TERM 2 MAGPIE3

/**
 * A program to carry on conversations with a human user.
 * This version:
 * <ul><li>
 *    Uses advanced search for keywords
 * </li></ul>
 *
 * @author Laurie White
 * @version April 2012
 */
public class Magpie3
{
 /**
  * Get a default greeting
  *
  * @return a greeting
  */
 public String getGreeting()
 {
  return "Hello, let's talk.";
 }

 /**
  * Gives a response to a user statement
  *
  * @param statement
  *            the user statement
  * @return a response based on the rules given
  */
 public String getResponse(String statement)
 {
  String response = "";
  if (statement.length() == 0)
  {
   response = "Say something, please.";
  }
  else if (findKeyword(statement, "no") >= 0)
  {
   response = "Why so negative?";
  }
  else if (findKeyword(statement, "mother") >= 0
    || findKeyword(statement, "father") >= 0
    || findKeyword(statement, "sister") >= 0
    || findKeyword(statement, "brother") >= 0)
  {
   response = "Tell me more about your family.";
  }

  // Change what is in the red then delete this line.
  else if (findKeyword(statement,"dog") >= 0
    || findKeyword(statement,"cat") >= 0
    || findKeyword(statement,"hampster") >= 0
    || findKeyword(statement,"ferret") >= 0)
  {
   response = "Tell me more about your pets.";
  }
  // Just the stuff between these two comments. Delete
  // Change what is in the red then delete this line.
  else if (findKeyword(statement,"Davis") >= 0
    || findKeyword(statement,"Horton") >= 0)
  {
   response = "What teachers are those?";
  }
  // Just the stuff between these two comments. Delete
  // Change what is in the red then delete this line.
  else if (statement.trim().length() == 0)
  {
   response = "Only quite?";
  }
  // Just the stuff between these two comments. Delete
  // Change what is in the red then delete this line.
  else if (findKeyword(statement,"sailing") >= 0
          || findKeyword(statement,"sail") >= 0
          || findKeyword(statement,"boat") >= 0)
  {
   response = "Do you like sailing too?";
  }
  // Just the stuff between these two comments. Delete
  // Change what is in the red then delete this line.
  else if (statement.indexOf("sailing") >= 0
          || statement.indexOf("sail") >= 0
          || statement.indexOf("boat") >= 0)
  {
   response = "Do you like sailing too?";
  }
  // Just the stuff between these two comments. Delete

  else
  {
   response = getRandomResponse();
  }
  return response;
 }

 /**
  * Search for one word in phrase. The search is not case
  * sensitive. This method will check that the given goal
  * is not a substring of a longer string (so, for
  * example, "I know" does not contain "no").
  *
  * @param statement
  *            the string to search
  * @param goal
  *            the string to search for
  * @param startPos
  *            the character of the string to begin the
  *            search at
  * @return the index of the first occurrence of goal in
  *         statement or -1 if it's not found
  */
 private int findKeyword(String statement, String goal,
   int startPos)
 {
  String phrase = statement.trim();
  // The only change to incorporate the startPos is in
  // the line below
  int psn = phrase.toLowerCase().indexOf(
    goal.toLowerCase(), startPos);

  // Refinement--make sure the goal isn't part of a
  // word
  while (psn >= 0)
  {
   // Find the string of length 1 before and after
   // the word
   String before = " ", after = " ";
   if (psn > 0)
   {
    before = phrase.substring(psn - 1, psn)
      .toLowerCase();
   }
   if (psn + goal.length() < phrase.length())
   {
    after = phrase.substring(
      psn + goal.length(),
      psn + goal.length() + 1)
      .toLowerCase();
   }

   // If before and after aren't letters, we've
   // found the word
   if (((before.compareTo("a") < 0) || (before
     .compareTo("z") > 0)) // before is not a
           // letter
     && ((after.compareTo("a") < 0) || (after
       .compareTo("z") > 0)))
   {
    return psn;
   }

   // The last position didn't work, so let's find
   // the next, if there is one.
   psn = phrase.indexOf(goal.toLowerCase(),
     psn + 1);

  }

  return -1;
 }

 /**
  * Search for one word in phrase. The search is not case
  * sensitive. This method will check that the given goal
  * is not a substring of a longer string (so, for
  * example, "I know" does not contain "no"). The search
  * begins at the beginning of the string.
  *
  * @param statement
  *            the string to search
  * @param goal
  *            the string to search for
  * @return the index of the first occurrence of goal in
  *         statement or -1 if it's not found
  */
 private int findKeyword(String statement, String goal)
 {
  return findKeyword(statement, goal, 0);
 }

 /**
  * Pick a default response to use if nothing else fits.
  *
  * @return a non-committal string
  */
 private String getRandomResponse()
 {
  final int NUMBER_OF_RESPONSES = 4;
  double r = Math.random();
  int whichResponse = (int) (r * NUMBER_OF_RESPONSES);
  String response = "";

  if (whichResponse == 0)
  {
   response = "Interesting, tell me more.";
  }
  else if (whichResponse == 1)
  {
   response = "Hmmm.";
  }
  else if (whichResponse == 2)
  {
   response = "Do you really think so?";
  }
  else if (whichResponse == 3)
  {
   response = "You don't say.";
  }

  return response;
 }

}