Resolve "Relevance Ranking in Metadata"

Required MRs to be merged before

• codeabilitysharingpluginapi!2 (merged)
• !217 (merged)
• codeabilitysharingpluginapi!3 (merged)

Related to #439 (closed)

src/main/java/at/ac/uibk/gitsearch/repository/search/MetaDataRepository.java

@@ -7,6 +7,9 @@ import at.ac.uibk.gitsearch.repository.jpa.StatisticsRepository;
 import at.ac.uibk.gitsearch.service.dto.AutoCompleteEntry;
 import at.ac.uibk.gitsearch.service.dto.StatisticsDTO;
 import co.elastic.clients.elasticsearch.ElasticsearchClient;
+import co.elastic.clients.elasticsearch._types.FieldSort;
+import co.elastic.clients.elasticsearch._types.SortOptions;
+import co.elastic.clients.elasticsearch._types.SortOrder;
 import co.elastic.clients.elasticsearch._types.query_dsl.BoolQuery;
 import co.elastic.clients.elasticsearch._types.query_dsl.ExistsQuery;
 import co.elastic.clients.elasticsearch._types.query_dsl.MatchPhrasePrefixQuery;
@@ -565,7 +568,13 @@ public class MetaDataRepository {
             final BoolQuery query = queryBuilder.build();
             // LOGGER.info("ElasticSearch Query using Java Client API:\n{}", query)
             co.elastic.clients.elasticsearch.core.SearchResponse<SearchResultDTO> searchResponse = elasticsearchAPIClient.search(
-                search -> search.index(SearchRepositoryConstants.INDEX_METADATA).query(q -> q.bool(query)).from(from).size(pageSize),
+                search ->
+                    search
+                        .index(SearchRepositoryConstants.INDEX_METADATA)
+                        .query(q -> q.bool(query))
+                        .sort(getDefaultSortStrategy())
+                        .from(from)
+                        .size(pageSize),
                 SearchResultDTO.class
             );
 
@@ -583,6 +592,18 @@ public class MetaDataRepository {
         }
     }
 
+    private List<SortOptions> getDefaultSortStrategy() {
+        return List.of(
+            getSortOptionForFieldAndOrder(SearchRepositoryConstants.SEARCHSTATISTICS_BADGEREWARDED, SortOrder.Desc),
+            getSortOptionForFieldAndOrder(SearchRepositoryConstants.SEARCHSTATISTICS_DOWNLOADS, SortOrder.Desc),
+            getSortOptionForFieldAndOrder(SearchRepositoryConstants.SEARCHSTATISTICS_VIEWS, SortOrder.Desc)
+        );
+    }
+
+    private SortOptions getSortOptionForFieldAndOrder(String field, SortOrder order) {
+        return SortOptions.of(sb -> sb.field(FieldSort.of(fb -> fb.field(field).order(order))));
+    }
+
     /**
      * creates the query (builder) for the searchInput and the user authorization
      *