what is the right way to create a Writable class?

[juber patel]

Hello,

I am using Hadoop 0.20.2 with the new mapreduce API. I have a class
that will be used as a value to mapper/reducer. I have implemented
Writable as follows, but I am not sure this is the right way. Could
someone please tell me how to do it when some ints, some int[] and
other proper objects like java.util.BitSet are involved?

All the examples I have seen deal with native Writables or primitives.


/**
 *
 */

import java.io.DataInput;
import java.io.DataOutput;
import java.io.IOException;
import java.util.BitSet;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.io.ObjectWritable;
import org.apache.hadoop.io.Writable;

public class Data implements Writable
{
        
        public static Configuration conf;

        
        public BitSet b;

        public BitSet rb;

        public int[] c;

        public int bNullPosition;

        public int rbNullPosition;
        
        
        /**
         * writable must have empty constructor
         */
        public Data()
        {
                b = new BitSet();
                rb = new BitSet();
                                
        }

        public Data(BitSet b, BitSet rb, int[] c, int bNullPosition,
                        int rbNullPositionl)
        {
                this.b = b;
                this.rb = rb;
                this.c = c;
                this.bNullPosition = bNullPosition;
                this.rbNullPosition = rbNullPosition;
        }
        
        @Override
        public void readFields(DataInput in) throws IOException
        {
                ObjectWritable bWritable = new ObjectWritable(BitSet.class, b);
                bWritable.readFields(in);
                bWritable = new ObjectWritable(BitSet.class, rb);
                bWritable.readFields(in);
                bWritable = null;
                
                c = (int[]) ObjectWritable.readObject(in, conf);
                
                bNullPosition = in.readInt();
                rbNullPosition = in.readInt();
                
                
        }

        @Override
        public void write(DataOutput out) throws IOException
        {
                ObjectWritable bWritable = new ObjectWritable(BitSet.class, b);
                bWritable.write(out);
                bWritable = new ObjectWritable(BitSet.class, rb);
                bWritable.write(out);
                bWritable = null;
                
                ObjectWritable.writeObject(out, c, int[].class, conf);
                out.writeInt(bNullPosition);
                out.writeInt(rbNullPosition);
                
                        
        }
        
}