Java tutorial
/** * 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.mapreduce; import java.io.IOException; import org.apache.hadoop.classification.InterfaceAudience; import org.apache.hadoop.classification.InterfaceStability; import org.apache.hadoop.classification.InterfaceStability.Evolving; import org.apache.hadoop.mapred.SplitLocationInfo; import org.apache.hadoop.mapreduce.InputFormat; import org.apache.hadoop.mapreduce.Mapper; import org.apache.hadoop.mapreduce.RecordReader; /** * <code>InputSplit</code> represents the data to be processed by an * individual {@link Mapper}. * * <p>Typically, it presents a byte-oriented view on the input and is the * responsibility of {@link RecordReader} of the job to process this and present * a record-oriented view. * * @see InputFormat * @see RecordReader */ @InterfaceAudience.Public @InterfaceStability.Stable public abstract class InputSplit { /** * Get the size of the split, so that the input splits can be sorted by size. * @return the number of bytes in the split * @throws IOException * @throws InterruptedException */ public abstract long getLength() throws IOException, InterruptedException; /** * Get the list of nodes by name where the data for the split would be local. * The locations do not need to be serialized. * * @return a new array of the node nodes. * @throws IOException * @throws InterruptedException */ public abstract String[] getLocations() throws IOException, InterruptedException; /** * Gets info about which nodes the input split is stored on and how it is * stored at each location. * * @return list of <code>SplitLocationInfo</code>s describing how the split * data is stored at each location. A null value indicates that all the * locations have the data stored on disk. * @throws IOException */ @Evolving public SplitLocationInfo[] getLocationInfo() throws IOException { return null; } }