001/* 002 * Licensed to the Apache Software Foundation (ASF) under one 003 * or more contributor license agreements. See the NOTICE file 004 * distributed with this work for additional information 005 * regarding copyright ownership. The ASF licenses this file 006 * to you under the Apache License, Version 2.0 (the 007 * "License"); you may not use this file except in compliance 008 * with the License. You may obtain a copy of the License at 009 * 010 * http://www.apache.org/licenses/LICENSE-2.0 011 * 012 * Unless required by applicable law or agreed to in writing, software 013 * distributed under the License is distributed on an "AS IS" BASIS, 014 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 015 * See the License for the specific language governing permissions and 016 * limitations under the License. 017 */ 018package org.apache.hadoop.hbase.regionserver; 019 020import java.io.IOException; 021import java.util.ArrayList; 022import java.util.List; 023import org.apache.hadoop.hbase.CellComparator; 024import org.apache.hadoop.hbase.ExtendedCell; 025import org.apache.yetus.audience.InterfaceAudience; 026 027/** 028 * The MemStoreMergerSegmentsIterator extends MemStoreSegmentsIterator and performs the scan for 029 * simple merge operation meaning it is NOT based on SQM 030 */ 031@InterfaceAudience.Private 032public class MemStoreMergerSegmentsIterator extends MemStoreSegmentsIterator { 033 034 // heap of scanners, lazily initialized 035 private KeyValueHeap heap = null; 036 // remember the initial version of the scanners list 037 List<KeyValueScanner> scanners = new ArrayList<KeyValueScanner>(); 038 039 private boolean closed = false; 040 041 // C-tor 042 public MemStoreMergerSegmentsIterator(List<ImmutableSegment> segments, CellComparator comparator, 043 int compactionKVMax) throws IOException { 044 super(compactionKVMax); 045 // create the list of scanners to traverse over all the data 046 // no dirty reads here as these are immutable segments 047 AbstractMemStore.addToScanners(segments, Long.MAX_VALUE, scanners); 048 heap = new KeyValueHeap(scanners, comparator); 049 } 050 051 @Override 052 public boolean hasNext() { 053 if (closed) { 054 return false; 055 } 056 if (this.heap != null) { 057 return (this.heap.peek() != null); 058 } 059 // Doing this way in case some test cases tries to peek directly 060 return false; 061 } 062 063 @Override 064 public ExtendedCell next() { 065 try { // try to get next 066 if (!closed && heap != null) { 067 return heap.next(); 068 } 069 } catch (IOException ie) { 070 throw new IllegalStateException(ie); 071 } 072 return null; 073 } 074 075 @Override 076 public void close() { 077 if (closed) { 078 return; 079 } 080 // Ensuring that all the segment scanners are closed 081 if (heap != null) { 082 heap.close(); 083 // It is safe to do close as no new calls will be made to this scanner. 084 heap = null; 085 } else { 086 for (KeyValueScanner scanner : scanners) { 087 scanner.close(); 088 } 089 } 090 closed = true; 091 } 092 093 @Override 094 public void remove() { 095 throw new UnsupportedOperationException(); 096 } 097}