import java.io.IOException;
import org.apache.hadoop.io.IntWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Mapper;

public class CharacterCountMapper extends Mapper<Object, Text, Text, IntWritable> {
    private final static IntWritable one = new IntWritable(1);
    private Text character = new Text();

    @Override
    protected void map(Object key, Text value, Context context) throws IOException, InterruptedException {
        String line = value.toString().toLowerCase();
        for (char c : line.toCharArray()) {
            if (Character.isAlphabetic(c)) {
                character.set(String.valueOf(c));
                context.write(character, one);
            }
        }
    }
}