1 /** 2 * 3 * Licensed to the Apache Software Foundation (ASF) under one 4 * or more contributor license agreements. See the NOTICE file 5 * distributed with this work for additional information 6 * regarding copyright ownership. The ASF licenses this file 7 * to you under the Apache License, Version 2.0 (the 8 * "License"); you may not use this file except in compliance 9 * with the License. You may obtain a copy of the License at 10 * 11 * http://www.apache.org/licenses/LICENSE-2.0 12 * 13 * Unless required by applicable law or agreed to in writing, software 14 * distributed under the License is distributed on an "AS IS" BASIS, 15 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 16 * See the License for the specific language governing permissions and 17 * limitations under the License. 18 */ 19 package org.apache.hadoop.hbase.regionserver; 20 21 import java.io.Closeable; 22 import java.io.IOException; 23 import java.util.List; 24 25 import org.apache.hadoop.hbase.Cell; 26 import org.apache.hadoop.hbase.HBaseInterfaceAudience; 27 import org.apache.hadoop.hbase.classification.InterfaceAudience; 28 import org.apache.hadoop.hbase.classification.InterfaceStability; 29 30 /** 31 * Internal scanners differ from client-side scanners in that they operate on 32 * HStoreKeys and byte[] instead of RowResults. This is because they are 33 * actually close to how the data is physically stored, and therefore it is more 34 * convenient to interact with them that way. It is also much easier to merge 35 * the results across SortedMaps than RowResults. 36 * 37 * <p>Additionally, we need to be able to determine if the scanner is doing 38 * wildcard column matches (when only a column family is specified or if a 39 * column regex is specified) or if multiple members of the same column family 40 * were specified. If so, we need to ignore the timestamp to ensure that we get 41 * all the family members, as they may have been last updated at different 42 * times. 43 */ 44 @InterfaceAudience.LimitedPrivate(HBaseInterfaceAudience.COPROC) 45 @InterfaceStability.Evolving 46 public interface InternalScanner extends Closeable { 47 /** 48 * Grab the next row's worth of values. 49 * @param results return output array 50 * @return true if more rows exist after this one, false if scanner is done 51 * @throws IOException e 52 */ 53 boolean next(List<Cell> results) throws IOException; 54 55 /** 56 * Grab the next row's worth of values. 57 * @param result return output array 58 * @param scannerContext 59 * @return true if more rows exist after this one, false if scanner is done 60 * @throws IOException e 61 */ 62 boolean next(List<Cell> result, ScannerContext scannerContext) throws IOException; 63 64 /** 65 * Closes the scanner and releases any resources it has allocated 66 * @throws IOException 67 */ 68 void close() throws IOException; 69 }