Refine documentation (#8551)

* Refine documentation

* Update SearchBasedParserFetcher.java


Co-authored-by: Siedlerchr <siederkiller@gmail.com>
Co-authored-by: Tobias Diez <tobiasdiez@gmx.de>

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

@@ -8,6 +8,7 @@
 import java.util.List;
 
 import org.jabref.logic.cleanup.Formatter;
+import org.jabref.logic.importer.fetcher.MedlineFetcher;
 import org.jabref.model.entry.BibEntry;
 
 import org.apache.lucene.queryparser.flexible.core.nodes.QueryNode;
@@ -20,14 +21,24 @@
  *     <li>Post-process fetched entries</li>
  * </ol>
  * <p>
- *     This interface is used for web resources which do NOT provide BibTeX data {@link BibEntry}.
+ *    Normally, a fetcher invokes an API and then parses the response (to get BibEntries).
+ *    This kind of workflow is supported by the parser-based fetcher.
+ *    Sometimes you need to have more flexibility, i.e. call multiple endpoints and merge the results etc.
+ *    In theses cases, one has to use the non-parser-based fetcher interfaces.
+ * <p>
+ * <p>
+ *     This interface is used for web resources which do NOT provide BibTeX data {@link BibEntry} directly.
  *     JabRef's infrastructure to convert arbitrary input data to BibTeX is {@link Parser}.
  * </p>
  * <p>
  *     This interface inherits {@link SearchBasedFetcher}, because the methods <code>performSearch</code> have to be provided by both.
  *     As non-BibTeX web fetcher one could do "magic" stuff without this helper interface and directly use {@link WebFetcher}, but this is more work.
  * </p>
  * <p>
+ *     The idea is the one can reuse an importer in the place of a Parser.
+ *     See {@link MedlineFetcher#getParser()} for an example.
+ * </p>
+ * <p>
  *     Note that this interface "should" be an abstract class.
  *     However, Java does not support multi inheritance with classes (but with interfaces).
  *     We need multi inheritance, because a fetcher might implement multiple query types (such as id fetching {@link IdBasedFetcher}), complete entry {@link EntryBasedFetcher}, and search-based fetcher (this class).