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 KVSTORE_RESULT_SET_H 17 #define KVSTORE_RESULT_SET_H 18 19 #include "types.h" 20 21 namespace OHOS { 22 namespace DistributedKv { 23 class KvStoreResultSet { 24 public: ~KvStoreResultSet()25 KVSTORE_API virtual ~KvStoreResultSet() 26 {} 27 28 // Returns the count of rows in the result set. 29 KVSTORE_API virtual int GetCount() const = 0; 30 31 // Returns the current read position of the result set. 32 KVSTORE_API virtual int GetPosition() const = 0; 33 34 // Move the read position to the first row, return false if the result set is empty. 35 KVSTORE_API virtual bool MoveToFirst() = 0; 36 37 // Move the read position to the last row, return false if the result set is empty. 38 KVSTORE_API virtual bool MoveToLast() = 0; 39 40 // Move the read position to the next row, 41 // return false if the result set is empty or the read position is already past the last entry in the result set. 42 KVSTORE_API virtual bool MoveToNext() = 0; 43 44 // Move the read position to the previous row, 45 // return false if result set is empty or the read position is already before the first entry in the result set. 46 KVSTORE_API virtual bool MoveToPrevious() = 0; 47 48 // Move the read position by a relative amount from the current position. 49 KVSTORE_API virtual bool Move(int offset) = 0; 50 51 // Move the read position to an absolute position value. 52 KVSTORE_API virtual bool MoveToPosition(int position) = 0; 53 54 // Returns whether the read position is pointing to the first row. 55 KVSTORE_API virtual bool IsFirst() const = 0; 56 57 // Returns whether the read position is pointing to the last row. 58 KVSTORE_API virtual bool IsLast() const = 0; 59 60 // Returns whether the read position is before the first row. 61 KVSTORE_API virtual bool IsBeforeFirst() const = 0; 62 63 // Returns whether the read position is after the last row. 64 KVSTORE_API virtual bool IsAfterLast() const = 0; 65 66 // Get a key-value entry. 67 KVSTORE_API virtual Status GetEntry(Entry &entry) const = 0; 68 }; 69 } // namespace DistributedKv 70 } // namespace OHOS 71 #endif // KVSTORE_RESULT_SET_H 72