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| <pre><span class="source-line-no">001</span><span id="line-1">/*</span> |
| <span class="source-line-no">002</span><span id="line-2"> * Licensed to the Apache Software Foundation (ASF) under one</span> |
| <span class="source-line-no">003</span><span id="line-3"> * or more contributor license agreements. See the NOTICE file</span> |
| <span class="source-line-no">004</span><span id="line-4"> * distributed with this work for additional information</span> |
| <span class="source-line-no">005</span><span id="line-5"> * regarding copyright ownership. The ASF licenses this file</span> |
| <span class="source-line-no">006</span><span id="line-6"> * to you under the Apache License, Version 2.0 (the</span> |
| <span class="source-line-no">007</span><span id="line-7"> * "License"); you may not use this file except in compliance</span> |
| <span class="source-line-no">008</span><span id="line-8"> * with the License. You may obtain a copy of the License at</span> |
| <span class="source-line-no">009</span><span id="line-9"> *</span> |
| <span class="source-line-no">010</span><span id="line-10"> * http://www.apache.org/licenses/LICENSE-2.0</span> |
| <span class="source-line-no">011</span><span id="line-11"> *</span> |
| <span class="source-line-no">012</span><span id="line-12"> * Unless required by applicable law or agreed to in writing, software</span> |
| <span class="source-line-no">013</span><span id="line-13"> * distributed under the License is distributed on an "AS IS" BASIS,</span> |
| <span class="source-line-no">014</span><span id="line-14"> * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.</span> |
| <span class="source-line-no">015</span><span id="line-15"> * See the License for the specific language governing permissions and</span> |
| <span class="source-line-no">016</span><span id="line-16"> * limitations under the License.</span> |
| <span class="source-line-no">017</span><span id="line-17"> */</span> |
| <span class="source-line-no">018</span><span id="line-18">package org.apache.hadoop.hbase.mapreduce;</span> |
| <span class="source-line-no">019</span><span id="line-19"></span> |
| <span class="source-line-no">020</span><span id="line-20">import java.io.DataInput;</span> |
| <span class="source-line-no">021</span><span id="line-21">import java.io.DataOutput;</span> |
| <span class="source-line-no">022</span><span id="line-22">import java.util.ArrayList;</span> |
| <span class="source-line-no">023</span><span id="line-23">import java.util.List;</span> |
| <span class="source-line-no">024</span><span id="line-24">import org.apache.hadoop.conf.Configuration;</span> |
| <span class="source-line-no">025</span><span id="line-25">import org.apache.hadoop.io.NullWritable;</span> |
| <span class="source-line-no">026</span><span id="line-26">import org.apache.hadoop.io.Writable;</span> |
| <span class="source-line-no">027</span><span id="line-27">import org.apache.hadoop.mapreduce.InputFormat;</span> |
| <span class="source-line-no">028</span><span id="line-28">import org.apache.hadoop.mapreduce.InputSplit;</span> |
| <span class="source-line-no">029</span><span id="line-29">import org.apache.hadoop.mapreduce.JobContext;</span> |
| <span class="source-line-no">030</span><span id="line-30">import org.apache.hadoop.mapreduce.RecordReader;</span> |
| <span class="source-line-no">031</span><span id="line-31">import org.apache.hadoop.mapreduce.TaskAttemptContext;</span> |
| <span class="source-line-no">032</span><span id="line-32"></span> |
| <span class="source-line-no">033</span><span id="line-33">/**</span> |
| <span class="source-line-no">034</span><span id="line-34"> * Input format that creates a configurable number of map tasks each provided with a single row of</span> |
| <span class="source-line-no">035</span><span id="line-35"> * NullWritables. This can be useful when trying to write mappers which don't have any real input</span> |
| <span class="source-line-no">036</span><span id="line-36"> * (eg when the mapper is simply producing random data as output)</span> |
| <span class="source-line-no">037</span><span id="line-37"> */</span> |
| <span class="source-line-no">038</span><span id="line-38">public class NMapInputFormat extends InputFormat<NullWritable, NullWritable> {</span> |
| <span class="source-line-no">039</span><span id="line-39"> private static final String NMAPS_KEY = "nmapinputformat.num.maps";</span> |
| <span class="source-line-no">040</span><span id="line-40"></span> |
| <span class="source-line-no">041</span><span id="line-41"> @Override</span> |
| <span class="source-line-no">042</span><span id="line-42"> public RecordReader<NullWritable, NullWritable> createRecordReader(InputSplit split,</span> |
| <span class="source-line-no">043</span><span id="line-43"> TaskAttemptContext tac) {</span> |
| <span class="source-line-no">044</span><span id="line-44"> return new SingleRecordReader<>(NullWritable.get(), NullWritable.get());</span> |
| <span class="source-line-no">045</span><span id="line-45"> }</span> |
| <span class="source-line-no">046</span><span id="line-46"></span> |
| <span class="source-line-no">047</span><span id="line-47"> @Override</span> |
| <span class="source-line-no">048</span><span id="line-48"> public List<InputSplit> getSplits(JobContext context) {</span> |
| <span class="source-line-no">049</span><span id="line-49"> int count = getNumMapTasks(context.getConfiguration());</span> |
| <span class="source-line-no">050</span><span id="line-50"> List<InputSplit> splits = new ArrayList<>(count);</span> |
| <span class="source-line-no">051</span><span id="line-51"> for (int i = 0; i < count; i++) {</span> |
| <span class="source-line-no">052</span><span id="line-52"> splits.add(new NullInputSplit());</span> |
| <span class="source-line-no">053</span><span id="line-53"> }</span> |
| <span class="source-line-no">054</span><span id="line-54"> return splits;</span> |
| <span class="source-line-no">055</span><span id="line-55"> }</span> |
| <span class="source-line-no">056</span><span id="line-56"></span> |
| <span class="source-line-no">057</span><span id="line-57"> public static void setNumMapTasks(Configuration conf, int numTasks) {</span> |
| <span class="source-line-no">058</span><span id="line-58"> conf.setInt(NMAPS_KEY, numTasks);</span> |
| <span class="source-line-no">059</span><span id="line-59"> }</span> |
| <span class="source-line-no">060</span><span id="line-60"></span> |
| <span class="source-line-no">061</span><span id="line-61"> public static int getNumMapTasks(Configuration conf) {</span> |
| <span class="source-line-no">062</span><span id="line-62"> return conf.getInt(NMAPS_KEY, 1);</span> |
| <span class="source-line-no">063</span><span id="line-63"> }</span> |
| <span class="source-line-no">064</span><span id="line-64"></span> |
| <span class="source-line-no">065</span><span id="line-65"> private static class NullInputSplit extends InputSplit implements Writable {</span> |
| <span class="source-line-no">066</span><span id="line-66"> @Override</span> |
| <span class="source-line-no">067</span><span id="line-67"> public long getLength() {</span> |
| <span class="source-line-no">068</span><span id="line-68"> return 0;</span> |
| <span class="source-line-no">069</span><span id="line-69"> }</span> |
| <span class="source-line-no">070</span><span id="line-70"></span> |
| <span class="source-line-no">071</span><span id="line-71"> @Override</span> |
| <span class="source-line-no">072</span><span id="line-72"> public String[] getLocations() {</span> |
| <span class="source-line-no">073</span><span id="line-73"> return new String[] {};</span> |
| <span class="source-line-no">074</span><span id="line-74"> }</span> |
| <span class="source-line-no">075</span><span id="line-75"></span> |
| <span class="source-line-no">076</span><span id="line-76"> @Override</span> |
| <span class="source-line-no">077</span><span id="line-77"> public void readFields(DataInput in) {</span> |
| <span class="source-line-no">078</span><span id="line-78"> }</span> |
| <span class="source-line-no">079</span><span id="line-79"></span> |
| <span class="source-line-no">080</span><span id="line-80"> @Override</span> |
| <span class="source-line-no">081</span><span id="line-81"> public void write(DataOutput out) {</span> |
| <span class="source-line-no">082</span><span id="line-82"> }</span> |
| <span class="source-line-no">083</span><span id="line-83"> }</span> |
| <span class="source-line-no">084</span><span id="line-84"></span> |
| <span class="source-line-no">085</span><span id="line-85"> private static class SingleRecordReader<K, V> extends RecordReader<K, V> {</span> |
| <span class="source-line-no">086</span><span id="line-86"></span> |
| <span class="source-line-no">087</span><span id="line-87"> private final K key;</span> |
| <span class="source-line-no">088</span><span id="line-88"> private final V value;</span> |
| <span class="source-line-no">089</span><span id="line-89"> boolean providedKey = false;</span> |
| <span class="source-line-no">090</span><span id="line-90"></span> |
| <span class="source-line-no">091</span><span id="line-91"> SingleRecordReader(K key, V value) {</span> |
| <span class="source-line-no">092</span><span id="line-92"> this.key = key;</span> |
| <span class="source-line-no">093</span><span id="line-93"> this.value = value;</span> |
| <span class="source-line-no">094</span><span id="line-94"> }</span> |
| <span class="source-line-no">095</span><span id="line-95"></span> |
| <span class="source-line-no">096</span><span id="line-96"> @Override</span> |
| <span class="source-line-no">097</span><span id="line-97"> public void close() {</span> |
| <span class="source-line-no">098</span><span id="line-98"> }</span> |
| <span class="source-line-no">099</span><span id="line-99"></span> |
| <span class="source-line-no">100</span><span id="line-100"> @Override</span> |
| <span class="source-line-no">101</span><span id="line-101"> public K getCurrentKey() {</span> |
| <span class="source-line-no">102</span><span id="line-102"> return key;</span> |
| <span class="source-line-no">103</span><span id="line-103"> }</span> |
| <span class="source-line-no">104</span><span id="line-104"></span> |
| <span class="source-line-no">105</span><span id="line-105"> @Override</span> |
| <span class="source-line-no">106</span><span id="line-106"> public V getCurrentValue() {</span> |
| <span class="source-line-no">107</span><span id="line-107"> return value;</span> |
| <span class="source-line-no">108</span><span id="line-108"> }</span> |
| <span class="source-line-no">109</span><span id="line-109"></span> |
| <span class="source-line-no">110</span><span id="line-110"> @Override</span> |
| <span class="source-line-no">111</span><span id="line-111"> public float getProgress() {</span> |
| <span class="source-line-no">112</span><span id="line-112"> return 0;</span> |
| <span class="source-line-no">113</span><span id="line-113"> }</span> |
| <span class="source-line-no">114</span><span id="line-114"></span> |
| <span class="source-line-no">115</span><span id="line-115"> @Override</span> |
| <span class="source-line-no">116</span><span id="line-116"> public void initialize(InputSplit split, TaskAttemptContext tac) {</span> |
| <span class="source-line-no">117</span><span id="line-117"> }</span> |
| <span class="source-line-no">118</span><span id="line-118"></span> |
| <span class="source-line-no">119</span><span id="line-119"> @Override</span> |
| <span class="source-line-no">120</span><span id="line-120"> public boolean nextKeyValue() {</span> |
| <span class="source-line-no">121</span><span id="line-121"> if (providedKey) {</span> |
| <span class="source-line-no">122</span><span id="line-122"> return false;</span> |
| <span class="source-line-no">123</span><span id="line-123"> }</span> |
| <span class="source-line-no">124</span><span id="line-124"></span> |
| <span class="source-line-no">125</span><span id="line-125"> providedKey = true;</span> |
| <span class="source-line-no">126</span><span id="line-126"> return true;</span> |
| <span class="source-line-no">127</span><span id="line-127"> }</span> |
| <span class="source-line-no">128</span><span id="line-128"> }</span> |
| <span class="source-line-no">129</span><span id="line-129">}</span> |
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| </pre> |
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