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R3704/hadoop-2.3.0-src/hadoop-tools/hadoop-pipes/src/main/native/examples/impl/wordcount-simple.cc
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wordcount-simple.cc
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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.
*/
#include "hadoop/Pipes.hh"
#include "hadoop/TemplateFactory.hh"
#include "hadoop/StringUtils.hh"
const std::string WORDCOUNT = "WORDCOUNT";
const std::string INPUT_WORDS = "INPUT_WORDS";
const std::string OUTPUT_WORDS = "OUTPUT_WORDS";
class WordCountMap: public HadoopPipes::Mapper {
public:
HadoopPipes::TaskContext::Counter* inputWords;
WordCountMap(HadoopPipes::TaskContext& context) {
inputWords = context.getCounter(WORDCOUNT, INPUT_WORDS);
}
void map(HadoopPipes::MapContext& context) {
std::vector<std::string> words =
HadoopUtils::splitString(context.getInputValue(), " ");
for(unsigned int i=0; i < words.size(); ++i) {
context.emit(words[i], "1");
}
context.incrementCounter(inputWords, words.size());
}
};
class WordCountReduce: public HadoopPipes::Reducer {
public:
HadoopPipes::TaskContext::Counter* outputWords;
WordCountReduce(HadoopPipes::TaskContext& context) {
outputWords = context.getCounter(WORDCOUNT, OUTPUT_WORDS);
}
void reduce(HadoopPipes::ReduceContext& context) {
int sum = 0;
while (context.nextValue()) {
sum += HadoopUtils::toInt(context.getInputValue());
}
context.emit(context.getInputKey(), HadoopUtils::toString(sum));
context.incrementCounter(outputWords, 1);
}
};
int main(int argc, char *argv[]) {
return HadoopPipes::runTask(HadoopPipes::TemplateFactory<WordCountMap,
WordCountReduce>());
}
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