added comments

src/main/java/com/skt/ehs/mbs/fpbuilder/BLEFPBuilder.java

@@ -3,7 +3,6 @@ package com.skt.ehs.mbs.fpbuilder;
 import com.skt.ehs.mbs.db.maria.DBManager;
 import com.skt.ehs.mbs.db.maria.MariaConnectionManager;
 import com.skt.ehs.mbs.db.maria.dao.FPBLEBuildDAO;
-import com.sun.java.swing.plaf.windows.WindowsTreeUI;
 import org.apache.ibatis.session.SqlSession;
 
 import java.util.*;
@@ -115,7 +114,6 @@ public class BLEFPBuilder {
         double scale_pixel = readMapScale();
         System.out.println("scale_pixel : "+scale_pixel);
         mFloor.setMap_scale_pixel(scale_pixel);
-        // Todo access DB & calculate factor & build fp.
 
 /*********************** Loop of loop here ... *************************************/
         // 수집방향 맵 준비
@@ -152,16 +150,19 @@ public class BLEFPBuilder {
                 new _ble_indicator("cccc", 6666),
                 new _ble_indicator("bbbb", 7777));
 
-
+        // transform list to map
         Map<String,List<Integer>> transform  =   sample2.stream().collect(Collectors.groupingBy(_ble_indicator::get_ap_id,
                 Collectors.mapping(_ble_indicator::get_rssi,Collectors.toList())));
 
         // prepare for insert value for storing
         List<_fp_elem> fp_per_cell = new ArrayList<>();
 
+        // map traverse using set view
         Set<Map.Entry<String, List<Integer>>> entries = transform.entrySet();
         for(Map.Entry<String,List<Integer>> entry : entries ) {
             List<Integer> rssi_list = entry.getValue();
+
+            // calculate statistics
             final int count = rssi_list.size();
             final double rssi_min = rssi_list.stream().mapToDouble(Integer::doubleValue).summaryStatistics().getMin();
             final double rssi_max = rssi_list.stream().mapToDouble(Integer::doubleValue).summaryStatistics().getMax();
@@ -178,7 +179,8 @@ public class BLEFPBuilder {
             System.out.println(print_elem);
         }
         // calculate mag_angle -  해당 cell의 각 수집방향에 대하여 수집된 지자기방향의 평균값으로 대표
-        // then insert into fp_ble_data table
+
+        // insert rows to db.