/**
w * 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.mahout.fpm.pfpgrowth;

import java.io.IOException;
import java.util.regex.Pattern;

import org.apache.hadoop.io.LongWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Mapper;
import org.apache.mahout.common.Parameters;

/**
 * 
 *  maps all items in a particular transaction like the way it is done in Hadoop
 * WordCount example
 * 
 */
public class ParallelCountingMapper extends Mapper<LongWritable,Text,Text,LongWritable> {
  
  private static final LongWritable ONE = new LongWritable(1);
  
  private Pattern splitter;
  
  @Override
  protected void map(LongWritable offset, Text input, Context context) throws IOException,
                                                                      InterruptedException {
    
    String[] items = splitter.split(input.toString());
    for (String item : items) {
      if (item.trim().length() == 0) {
        continue;
      }
      context.setStatus("Parallel Counting Mapper: " + item);
      context.write(new Text(item), ONE);
    }
  }
  
  @Override
  protected void setup(Context context) throws IOException, InterruptedException {
    super.setup(context);
    Parameters params = Parameters.fromString(context.getConfiguration().get(PFPGrowth.PFP_PARAMETERS, ""));
    splitter = Pattern.compile(params.get(PFPGrowth.SPLIT_PATTERN, PFPGrowth.SPLITTER.toString()));
  }
}
