| /** |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you under the Apache License, Version 2.0 (the |
| * "License"); you may not use this file except in compliance |
| * with the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| package org.apache.hadoop.fs; |
| |
| import java.io.IOException; |
| import java.net.InetAddress; |
| import org.apache.hadoop.conf.Configured; |
| import org.apache.hadoop.io.LongWritable; |
| import org.apache.hadoop.io.Text; |
| import org.apache.hadoop.mapred.*; |
| |
| /** |
| * Base mapper class for IO operations. |
| * <p> |
| * Two abstract method {@link #doIO(Reporter, String, long)} and |
| * {@link #collectStats(OutputCollector,String,long,Object)} should be |
| * overloaded in derived classes to define the IO operation and the |
| * statistics data to be collected by subsequent reducers. |
| * |
| */ |
| @SuppressWarnings("deprecation") |
| public abstract class IOMapperBase<T> extends Configured |
| implements Mapper<Text, LongWritable, Text, Text> { |
| |
| protected byte[] buffer; |
| protected int bufferSize; |
| protected FileSystem fs; |
| protected String hostName; |
| |
| public IOMapperBase() { |
| } |
| |
| public void configure(JobConf conf) { |
| setConf(conf); |
| try { |
| fs = FileSystem.get(conf); |
| } catch (Exception e) { |
| throw new RuntimeException("Cannot create file system.", e); |
| } |
| bufferSize = conf.getInt("test.io.file.buffer.size", 4096); |
| buffer = new byte[bufferSize]; |
| try { |
| hostName = InetAddress.getLocalHost().getHostName(); |
| } catch(Exception e) { |
| hostName = "localhost"; |
| } |
| } |
| |
| public void close() throws IOException { |
| } |
| |
| /** |
| * Perform io operation, usually read or write. |
| * |
| * @param reporter |
| * @param name file name |
| * @param value offset within the file |
| * @return object that is passed as a parameter to |
| * {@link #collectStats(OutputCollector,String,long,Object)} |
| * @throws IOException |
| */ |
| abstract T doIO(Reporter reporter, |
| String name, |
| long value) throws IOException; |
| |
| /** |
| * Collect stat data to be combined by a subsequent reducer. |
| * |
| * @param output |
| * @param name file name |
| * @param execTime IO execution time |
| * @param doIOReturnValue value returned by {@link #doIO(Reporter,String,long)} |
| * @throws IOException |
| */ |
| abstract void collectStats(OutputCollector<Text, Text> output, |
| String name, |
| long execTime, |
| T doIOReturnValue) throws IOException; |
| |
| /** |
| * Map file name and offset into statistical data. |
| * <p> |
| * The map task is to get the |
| * <tt>key</tt>, which contains the file name, and the |
| * <tt>value</tt>, which is the offset within the file. |
| * |
| * The parameters are passed to the abstract method |
| * {@link #doIO(Reporter,String,long)}, which performs the io operation, |
| * usually read or write data, and then |
| * {@link #collectStats(OutputCollector,String,long,Object)} |
| * is called to prepare stat data for a subsequent reducer. |
| */ |
| public void map(Text key, |
| LongWritable value, |
| OutputCollector<Text, Text> output, |
| Reporter reporter) throws IOException { |
| String name = key.toString(); |
| long longValue = value.get(); |
| |
| reporter.setStatus("starting " + name + " ::host = " + hostName); |
| |
| long tStart = System.currentTimeMillis(); |
| T statValue = doIO(reporter, name, longValue); |
| long tEnd = System.currentTimeMillis(); |
| long execTime = tEnd - tStart; |
| collectStats(output, name, execTime, statValue); |
| |
| reporter.setStatus("finished " + name + " ::host = " + hostName); |
| } |
| } |