TaggedInputSplit.java
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上传日期:2018-01-08
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文件大小:4k
- /**
- * 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.mapred.lib;
- import java.io.DataInput;
- import java.io.DataOutput;
- import java.io.IOException;
- import org.apache.hadoop.conf.Configurable;
- import org.apache.hadoop.conf.Configuration;
- import org.apache.hadoop.io.Text;
- import org.apache.hadoop.mapred.InputFormat;
- import org.apache.hadoop.mapred.InputSplit;
- import org.apache.hadoop.mapred.Mapper;
- import org.apache.hadoop.util.ReflectionUtils;
- /**
- * An {@link InputSplit} that tags another InputSplit with extra data for use by
- * {@link DelegatingInputFormat}s and {@link DelegatingMapper}s.
- */
- class TaggedInputSplit implements Configurable, InputSplit {
- private Class<? extends InputSplit> inputSplitClass;
- private InputSplit inputSplit;
- private Class<? extends InputFormat> inputFormatClass;
- private Class<? extends Mapper> mapperClass;
- private Configuration conf;
- public TaggedInputSplit() {
- // Default constructor.
- }
- /**
- * Creates a new TaggedInputSplit.
- *
- * @param inputSplit The InputSplit to be tagged
- * @param conf The configuration to use
- * @param inputFormatClass The InputFormat class to use for this job
- * @param mapperClass The Mapper class to use for this job
- */
- public TaggedInputSplit(InputSplit inputSplit, Configuration conf,
- Class<? extends InputFormat> inputFormatClass,
- Class<? extends Mapper> mapperClass) {
- this.inputSplitClass = inputSplit.getClass();
- this.inputSplit = inputSplit;
- this.conf = conf;
- this.inputFormatClass = inputFormatClass;
- this.mapperClass = mapperClass;
- }
- /**
- * Retrieves the original InputSplit.
- *
- * @return The InputSplit that was tagged
- */
- public InputSplit getInputSplit() {
- return inputSplit;
- }
- /**
- * Retrieves the InputFormat class to use for this split.
- *
- * @return The InputFormat class to use
- */
- public Class<? extends InputFormat> getInputFormatClass() {
- return inputFormatClass;
- }
- /**
- * Retrieves the Mapper class to use for this split.
- *
- * @return The Mapper class to use
- */
- public Class<? extends Mapper> getMapperClass() {
- return mapperClass;
- }
- public long getLength() throws IOException {
- return inputSplit.getLength();
- }
- public String[] getLocations() throws IOException {
- return inputSplit.getLocations();
- }
- @SuppressWarnings("unchecked")
- public void readFields(DataInput in) throws IOException {
- inputSplitClass = (Class<? extends InputSplit>) readClass(in);
- inputSplit = (InputSplit) ReflectionUtils
- .newInstance(inputSplitClass, conf);
- inputSplit.readFields(in);
- inputFormatClass = (Class<? extends InputFormat>) readClass(in);
- mapperClass = (Class<? extends Mapper>) readClass(in);
- }
- private Class<?> readClass(DataInput in) throws IOException {
- String className = Text.readString(in);
- try {
- return conf.getClassByName(className);
- } catch (ClassNotFoundException e) {
- throw new RuntimeException("readObject can't find class", e);
- }
- }
- public void write(DataOutput out) throws IOException {
- Text.writeString(out, inputSplitClass.getName());
- inputSplit.write(out);
- Text.writeString(out, inputFormatClass.getName());
- Text.writeString(out, mapperClass.getName());
- }
- public Configuration getConf() {
- return conf;
- }
- public void setConf(Configuration conf) {
- this.conf = conf;
- }
- }