1 /** 2 * Licensed to the Apache Software Foundation (ASF) under one 3 * or more contributor license agreements. See the NOTICE file 4 * distributed with this work for additional information 5 * regarding copyright ownership. The ASF licenses this file 6 * to you under the Apache License, Version 2.0 (the 7 * "License"); you may not use this file except in compliance 8 * with the License. You may obtain a copy of the License at 9 * 10 * http://www.apache.org/licenses/LICENSE-2.0 11 * 12 * Unless required by applicable law or agreed to in writing, software 13 * distributed under the License is distributed on an "AS IS" BASIS, 14 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 15 * See the License for the specific language governing permissions and 16 * limitations under the License. 17 */ 18 19 package org.apache.hadoop.hbase.codec.prefixtree.scanner; 20 21 import org.apache.hadoop.hbase.classification.InterfaceAudience; 22 23 /** 24 * An indicator of the state of the scanner after an operation such as nextCell() or 25 * positionAt(..). For example: 26 * <ul> 27 * <li>In a DataBlockScanner, the AFTER_LAST position indicates to the parent StoreFileScanner that 28 * it should load the next block.</li> 29 * <li>In a StoreFileScanner, the AFTER_LAST position indicates that the file has been exhausted. 30 * </li> 31 * <li>In a RegionScanner, the AFTER_LAST position indicates that the scanner should move to the 32 * next region.</li> 33 * </ul> 34 */ 35 @InterfaceAudience.Private 36 public enum CellScannerPosition { 37 38 /** 39 * getCurrentCell() will NOT return a valid cell. Calling nextCell() will advance to the first 40 * cell. 41 */ 42 BEFORE_FIRST, 43 44 /** 45 * getCurrentCell() will return a valid cell, but it is not the cell requested by positionAt(..), 46 * rather it is the nearest cell before the requested cell. 47 */ 48 BEFORE, 49 50 /** 51 * getCurrentCell() will return a valid cell, and it is exactly the cell that was requested by 52 * positionAt(..). 53 */ 54 AT, 55 56 /** 57 * getCurrentCell() will return a valid cell, but it is not the cell requested by positionAt(..), 58 * rather it is the nearest cell after the requested cell. 59 */ 60 AFTER, 61 62 /** 63 * getCurrentCell() will NOT return a valid cell. Calling nextCell() will have no effect. 64 */ 65 AFTER_LAST 66 67 }