TeraOutputFormat.java
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上传日期:2018-01-08
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- /**
- * 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.examples.terasort;
- import java.io.DataOutputStream;
- import java.io.IOException;
- import org.apache.hadoop.fs.FSDataOutputStream;
- import org.apache.hadoop.fs.FileSystem;
- import org.apache.hadoop.fs.Path;
- import org.apache.hadoop.io.Text;
- import org.apache.hadoop.mapred.JobConf;
- import org.apache.hadoop.mapred.RecordWriter;
- import org.apache.hadoop.mapred.TextOutputFormat;
- import org.apache.hadoop.util.Progressable;
- /**
- * A streamlined text output format that writes key, value, and "rn".
- */
- public class TeraOutputFormat extends TextOutputFormat<Text,Text> {
- static final String FINAL_SYNC_ATTRIBUTE = "terasort.final.sync";
- /**
- * Set the requirement for a final sync before the stream is closed.
- */
- public static void setFinalSync(JobConf conf, boolean newValue) {
- conf.setBoolean(FINAL_SYNC_ATTRIBUTE, newValue);
- }
- /**
- * Does the user want a final sync at close?
- */
- public static boolean getFinalSync(JobConf conf) {
- return conf.getBoolean(FINAL_SYNC_ATTRIBUTE, false);
- }
- static class TeraRecordWriter extends LineRecordWriter<Text,Text> {
- private static final byte[] newLine = "rn".getBytes();
- private boolean finalSync = false;
- public TeraRecordWriter(DataOutputStream out,
- JobConf conf) {
- super(out);
- finalSync = getFinalSync(conf);
- }
- public synchronized void write(Text key,
- Text value) throws IOException {
- out.write(key.getBytes(), 0, key.getLength());
- out.write(value.getBytes(), 0, value.getLength());
- out.write(newLine, 0, newLine.length);
- }
-
- public void close() throws IOException {
- if (finalSync) {
- ((FSDataOutputStream) out).sync();
- }
- super.close(null);
- }
- }
- public RecordWriter<Text,Text> getRecordWriter(FileSystem ignored,
- JobConf job,
- String name,
- Progressable progress
- ) throws IOException {
- Path dir = getWorkOutputPath(job);
- FileSystem fs = dir.getFileSystem(job);
- FSDataOutputStream fileOut = fs.create(new Path(dir, name), progress);
- return new TeraRecordWriter(fileOut, job);
- }
- }