hamr.core.general.mapper.GeneralMapper.java Source code

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Here is the source code for hamr.core.general.mapper.GeneralMapper.java

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/*
  Copyright (c) 2015, Yiju Wei. 
    
  HAMR is a Frame let you use annotations to describe and execute a MapReduce process.
    
  This program is free software; you can redistribute it and/or modify it under the terms
  of the GNU General Public License as published by the Free Software Foundation; version 2
  of the License.
    
  This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
  without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
  See the GNU General Public License for more details.
    
  You should have received a copy of the GNU General Public License along with this
  program; if not, write to the Free Software Foundation, Inc., 51 Franklin St, Fifth
  Floor, Boston, MA 02110-1301  USA
    
 */
package hamr.core.general.mapper;

import java.io.IOException;
import java.lang.reflect.InvocationTargetException;
import java.util.List;

import org.apache.hadoop.io.NullWritable;
import org.apache.hadoop.mapred.JobContext;
import org.apache.hadoop.mapreduce.Mapper;

import hamr.core.general.annotations.Generator;
import hamr.core.general.bean.AnnotedBean;
import hamr.core.general.keyGenerator.KeyGenerator;

public class GeneralMapper extends Mapper<Object, Object, AnnotedBean, NullWritable> {
    @SuppressWarnings({ "rawtypes", "unchecked" })
    @Override
    protected void map(Object key, Object value, Mapper.Context context) throws IOException, InterruptedException {
        Class<? extends KeyGenerator> kgClass = context.getConfiguration()
                .getClass(JobContext.MAP_OUTPUT_KEY_CLASS, null, AnnotedBean.class).getAnnotation(Generator.class)
                .keyGeneratorClass();
        KeyGenerator kg;
        try {
            kg = kgClass.getConstructor(Mapper.Context.class).newInstance(context);
            List<AnnotedBean> generated = kg.generate(key, value);
            if (generated != null) {
                for (int i = 0; i < generated.size(); i++) {
                    context.write(generated.get(i), NullWritable.get());
                }
            }
        } catch (InstantiationException | IllegalAccessException | IllegalArgumentException
                | InvocationTargetException | NoSuchMethodException | SecurityException e) {
            e.printStackTrace();
        }
    }

}