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.client.example; 019 020import static org.apache.hadoop.hbase.util.FutureUtils.addListener; 021 022import java.util.concurrent.CompletableFuture; 023import java.util.concurrent.CountDownLatch; 024import java.util.concurrent.ExecutorService; 025import java.util.concurrent.Executors; 026import java.util.concurrent.atomic.AtomicReference; 027import java.util.stream.IntStream; 028import org.apache.commons.io.IOUtils; 029import org.apache.hadoop.conf.Configured; 030import org.apache.hadoop.hbase.TableName; 031import org.apache.hadoop.hbase.client.AsyncConnection; 032import org.apache.hadoop.hbase.client.AsyncTable; 033import org.apache.hadoop.hbase.client.ConnectionFactory; 034import org.apache.hadoop.hbase.client.Get; 035import org.apache.hadoop.hbase.client.Put; 036import org.apache.hadoop.hbase.util.Bytes; 037import org.apache.hadoop.hbase.util.Threads; 038import org.apache.hadoop.util.Tool; 039import org.apache.hadoop.util.ToolRunner; 040import org.apache.hbase.thirdparty.com.google.common.util.concurrent.ThreadFactoryBuilder; 041import org.apache.yetus.audience.InterfaceAudience; 042import org.slf4j.Logger; 043import org.slf4j.LoggerFactory; 044 045/** 046 * A simple example shows how to use asynchronous client. 047 */ 048@InterfaceAudience.Private 049public class AsyncClientExample extends Configured implements Tool { 050 051 private static final Logger LOG = LoggerFactory.getLogger(AsyncClientExample.class); 052 053 /** 054 * The size for thread pool. 055 */ 056 private static final int THREAD_POOL_SIZE = 16; 057 058 /** 059 * The default number of operations. 060 */ 061 private static final int DEFAULT_NUM_OPS = 100; 062 063 /** 064 * The name of the column family. d for default. 065 */ 066 private static final byte[] FAMILY = Bytes.toBytes("d"); 067 068 /** 069 * For the example we're just using one qualifier. 070 */ 071 private static final byte[] QUAL = Bytes.toBytes("test"); 072 073 private final AtomicReference<CompletableFuture<AsyncConnection>> future = 074 new AtomicReference<>(); 075 076 private CompletableFuture<AsyncConnection> getConn() { 077 CompletableFuture<AsyncConnection> f = future.get(); 078 if (f != null) { 079 return f; 080 } 081 for (;;) { 082 if (future.compareAndSet(null, new CompletableFuture<>())) { 083 CompletableFuture<AsyncConnection> toComplete = future.get(); 084 addListener(ConnectionFactory.createAsyncConnection(getConf()),(conn, error) -> { 085 if (error != null) { 086 toComplete.completeExceptionally(error); 087 // we need to reset the future holder so we will get a chance to recreate an async 088 // connection at next try. 089 future.set(null); 090 return; 091 } 092 toComplete.complete(conn); 093 }); 094 return toComplete; 095 } else { 096 f = future.get(); 097 if (f != null) { 098 return f; 099 } 100 } 101 } 102 } 103 104 @edu.umd.cs.findbugs.annotations.SuppressWarnings(value = "NP_NONNULL_PARAM_VIOLATION", 105 justification = "it is valid to pass NULL to CompletableFuture#completedFuture") 106 private CompletableFuture<Void> closeConn() { 107 CompletableFuture<AsyncConnection> f = future.get(); 108 if (f == null) { 109 return CompletableFuture.completedFuture(null); 110 } 111 CompletableFuture<Void> closeFuture = new CompletableFuture<>(); 112 addListener(f, (conn, error) -> { 113 if (error == null) { 114 IOUtils.closeQuietly(conn); 115 } 116 closeFuture.complete(null); 117 }); 118 return closeFuture; 119 } 120 121 private byte[] getKey(int i) { 122 return Bytes.toBytes(String.format("%08x", i)); 123 } 124 125 @Override 126 public int run(String[] args) throws Exception { 127 if (args.length < 1 || args.length > 2) { 128 System.out.println("Usage: " + this.getClass().getName() + " tableName [num_operations]"); 129 return -1; 130 } 131 TableName tableName = TableName.valueOf(args[0]); 132 int numOps = args.length > 1 ? Integer.parseInt(args[1]) : DEFAULT_NUM_OPS; 133 ExecutorService threadPool = Executors.newFixedThreadPool(THREAD_POOL_SIZE, 134 new ThreadFactoryBuilder().setNameFormat("AsyncClientExample-pool-%d").setDaemon(true) 135 .setUncaughtExceptionHandler(Threads.LOGGING_EXCEPTION_HANDLER).build()); 136 // We use AsyncTable here so we need to provide a separated thread pool. RawAsyncTable does not 137 // need a thread pool and may have a better performance if you use it correctly as it can save 138 // some context switches. But if you use RawAsyncTable incorrectly, you may have a very bad 139 // impact on performance so use it with caution. 140 CountDownLatch latch = new CountDownLatch(numOps); 141 IntStream.range(0, numOps).forEach(i -> { 142 CompletableFuture<AsyncConnection> future = getConn(); 143 addListener(future, (conn, error) -> { 144 if (error != null) { 145 LOG.warn("failed to get async connection for " + i, error); 146 latch.countDown(); 147 return; 148 } 149 AsyncTable<?> table = conn.getTable(tableName, threadPool); 150 addListener(table.put(new Put(getKey(i)).addColumn(FAMILY, QUAL, Bytes.toBytes(i))), 151 (putResp, putErr) -> { 152 if (putErr != null) { 153 LOG.warn("put failed for " + i, putErr); 154 latch.countDown(); 155 return; 156 } 157 LOG.info("put for " + i + " succeeded, try getting"); 158 addListener(table.get(new Get(getKey(i))), (result, getErr) -> { 159 if (getErr != null) { 160 LOG.warn("get failed for " + i); 161 latch.countDown(); 162 return; 163 } 164 if (result.isEmpty()) { 165 LOG.warn("get failed for " + i + ", server returns empty result"); 166 } else if (!result.containsColumn(FAMILY, QUAL)) { 167 LOG.warn("get failed for " + i + ", the result does not contain " + 168 Bytes.toString(FAMILY) + ":" + Bytes.toString(QUAL)); 169 } else { 170 int v = Bytes.toInt(result.getValue(FAMILY, QUAL)); 171 if (v != i) { 172 LOG.warn("get failed for " + i + ", the value of " + Bytes.toString(FAMILY) + 173 ":" + Bytes.toString(QUAL) + " is " + v + ", exected " + i); 174 } else { 175 LOG.info("get for " + i + " succeeded"); 176 } 177 } 178 latch.countDown(); 179 }); 180 }); 181 }); 182 }); 183 latch.await(); 184 closeConn().get(); 185 return 0; 186 } 187 188 public static void main(String[] args) throws Exception { 189 ToolRunner.run(new AsyncClientExample(), args); 190 } 191}