OutputHandler.java
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上传日期:2018-01-08
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文件大小:5k
- /**
- * 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.pipes;
- import java.io.IOException;
- import java.util.ArrayList;
- import java.util.HashMap;
- import java.util.List;
- import java.util.Map;
- import org.apache.hadoop.io.FloatWritable;
- import org.apache.hadoop.io.NullWritable;
- import org.apache.hadoop.io.Writable;
- import org.apache.hadoop.io.WritableComparable;
- import org.apache.hadoop.mapred.Counters;
- import org.apache.hadoop.mapred.OutputCollector;
- import org.apache.hadoop.mapred.RecordReader;
- import org.apache.hadoop.mapred.Reporter;
- /**
- * Handles the upward (C++ to Java) messages from the application.
- */
- class OutputHandler<K extends WritableComparable,
- V extends Writable>
- implements UpwardProtocol<K, V> {
-
- private Reporter reporter;
- private OutputCollector<K, V> collector;
- private float progressValue = 0.0f;
- private boolean done = false;
- private Throwable exception = null;
- RecordReader<FloatWritable,NullWritable> recordReader = null;
- private Map<Integer, Counters.Counter> registeredCounters =
- new HashMap<Integer, Counters.Counter>();
- /**
- * Create a handler that will handle any records output from the application.
- * @param collector the "real" collector that takes the output
- * @param reporter the reporter for reporting progress
- */
- public OutputHandler(OutputCollector<K, V> collector, Reporter reporter,
- RecordReader<FloatWritable,NullWritable> recordReader) {
- this.reporter = reporter;
- this.collector = collector;
- this.recordReader = recordReader;
- }
- /**
- * The task output a normal record.
- */
- public void output(K key, V value) throws IOException {
- collector.collect(key, value);
- }
- /**
- * The task output a record with a partition number attached.
- */
- public void partitionedOutput(int reduce, K key,
- V value) throws IOException {
- PipesPartitioner.setNextPartition(reduce);
- collector.collect(key, value);
- }
- /**
- * Update the status message for the task.
- */
- public void status(String msg) {
- reporter.setStatus(msg);
- }
- private FloatWritable progressKey = new FloatWritable(0.0f);
- private NullWritable nullValue = NullWritable.get();
- /**
- * Update the amount done and call progress on the reporter.
- */
- public void progress(float progress) throws IOException {
- progressValue = progress;
- reporter.progress();
-
- if (recordReader != null) {
- progressKey.set(progress);
- recordReader.next(progressKey, nullValue);
- }
- }
- /**
- * The task finished successfully.
- */
- public void done() throws IOException {
- synchronized (this) {
- done = true;
- notify();
- }
- }
- /**
- * Get the current amount done.
- * @return a float between 0.0 and 1.0
- */
- public float getProgress() {
- return progressValue;
- }
- /**
- * The task failed with an exception.
- */
- public void failed(Throwable e) {
- synchronized (this) {
- exception = e;
- notify();
- }
- }
- /**
- * Wait for the task to finish or abort.
- * @return did the task finish correctly?
- * @throws Throwable
- */
- public synchronized boolean waitForFinish() throws Throwable {
- while (!done && exception == null) {
- wait();
- }
- if (exception != null) {
- throw exception;
- }
- return done;
- }
- public void registerCounter(int id, String group, String name) throws IOException {
- Counters.Counter counter = reporter.getCounter(group, name);
- registeredCounters.put(id, counter);
- }
- public void incrementCounter(int id, long amount) throws IOException {
- if (id < registeredCounters.size()) {
- Counters.Counter counter = registeredCounters.get(id);
- counter.increment(amount);
- } else {
- throw new IOException("Invalid counter with id: " + id);
- }
- }
- }