[120] | 1 | /** |
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| 2 | * Licensed to the Apache Software Foundation (ASF) under one |
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| 3 | * or more contributor license agreements. See the NOTICE file |
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| 4 | * distributed with this work for additional information |
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| 5 | * regarding copyright ownership. The ASF licenses this file |
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| 6 | * to you under the Apache License, Version 2.0 (the |
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| 7 | * "License"); you may not use this file except in compliance |
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| 8 | * with the License. You may obtain a copy of the License at |
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| 9 | * |
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| 10 | * http://www.apache.org/licenses/LICENSE-2.0 |
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| 11 | * |
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| 12 | * Unless required by applicable law or agreed to in writing, software |
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| 13 | * distributed under the License is distributed on an "AS IS" BASIS, |
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| 14 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
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| 15 | * See the License for the specific language governing permissions and |
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| 16 | * limitations under the License. |
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| 17 | */ |
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| 18 | |
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| 19 | package org.apache.hadoop.mapreduce; |
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| 20 | |
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| 21 | import java.io.IOException; |
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| 22 | |
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| 23 | import org.apache.hadoop.conf.Configuration; |
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| 24 | import org.apache.hadoop.util.Progressable; |
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| 25 | |
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| 26 | /** |
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| 27 | * A context object that allows input and output from the task. It is only |
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| 28 | * supplied to the {@link Mapper} or {@link Reducer}. |
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| 29 | * @param <KEYIN> the input key type for the task |
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| 30 | * @param <VALUEIN> the input value type for the task |
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| 31 | * @param <KEYOUT> the output key type for the task |
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| 32 | * @param <VALUEOUT> the output value type for the task |
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| 33 | */ |
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| 34 | public abstract class TaskInputOutputContext<KEYIN,VALUEIN,KEYOUT,VALUEOUT> |
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| 35 | extends TaskAttemptContext implements Progressable { |
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| 36 | private RecordWriter<KEYOUT,VALUEOUT> output; |
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| 37 | private StatusReporter reporter; |
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| 38 | private OutputCommitter committer; |
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| 39 | |
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| 40 | public TaskInputOutputContext(Configuration conf, TaskAttemptID taskid, |
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| 41 | RecordWriter<KEYOUT,VALUEOUT> output, |
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| 42 | OutputCommitter committer, |
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| 43 | StatusReporter reporter) { |
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| 44 | super(conf, taskid); |
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| 45 | this.output = output; |
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| 46 | this.reporter = reporter; |
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| 47 | this.committer = committer; |
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| 48 | } |
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| 49 | |
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| 50 | /** |
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| 51 | * Advance to the next key, value pair, returning null if at end. |
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| 52 | * @return the key object that was read into, or null if no more |
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| 53 | */ |
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| 54 | public abstract |
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| 55 | boolean nextKeyValue() throws IOException, InterruptedException; |
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| 56 | |
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| 57 | /** |
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| 58 | * Get the current key. |
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| 59 | * @return the current key object or null if there isn't one |
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| 60 | * @throws IOException |
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| 61 | * @throws InterruptedException |
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| 62 | */ |
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| 63 | public abstract |
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| 64 | KEYIN getCurrentKey() throws IOException, InterruptedException; |
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| 65 | |
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| 66 | /** |
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| 67 | * Get the current value. |
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| 68 | * @return the value object that was read into |
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| 69 | * @throws IOException |
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| 70 | * @throws InterruptedException |
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| 71 | */ |
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| 72 | public abstract VALUEIN getCurrentValue() throws IOException, |
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| 73 | InterruptedException; |
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| 74 | |
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| 75 | /** |
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| 76 | * Generate an output key/value pair. |
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| 77 | */ |
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| 78 | public void write(KEYOUT key, VALUEOUT value |
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| 79 | ) throws IOException, InterruptedException { |
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| 80 | output.write(key, value); |
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| 81 | } |
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| 82 | |
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| 83 | public Counter getCounter(Enum<?> counterName) { |
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| 84 | return reporter.getCounter(counterName); |
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| 85 | } |
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| 86 | |
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| 87 | public Counter getCounter(String groupName, String counterName) { |
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| 88 | return reporter.getCounter(groupName, counterName); |
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| 89 | } |
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| 90 | |
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| 91 | @Override |
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| 92 | public void progress() { |
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| 93 | reporter.progress(); |
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| 94 | } |
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| 95 | |
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| 96 | @Override |
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| 97 | public void setStatus(String status) { |
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| 98 | reporter.setStatus(status); |
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| 99 | } |
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| 100 | |
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| 101 | public OutputCommitter getOutputCommitter() { |
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| 102 | return committer; |
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| 103 | } |
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| 104 | } |
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