Question

I have a MapReduce Java program which outputs a list of numbers as String as the final output. But the number is relatively long and consumes too much space. I want to convert each number to Long and store. How can I achieve this?

Answer 1

ArrayWritable can be extended as

public class LongArrayWritable extends ArrayWritable {
    public LongArrayWritable() {
        super(Text.class);
    }

    public LongArrayWritable(LongWritable[] values) {
        super(LongWritable.class, values);
    }
}

Also, a String can be converted into LongWritable as

String s = "123456";
new LongWritable((new Long(s)).longValue());