Time for action – creating the source code

We'll now see the source code to implement our graph traversal. Because the code is lengthy, we'll break it into multiple steps; obviously they should all be together in a single source file.

1. Create the following as GraphPath.java with these imports:

   import java.io.* ;
   
   import org.apache.hadoop.conf.Configuration;
   import org.apache.hadoop.fs.Path;
   import org.apache.hadoop.io.Text;
   import org.apache.hadoop.mapreduce.Job;
   import org.apache.hadoop.mapreduce.*;
   import org.apache.hadoop.mapreduce.lib.input.*;
   import org.apache.hadoop.mapreduce.lib.output.*;
   
   public class GraphPath
   {

2. Create an inner class to hold an object-oriented representation of a node:

   // Inner class to represent a node
       public static class Node
       {
   // The integer node id
           private String id ;
   // The ids of all nodes this node has a path to
           private String neighbours ;
   // The distance of this node to the starting node
           private int distance ;
   // The current node...