PipesMapRunner.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.mapred.pipes;
- import java.io.IOException;
- 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.JobConf;
- import org.apache.hadoop.mapred.MapRunner;
- import org.apache.hadoop.mapred.OutputCollector;
- import org.apache.hadoop.mapred.RecordReader;
- import org.apache.hadoop.mapred.Reporter;
- import org.apache.hadoop.mapred.SkipBadRecords;
- /**
- * An adaptor to run a C++ mapper.
- */
- class PipesMapRunner<K1 extends WritableComparable, V1 extends Writable,
- K2 extends WritableComparable, V2 extends Writable>
- extends MapRunner<K1, V1, K2, V2> {
- private JobConf job;
- /**
- * Get the new configuration.
- * @param job the job's configuration
- */
- public void configure(JobConf job) {
- this.job = job;
- //disable the auto increment of the counter. For pipes, no of processed
- //records could be different(equal or less) than the no of records input.
- SkipBadRecords.setAutoIncrMapperProcCount(job, false);
- }
- /**
- * Run the map task.
- * @param input the set of inputs
- * @param output the object to collect the outputs of the map
- * @param reporter the object to update with status
- */
- @SuppressWarnings("unchecked")
- public void run(RecordReader<K1, V1> input, OutputCollector<K2, V2> output,
- Reporter reporter) throws IOException {
- Application<K1, V1, K2, V2> application = null;
- try {
- RecordReader<FloatWritable, NullWritable> fakeInput =
- (!Submitter.getIsJavaRecordReader(job) &&
- !Submitter.getIsJavaMapper(job)) ?
- (RecordReader<FloatWritable, NullWritable>) input : null;
- application = new Application<K1, V1, K2, V2>(job, fakeInput, output,
- reporter,
- (Class<? extends K2>) job.getOutputKeyClass(),
- (Class<? extends V2>) job.getOutputValueClass());
- } catch (InterruptedException ie) {
- throw new RuntimeException("interrupted", ie);
- }
- DownwardProtocol<K1, V1> downlink = application.getDownlink();
- boolean isJavaInput = Submitter.getIsJavaRecordReader(job);
- downlink.runMap(reporter.getInputSplit(),
- job.getNumReduceTasks(), isJavaInput);
- boolean skipping = job.getBoolean("mapred.skip.on", false);
- try {
- if (isJavaInput) {
- // allocate key & value instances that are re-used for all entries
- K1 key = input.createKey();
- V1 value = input.createValue();
- downlink.setInputTypes(key.getClass().getName(),
- value.getClass().getName());
-
- while (input.next(key, value)) {
- // map pair to output
- downlink.mapItem(key, value);
- if(skipping) {
- //flush the streams on every record input if running in skip mode
- //so that we don't buffer other records surrounding a bad record.
- downlink.flush();
- }
- }
- downlink.endOfInput();
- }
- application.waitForFinish();
- } catch (Throwable t) {
- application.abort(t);
- } finally {
- application.cleanup();
- }
- }
-
- }