Resolve "Die Statistiken sollten auch in ElasticSearch hinterlegt werden."

Related to #384 (closed)

src/main/java/at/ac/uibk/gitsearch/service/vocabulary/VocabularyService.java

 package at.ac.uibk.gitsearch.service.vocabulary;
 
-import at.ac.uibk.gitsearch.domain.vocabulary.DifficultyItem;
-import at.ac.uibk.gitsearch.domain.vocabulary.KeywordItem;
-import at.ac.uibk.gitsearch.domain.vocabulary.ProgrammingLanguageItem;
-import at.ac.uibk.gitsearch.domain.vocabulary.VocabularyItem;
-import at.ac.uibk.gitsearch.repository.vocabulary.VocabularyRepository;
 import java.net.URL;
 import java.util.Map;
+
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.stereotype.Service;
 import org.springframework.transaction.annotation.Transactional;
 
+import at.ac.uibk.gitsearch.domain.vocabulary.DifficultyItem;
+import at.ac.uibk.gitsearch.domain.vocabulary.KeywordItem;
+import at.ac.uibk.gitsearch.domain.vocabulary.ProgrammingLanguageItem;
+import at.ac.uibk.gitsearch.domain.vocabulary.VocabularyItem;
+import at.ac.uibk.gitsearch.repository.vocabulary.VocabularyRepository;
+
 @Service
 @Transactional
 public class VocabularyService {
@@ -53,17 +55,17 @@ public class VocabularyService {
         return (DifficultyItem[]) vocabularyRepository.getVocabularyItemsFor("difficulties", DifficultyItem.class);
     }
 
-    public String mapFromAPIToMetaDataField(String apiName) {
-        switch (apiName) {
-            case "keywords":
-                return "keyword";
-            case "difficulties":
-                return "difficulty";
-            case "programming-languages":
-                return "programmingLanguage";
+	public String mapFromMetaDataFieldToAPIield(String metaDataField) {
+		switch (metaDataField) {
+			case "keyword" :
+				return "keywords";
+			case "difficulty" :
+				return "difficulties";
+			case "programmingLanguage" :
+				return "programming-languages";
             default:
-                log.warn("Cannot map {}", apiName);
-                return "unknown";
+				log.warn("Cannot map {}", metaDataField);
+				return null;
         }
     }
 }