public class MyMapper2 extends Mapper<LongWritable, Text,Text,LongWritable> {

    @Override
    protected void map(LongWritable key, Text value, Context context) throws IOException, InterruptedException {
        super.map(key, value, context);
    }
}

Called once for each key/value pair in the input split. Most applications should override this, but the default is the identity function.

  @SuppressWarnings("unchecked")
  protected void map(KEYIN key, VALUEIN value, 
                     Context context) throws IOException, InterruptedException {
    context.write((KEYOUT) key, (VALUEOUT) value);
  }

The Context passed on to the {@link Mapper} implementations.

  public abstract class Context
    implements MapContext<KEYIN,VALUEIN,KEYOUT,VALUEOUT> {
  }

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.

import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.classification.InterfaceStability;

/**
 * The context that is given to the {@link Mapper}.
 * @param <KEYIN> the key input type to the Mapper
 * @param <VALUEIN> the value input type to the Mapper
 * @param <KEYOUT> the key output type from the Mapper
 * @param <VALUEOUT> the value output type from the Mapper
 */
@InterfaceAudience.Public
@InterfaceStability.Evolving
public interface MapContext<KEYIN,VALUEIN,KEYOUT,VALUEOUT> 
  extends TaskInputOutputContext<KEYIN,VALUEIN,KEYOUT,VALUEOUT> {

  /**
   * Get the input split for this map.
   */
  public InputSplit getInputSplit();
  
}