 'New Entry', 'Import by ID', and 'New Entry from Plain Text' tools into a single 'Create New Entry' tool. [#8808](https://github.com/JabRef/jabref/issues/8808)

jablib/src/main/java/org/jabref/logic/importer/fileformat/pdf/PdfContentImporter.java

@@ -31,6 +31,7 @@
 import org.apache.pdfbox.pdmodel.PDDocument;
 import org.apache.pdfbox.text.PDFTextStripper;
 import org.apache.pdfbox.text.TextPosition;
+import org.jspecify.annotations.Nullable;
 
 import static org.jabref.model.strings.StringUtil.isNullOrEmpty;
 
@@ -576,18 +577,12 @@ Optional<BibEntry> getEntryFromPDFContent(String firstpageContents, String lineS
         return Optional.of(entry);
     }
 
-    private String getDoi(String doi) {
-        int pos;
-        if (doi == null) {
-            pos = curString.indexOf("DOI");
-            if (pos < 0) {
-                pos = curString.indexOf(StandardField.DOI.getName());
-            }
-            if (pos >= 0) {
-                return DOI.findInText(curString).map(DOI::asString).orElse(null);
-            }
+    private @Nullable String getDoi(@Nullable String currentDoi) {
+        if (currentDoi != null) {
+            return currentDoi;
         }
-        return doi;
+
+        return DOI.findInText(curString).map(DOI::asString).orElse(null);
     }
 
     private String getArXivId(String arXivId) {