1 /* 2 * Copyright (c) 2021 Huawei Device Co., Ltd. 3 * Licensed under the Apache License, Version 2.0 (the "License"); 4 * you may not use this file except in compliance with the License. 5 * You may obtain a copy of the License at 6 * 7 * http://www.apache.org/licenses/LICENSE-2.0 8 * 9 * Unless required by applicable law or agreed to in writing, software 10 * distributed under the License is distributed on an "AS IS" BASIS, 11 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12 * See the License for the specific language governing permissions and 13 * limitations under the License. 14 */ 15 16 #ifndef KV_STORE_RESULT_SET_H 17 #define KV_STORE_RESULT_SET_H 18 19 #include "store_types.h" 20 21 namespace DistributedDB { 22 class KvStoreResultSet { 23 public: ~KvStoreResultSet()24 DB_API virtual ~KvStoreResultSet() {}; 25 26 // Returns the count of rows in the result set. 27 DB_API virtual int GetCount() const = 0; 28 29 // Returns the current read position of the result set. 30 DB_API virtual int GetPosition() const = 0; 31 32 // Move the read position to the first row, return false if the result set is empty. 33 DB_API virtual bool MoveToFirst() = 0; 34 35 // Move the read position to the last row, return false if the result set is empty. 36 DB_API virtual bool MoveToLast() = 0; 37 38 // Move the read position to the next row, return false if the result set is empty 39 // or the read position is already past the last entry in the result set. 40 DB_API virtual bool MoveToNext() = 0; 41 42 // Move the read position to the previous row, return false if the result set is empty 43 // or the read position is already before the first entry in the result set. 44 DB_API virtual bool MoveToPrevious() = 0; 45 46 // Move the read position by a relative amount from the current position. 47 DB_API virtual bool Move(int offset) = 0; 48 49 // Move the read position to an absolute position value. 50 DB_API virtual bool MoveToPosition(int position) = 0; 51 52 // Returns whether the read position is pointing to the first row. 53 DB_API virtual bool IsFirst() const = 0; 54 55 // Returns whether the read position is pointing to the last row. 56 DB_API virtual bool IsLast() const = 0; 57 58 // Returns whether the read position is before the first row. 59 DB_API virtual bool IsBeforeFirst() const = 0; 60 61 // Returns whether the read position is after the last row 62 DB_API virtual bool IsAfterLast() const = 0; 63 64 // Get a key-value entry. 65 DB_API virtual DBStatus GetEntry(Entry &entry) const = 0; 66 }; 67 } // namespace DistributedDB 68 69 #endif // KV_STORE_RESULT_SET_H