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 org.apache.hadoop.hbase.HBaseInterfaceAudience; 021import org.apache.yetus.audience.InterfaceAudience; 022import org.apache.yetus.audience.InterfaceStability; 023 024/** 025 * This is a special {@link ScannerContext} subclass that is designed to be used globally when 026 * limits should not be enforced during invocations of {@link InternalScanner#next(java.util.List)} 027 * or {@link RegionScanner#next(java.util.List)}. 028 * <p> 029 * Instances of {@link NoLimitScannerContext} are immutable after construction. Any attempt to 030 * change the limits or progress of a {@link NoLimitScannerContext} will fail silently. The net 031 * effect is that all limit checks will return false, thus indicating that a limit has not been 032 * reached. 033 */ 034@InterfaceAudience.LimitedPrivate(HBaseInterfaceAudience.COPROC) 035@InterfaceStability.Evolving 036public class NoLimitScannerContext extends ScannerContext { 037 038 public NoLimitScannerContext() { 039 super(false, null, false); 040 } 041 042 /** 043 * Use this instance whenever limits do not need to be enforced. 044 */ 045 private static final ScannerContext NO_LIMIT = new NoLimitScannerContext(); 046 047 /** 048 * Returns the static, immutable instance of {@link NoLimitScannerContext} to be used whenever 049 * limits should not be enforced 050 */ 051 @edu.umd.cs.findbugs.annotations.SuppressWarnings(value = "MS_EXPOSE_REP", 052 justification = "singleton pattern") 053 public static final ScannerContext getInstance() { 054 return NO_LIMIT; 055 } 056 057 @Override 058 void setKeepProgress(boolean keepProgress) { 059 // Do nothing. NoLimitScannerContext instances are immutable post-construction 060 } 061 062 @Override 063 void setBatchProgress(int batchProgress) { 064 // Do nothing. NoLimitScannerContext instances are immutable post-construction 065 } 066 067 @Override 068 void setSizeProgress(long sizeProgress, long heapSizeProgress) { 069 // Do nothing. NoLimitScannerContext instances are immutable post-construction 070 } 071 072 @Override 073 void setProgress(int batchProgress, long sizeProgress, long heapSizeProgress) { 074 // Do nothing. NoLimitScannerContext instances are immutable post-construction 075 } 076 077 @Override 078 void clearProgress() { 079 // Do nothing. NoLimitScannerContext instances are immutable post-construction 080 } 081 082 @Override 083 void setSizeLimitScope(LimitScope scope) { 084 // Do nothing. NoLimitScannerContext instances are immutable post-construction 085 } 086 087 @Override 088 void setTimeLimitScope(LimitScope scope) { 089 // Do nothing. NoLimitScannerContext instances are immutable post-construction 090 } 091 092 @Override 093 NextState setScannerState(NextState state) { 094 // Do nothing. NoLimitScannerContext instances are immutable post-construction 095 return state; 096 } 097 098 @Override 099 boolean checkBatchLimit(LimitScope checkerScope) { 100 // No limits can be specified, thus return false to indicate no limit has been reached. 101 return false; 102 } 103 104 @Override 105 boolean checkSizeLimit(LimitScope checkerScope) { 106 // No limits can be specified, thus return false to indicate no limit has been reached. 107 return false; 108 } 109 110 @Override 111 boolean checkTimeLimit(LimitScope checkerScope) { 112 // No limits can be specified, thus return false to indicate no limit has been reached. 113 return false; 114 } 115 116 @Override 117 boolean checkAnyLimitReached(LimitScope checkerScope) { 118 return false; 119 } 120}