二阶 group by 实现

/**
      * 默认返回select * 的结果 输入就是生成的数据 输入的数据不同于cloudwave的就是没有排序
      * 
      * @param type
      *            0没有括号 1max 2min 3sum 4avg 5count
      */
     public static Object[][] groupby(OneRow[] rows,
                                      int[] groupbyIndex,
                                      int type) {
         display(rows);
         Object[][] resultMatrix = new Object[rows.length][OneRow.colCount];
         if (type == 0) {
             // 鉴于有很多groupby的列，就从前到后 两两 两两 的分析
             List<KeyAndRows>[] map = new ArrayList[groupbyIndex.length];
             for (int i = 0; i < map.length; i++) {
                 map[i] = new ArrayList<KeyAndRows>();
             }


             int groupbyColumn = groupbyIndex[0];
             for (int i = 0; i < rows.length; i++) {
                 Object key = rows[i].column[groupbyColumn];
                 if (contains(map[0],
                              key)) {
                     int index = indexOf(map[0],
                                         key);
                     map[0].get(index).list.add(i);
                     map[0].add(index,
                                map[0].get(index));
                     map[0].remove(index+1);
                 } else {
                     List<Integer> list = new ArrayList();
                     KeyAndRows kr = new KeyAndRows(key,
                                                    list);
                     kr.list.add(i);
                     map[0].add(kr);
                 }
             }


             System.out.println();
             KeyAndRows[] krs = map[0].toArray(new KeyAndRows[0]);
             display2(krs);


             for (int i = 0; i < map[0].size(); i++) {
                 KeyAndRows kr = map[0].get(i);
                 groupbyColumn = groupbyIndex[1];
                 for (int row : kr.list) {
                     Object key = rows[row].column[groupbyColumn];
                     if (contains(map[1],
                                  key)) {
                         int index = indexOf(map[1],
                                             key);
                         map[1].get(index).list.add(row);
                         map[1].add(index,
                                    map[1].get(index));
                         map[1].remove(index+1);
                     } else {
                         List<Integer> list = new ArrayList();
                         KeyAndRows kr2 = new KeyAndRows(key,
                                                         list);
                         kr2.list.add(row);
                         map[1].add(kr2);
                     }
                 }
                 for (KeyAndRows krTemp : map[1]) {
                     krTemp.key = null;
                 }
             }


             System.out.println();
             krs = map[1].toArray(new KeyAndRows[0]);
             display2(krs);
         }
         return null;
     }

static class KeyAndRows {
         public Object key;
         public List<Integer> list;


         public KeyAndRows(Object key,
                           List<Integer> list) {
             this.key = key;
             this.list = list;
         }
     }


     public static void display(OneRow[] rows) {
         for (int i = 0; i < rows.length; i++) {
             for (int j = 0; j < 13; j++) {
                 System.out.print(rows[i].column[j]
                                  + " ");
             }
             System.out.println();
         }
     }


     public static boolean contains(List<KeyAndRows> map,
                                    Object key) {
         int count = map.size();
         for (int i = 0; i < count; i++) {
             if (map.get(i).key != null
                 && map.get(i).key.equals(key)) {
                 return true;
             }
         }
         return false;
     }


     public static int indexOf(List<KeyAndRows> map,
                               Object key) {
         int count = map.size();
         for (int i = 0; i < count; i++) {
             if (map.get(i).key != null
                 && map.get(i).key.equals(key)) {
                 return i;
             }
         }
         return -1;
     }
    private static void display2(KeyAndRows[] krs) {
         for (int i = 0; i < krs.length; i++) {
             System.out.print(krs[i].key);
             for (int j = 0; j < krs[i].list.size(); j++) {
                 System.out.print(" "
                                  + krs[i].list.get(j));
             }
             System.out.println();
         }
     }