--- a/src/main/java/de/mpiwg/gazetteer/utils/DataProvider.java	Mon Dec 07 17:06:57 2015 +0100
+++ b/src/main/java/de/mpiwg/gazetteer/utils/DataProvider.java	Thu Dec 17 13:44:08 2015 +0100
@@ -1,5 +1,6 @@
 package de.mpiwg.gazetteer.utils;
 
+import java.sql.SQLException;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.Date;
@@ -12,7 +13,10 @@
 import de.mpiwg.gazetteer.bo.LGBranch;
 import de.mpiwg.gazetteer.bo.LGFile;
 import de.mpiwg.gazetteer.bo.LGFullTextSearchFile;
+import de.mpiwg.gazetteer.bo.LGTopic;
+import de.mpiwg.gazetteer.bo.LGTopicSectionRelation;
 import de.mpiwg.gazetteer.db.DBContents;
+import de.mpiwg.gazetteer.db.DBSection;
 import de.mpiwg.gazetteer.utils.exceptions.NoAuthorizedException;
 import de.mpiwg.gazetteer.utils.exceptions.VersioningException;
 
@@ -34,6 +38,11 @@
 	public DataProvider(){
 		logger.info("##### Starting DataProvider #####");
 	}
+	
+	
+
+	/* --- branch --- */
+	
 	public LGFile getFile(Long fileId){
 		return getFileMap().getValuesByOwnKey(fileId);
 	}
@@ -259,6 +268,11 @@
 		
 	}
 
+	/* --- end branch --- */
+	
+	
+	
+	/* --- full text search --- */
 	
 	public List<LGFullTextSearchFile> getSearchFileList4User(Long userId) {
 	
@@ -303,7 +317,179 @@
 		return file;
 	}
 
+	/* --- end full text search --- */
+
+	/* --- topic --- */
 	
+	public List<LGTopic> getTopics(Long userId){
+		List<LGTopic> list = new ArrayList<LGTopic>();
+		for(LGTopic topic : getTopicMap().values()){
+			if(topic.hasContributor(userId)){
+				list.add(topic);
+			}
+		}
+		return list;
+	}
+	
+	public LGTopic getTopic(Long topicId){
+		return getTopicMap().getValuesByOwnKey(topicId);
+	}
+	
+	
+	public void deleteTopic(LGTopic topic){
+			
+		int modifiedRelation = DBService.deleteTopicFromDB(topic.getId());
+		getTopicMap().remove(topic.getKey());
+		
+		logger.info("removing " + modifiedRelation + " records in topicSectionRelation of topic " + topic.toString());
+		
+		this.setTopicSectionRelationMap(null);	// clear topicSectionRelationMap cache
+		
+
+	}
+
+	public void createTopic(String nameEn, String nameCh,String namePinyin, String description, Long userId) {
+		Date date = new Date();
+		
+		LGTopic topic = new LGTopic();
+		topic.setNameEn(nameEn);
+		topic.setNameCh(nameCh);
+		topic.setNamePinyin(namePinyin);
+		topic.setDescription(description);
+		topic.setUserId(userId);
+		topic.setContributors("[" + userId.toString() + "]");
+		
+		//Saving into DB
+		//##################################
+		// For Topic table
+		Session session = HibernateUtil.getSessionFactory().getCurrentSession();
+		session.getTransaction().begin();
+		
+		DBService.saveDBEntry0(session, topic, date);
+			
+		session.getTransaction().commit();
+		//##################################
+		
+	}
+
+	public void updateTopic(LGTopic topic) throws Exception {
+		if(!topic.isPersistent()){
+			throw new Exception("Trying to update a topic that it is not persistent!");
+		}
+		
+		Date date = new Date();
+		DBService.saveDBEntry(topic, date);
+		this.getTopicMap().put(topic.getKey(), topic);
+		
+	}
+	
+	
+	
+	public List<DBSection> getAllSectionsInTopic(Long topicId) throws SQLException{
+		
+		List<LGTopicSectionRelation> topicSectionRelationList = getTopicSectionRelationMap().getValuesByAKey(topicId);
+
+		// get sections from topicSecionRelation list
+		List<DBSection> list = new ArrayList<DBSection>();
+		for (LGTopicSectionRelation aRelation : topicSectionRelationList) {
+			logger.debug(aRelation.getInfo() );
+			
+			DBSection section = DBService.getSectionWithContent(aRelation.getSectionId());
+			list.add(section);
+			
+		}
+		
+		
+		Collections.sort(list);
+		Collections.reverse(list);
+		return list;
+	}
+
+
+
+
+	public void deleteTopicSectionRelation(Long topicId, String bookId) throws Exception{
+		// delete record with topicId, bookId in topicSectionRelation
+		// this means the sectionId = 0, there is no corresponding section in the book for this topic
+		
+		// TODO
+		
+	}
+
+	public void deleteTopicSectionRelation(Long topicId, Long sectionId) throws Exception{
+		if (sectionId == 0) {
+			throw new Exception("sectionId cannot be 0");
+		}
+		
+		DuplexKey<Long, Long> key = new DuplexKey<Long, Long>(topicId, sectionId);
+		LGTopicSectionRelation topicSectionRelation = this.getTopicSectionRelationMap().get(key);
+
+		LGTopic topic = getTopic(topicId);
+		
+		if(topic == null){
+			throw new Exception("There is no topic of " + topicSectionRelation);
+		}
+		
+		//deleting topicSectionRelation from DB and cache
+		int modifiedRelation = DBService.deleteTopicSectionRelationFromDB(topicSectionRelation.getId());
+		getTopicSectionRelationMap().remove(topicSectionRelation.getKey());
+		
+		logger.info(modifiedRelation + " items deleted by removing topicSectionRelation " + topicSectionRelation.toString());
+
+		
+	}
+
+	public String updateTopicSectionRelation(Long sectionId, Long topicId) throws Exception {
+		DuplexKey<Long, Long> key = new DuplexKey<Long, Long>(topicId, sectionId);
+		LGTopicSectionRelation topicSectionRelation = this.getTopicSectionRelationMap().get(key);
+
+		if (topicSectionRelation != null) {
+			// the relation already existed
+			// would this possibly need any modification to the existing record in the topicSectionRelation table?
+			
+			return "updated";
+			
+		} else {
+			createTopicSectionRelation(sectionId, topicId);
+
+			return "added";
+		}
+		
+	
+		
+	}
+	
+	
+	public void createTopicSectionRelation(Long sectionId, Long topicId) throws Exception {
+		
+		Date date = new Date();
+		
+		LGTopicSectionRelation topicSectionRelation = new LGTopicSectionRelation();
+		topicSectionRelation.setTopicId(topicId);
+		topicSectionRelation.setSectionId(sectionId);
+		
+		DBService.getInstance();
+		DBSection section = DBService.getSectionWithContent(sectionId);
+		topicSectionRelation.setBookId(section.getBookId());
+		
+		//Saving into DB
+		//##################################
+		// For Topic table
+		Session session = HibernateUtil.getSessionFactory().getCurrentSession();
+		session.getTransaction().begin();
+		
+		DBService.saveDBEntry0(session, topicSectionRelation, date);
+			
+		session.getTransaction().commit();
+		//##################################
+		
+		// update cache
+		this.loadTopicSectionRelations();
+	
+	}
 
 	
+	
+	/* --- end topic --- */
+	
 }