Sample Code: GraphBot.java

package examples;
import becker.robots.*;

/** A GraphBot creates a "graph" with Thing objects.  The "data" are piles
    of things, all on consecutive intersections on a street.  The graph is
    constructed by spreading them out on consecutive intersections on the
    same avenue, one thing per intersection.  The GraphBot is assumed to
    start on the north-most pile of things, facing EAST, with an empty
    backpack. */
public class GraphBot extends Robot
{
   /** Construct a new graphing robot. */
   public GraphBot(City aCity, int anAvenue, int aStreet, int aDirection)
   {  super(aCity, anAvenue, aStreet, aDirection);
   }

   /** Make the graph. */
   public void makeGraph()
   {  while(this.isBesideThing())
      {  this.makeBar();
         this.moveToNextDataPile();
      }
   }

   /** Display the data by putting a thing on each intersection until we
   run out of things. */
   private void makeBar()
   {  this.getData();
      int barLength = this.countThingsInBackpack();
      this.putData(barLength);
      this.returnToBeginningOfBar(barLength);
   }

   /** Get the data for this bar of the graph by picking up all the things on this intersection. */
   private void getData()
   {  while(this.isBesideThing())
      {  this.pickThing();
      }
   }

   /** Put the data down to form a bar.
       @param barLength the length of this bar */
   private void putData(int barLength)
   {  this.move();
      for(int i=0; i<barLength-1; i++)
      {  this.putThing();
         this.move();
      }
      this.putThing();
   }

   /** Return to the beginning of the bar.
       @param barLength the length of this bar */
   private void returnToBeginningOfBar(int barLength)
   {  this.turnAround();
      for(int i=0; i<barLength; i++)
      {  this.move();
      }
   }

   /** Move to the next data pile. */
   private void moveToNextDataPile()
   {  this.turnLeft();
      this.move();
      this.turnLeft();
   }

   /** Turn around and face the opposite direction. */
   private void turnAround()
   {  this.turnLeft();
      this.turnLeft();
   }
}