working on tak use list

Signed-off-by: Stephan Richter <s.richter@srsoftware.de>

tags/src/main/java/de/srsoftware/umbrella/tags/SqliteDb.java

@@ -4,6 +4,7 @@ package de.srsoftware.umbrella.tags;
 import static de.srsoftware.tools.jdbc.Condition.equal;
 import static de.srsoftware.tools.jdbc.Condition.isNull;
 import static de.srsoftware.tools.jdbc.Query.*;
+import static de.srsoftware.tools.jdbc.Query.SelectQuery.ALL;
 import static de.srsoftware.umbrella.core.Constants.*;
 import static de.srsoftware.umbrella.core.Constants.ERROR_FAILED_CREATE_TABLE;
 import static de.srsoftware.umbrella.core.Constants.USER_ID;
@@ -16,9 +17,7 @@ import de.srsoftware.tools.jdbc.Query;
 import de.srsoftware.umbrella.core.exceptions.UmbrellaException;
 import java.sql.Connection;
 import java.sql.SQLException;
-import java.util.Collection;
-import java.util.HashSet;
-import java.util.Set;
+import java.util.*;
 
 public class SqliteDb implements TagDB{
 	private static final int INITIAL_DB_VERSION = 1;
@@ -110,6 +109,23 @@ CREATE TABLE IF NOT EXISTS "{0}" (
 		}
 	}
 
+	@Override
+	public Map<String, List<Long>> getUses(String tag, long userId) {
+		try {
+			var rs = select(ALL).from(TABLE_TAGS).where(TAG,equal(tag)).where(USER_ID,equal(userId)).exec(db);
+			var result = new HashMap<String,List<Long>>();
+			while (rs.next()){
+				var module = rs.getString(MODULE);
+				var entityId = rs.getLong(ID);
+				result.computeIfAbsent(module, k -> new ArrayList<>()).add(entityId);
+			}
+			rs.close();
+			return result;
+		} catch (SQLException e){
+			throw new UmbrellaException("Failed to load uses of tag \"{0}\"!",tag);
+		}
+	}
+
 	private void init(){
 		var version = createTables();
 		LOG.log(INFO,"Updated task db to version {0}",version);

tags/src/main/java/de/srsoftware/umbrella/tags/TagDB.java

@@ -2,6 +2,8 @@
 package de.srsoftware.umbrella.tags;
 
 import java.util.Collection;
+import java.util.List;
+import java.util.Map;
 import java.util.Set;
 
 public interface TagDB {
@@ -9,6 +11,8 @@ public interface TagDB {
 
 	void deleteEntity(String module, long entityId);
 
+	Map<String, List<Long>> getUses(String tag, long id);
+
 	Set<String> list(long id, String module, long entityId);
 
 	void save(Collection<Long> userIds, String module, long entityId, Collection<String> tags);

tags/src/main/java/de/srsoftware/umbrella/tags/TagModule.java

@@ -68,6 +68,7 @@ public class TagModule extends BaseHandler implements TagService {
 			var module = path.pop();
 			if (module == null) throw unprocessable("Module missing in path.");
 			var head = path.pop();
+			if (USES.equals(module)) return getTagUses(ex,head,user.get());
 			long entityId = Long.parseLong(head);
 			return sendContent(ex, getTags(module,entityId,user.get()));
 		} catch (NumberFormatException e){
@@ -77,6 +78,10 @@ public class TagModule extends BaseHandler implements TagService {
 		}
 	}
 
+	private boolean getTagUses(HttpExchange ex, String tag, UmbrellaUser user) throws IOException {
+		return sendContent(ex,tagDb.getUses(tag,user.id()));
+	}
+
 	@Override
 	public boolean doOptions(Path path, HttpExchange ex) throws IOException {
 		addCors(ex);