//********************************************************************
//  Zero.java       Author: Lewis and Loftus
//
//  Demonstrates an uncaught exception.
//********************************************************************

public class Zero
{
   //-----------------------------------------------------------------
   //  Deliberately divides by zero to produce an exception.
   //-----------------------------------------------------------------
   public static void main (String[] args)
   {
      int numerator = 10;
      int denominator = 0;

      System.out.println (numerator / denominator);

      System.out.println ("This text will not be printed.");
   }
}


//********************************************************************
//  Zero2.java
//
//  Demonstrates an uncaught exception with a longer call stack trace.
//********************************************************************

public class Zero2
{
   //-----------------------------------------------------------------
   //  Deliberately divides by zero to produce an exception.
   //-----------------------------------------------------------------
   public static void main (String[] args)
   {
      int numerator = 10;
      int denominator = 0;

	  illegal(numerator, denominator);

      System.out.println ("This text will not be printed either.");
   }
   
   public static void illegal (int num, int den)
   {
	  System.out.println (num / den);
	  System.out.println ("This text will not be printed.");
   }
}


//********************************************************************
//  ProductCodes.java
//
//  Demonstrates the use of a try-catch block.
//********************************************************************

import java.util.*;

public class ProductCodes
{
   //-----------------------------------------------------------------
   //  Counts the number of product codes (???0000??A...) that are
   //  entered with a zone of R and and district greater than 2000.
   //-----------------------------------------------------------------
   public static void main (String[] args)
   {
      String code;
      char zone;
      int district, valid = 0, banned = 0;
      Scanner scan = new Scanner(System.in);

      System.out.print ("Enter product code (XXX to quit): ");
      code = scan.nextLine();

      while (!code.equals ("XXX"))
      {
         try
         {
            zone = code.charAt(9);
            district = Integer.parseInt(code.substring(3, 7));
            valid++;
            if (zone == 'R' && district > 2000)
               banned++;
         }
         catch (StringIndexOutOfBoundsException exception)
         {
            System.out.println ("Improper code length: " + code);
         }
         catch (NumberFormatException exception)
         {
            System.out.println ("District is not numeric: " + code);
         }

         System.out.print ("Enter product code (XXX to quit): ");
         code = scan.nextLine();
      }

      System.out.println ("# of valid codes entered: " + valid);
      System.out.println ("# of banned codes entered: " + banned);
   }
}


//********************************************************************
//  WildernessIndex.java
//
//  Demonstrates exception propagation.
//********************************************************************

public class WildernessIndex
{
   static public void main (String[] args)
   {
      WorldZoom wildIndex = new WorldZoom();

      System.out.println("Picking a country...");
      wildIndex.theUS();

      System.out.println("\nPicking another country...");
      wildIndex.canada();

      System.out.println("\nDone.");
   }
}


//********************************************************************
//  WorldZoom.java
//
//  Demonstrates exception propagation.
//********************************************************************

class WorldZoom
{
   //-----------------------------------------------------------------
   //  Catches and handles the exception that is thrown in montreal.
   //-----------------------------------------------------------------
   public void canada()
   {
      System.out.println("Zooming in to Canada.");

      try
      {
         quebec();
      }
      catch (ArithmeticException problem)
      {
         System.out.println ();
         System.out.println ("The exception message is: " +
                             problem.getMessage());
         System.out.println ();
         System.out.println ("The call stack trace:");
         problem.printStackTrace();
         System.out.println ();
      }

      System.out.println("Zooming out of Canada.");
   }

   //-----------------------------------------------------------------
   //  Serves as an intermediate level.  The exception propagates
   //  through this method back to canada.
   //-----------------------------------------------------------------
   public void quebec()
   {
      System.out.println("Zooming in to Quebec.");
      montreal ();
      System.out.println("Zooming out of quebec.");
   }

   //-----------------------------------------------------------------
   //  Performs a calculation to produce an exception.  It is not
   //  caught and handled at this level.
   //-----------------------------------------------------------------
   public void montreal()
   {
      int numPeople = 3000000, numBears = 0;

      System.out.println("Zooming in to Montreal.");
      int result = numPeople / numBears;
      System.out.println("The wilderness index is: " + result);
      System.out.println("Zooming out of Montreal.");
   }
   
   public void theUS()
   {
      System.out.println("Zooming in to the US.");

      try
      {
         alaska();
      }
      catch (ArithmeticException problem)
      {
         System.out.println ();
         System.out.println ("The exception message is: " +
                             problem.getMessage());
         System.out.println ();
         System.out.println ("The call stack trace:");
         problem.printStackTrace();
         System.out.println ();
      }

      System.out.println("Zooming out of the US.");
   }

   public void alaska()
   {
      System.out.println("Zooming in to Alaska.");
      kodiak ();
      System.out.println("Zooming out of Alaska.");
   }

   public void kodiak()
   {
      int numPeople = 13000, numBears = 3000;

      System.out.println("Zooming in to kodiak island.");
      int result = numPeople / numBears;
      System.out.println("The wilderness index is: " + result);
      System.out.println("Zooming out of kodiak island.");
   }
}

//********************************************************************
//  Ball.java
//
//  Testing exception hierarchies
//********************************************************************
class Ball extends Exception {
}

//********************************************************************
//  BaseBall.java
//
//  Testing exception hierarchies
//********************************************************************
class BaseBall extends Ball {
}

//********************************************************************
//  FootBall.java
//
//  Testing exception hierarchies
//********************************************************************
class FootBall extends Ball {
}

//********************************************************************
//  LetsPlayCatch.java
//
//  Testing exception hierarchies
//********************************************************************

class LetsPlayCatch {

    private static FootBall ball = new FootBall();  //or Ball or BaseBall

    public static void main (String[] args)
    {
        int i = 0;
        while (i<100)
        {
            try {
                if (++i % 3 == 0)
                {
	               	System.out.println("Going for a long one...");
        			throw ball;
                }
                System.out.println("Try #" + i);
            }
            catch (Ball b) // or Exception or Throwable
            {
            	System.out.println("uummpphhh...I got it! I got it!");
            }
        }
    }
}


//********************************************************************
//  Professor.java
//
//  Represents an Professor, which is a type of prey
//********************************************************************

public class Professor extends Prey
{
	public Professor(String name, int weight)
	{
		super(name,weight);	
	}	
	
}

//********************************************************************
//  PredatorsAreNotEatenException.java
//
//  Represents an exceptional condition in which we are trying to
//  eat a Predator
//********************************************************************

public class PredatorsAreNotEatenException extends Exception
{
   //-----------------------------------------------------------------
   //  Sets up the exception object with a particular message.
   //-----------------------------------------------------------------
   public PredatorsAreNotEatenException (String message)
   {
      super (message);
   }
}

//********************************************************************
//  YouShouldNotTryToHaveYourProfessorEatenException.java
//
//  Represents an exceptional condition in which we are trying to
//  eat a Professor
//********************************************************************

public class YouShouldNotTryToHaveYourProfessorEatenException extends Exception
{
   //-----------------------------------------------------------------
   //  Sets up the exception object with a predefined message.
   //-----------------------------------------------------------------
   public YouShouldNotTryToHaveYourProfessorEatenException ()
   {
      super ("Having your professor eaten will not help you pass the final.");
   }
}

//********************************************************************
//  WhoYouShouldAndShouldNotEat.java 
//
//  Demonstrates the ability to define an exception via inheritance.
//********************************************************************

import java.util.Scanner;

public class WhoYouShouldAndShouldNotEat
{
   //-----------------------------------------------------------------
   //  Creates a checked exception and possibly throws it.
   //-----------------------------------------------------------------
   public static void main (String[] args) throws YouShouldNotTryToHaveYourProfessorEatenException,
   									PredatorsAreNotEatenException
   {
      PredatorsAreNotEatenException tooMuchRisk =
         new PredatorsAreNotEatenException ("We won't allow it, it's too dangerous.");

	  Scanner scan = new Scanner(System.in);

      int value;

      Animal [] whoEatsWho = new Animal [2]; //first one is eater, second one is eaten
      
      String [] message = {"Who do you want feed? ","Who do you want to be eaten? "};
	  
      for (int i = 0; i< whoEatsWho.length; i++)
      {
      	System.out.println ("\t1. Simba");
      	System.out.println ("\t2. Mamba");
      	System.out.println ("\t3. Chui");
      	System.out.println ("\t4. Fisi");
      	System.out.println ("\t5. Digidigi");
      	System.out.println ("\t6. Twiga");
      	System.out.println ("\t7. Yannick");
      	System.out.println ("\t8. Nobody");
	  	
		System.out.print (message[i]);
      	value = scan.nextInt();
      	
      	switch (value)
      	{
      		case 1:
      			whoEatsWho[i] = new Lion("Simba", 220, "Wildebeests, zebras, buffaloes, young elephants, rhinos, hippos, giraffes, warthogs, antelopes, hyenas, humans and even crocodiles",15.0);
				break;
			case 2:
				whoEatsWho[i] = new Predator ("Mamba",400,"Fish, antelopes, buffaloes, Wildebeests, zebras, and humans", 30.0);
				break;
			case 3:
				whoEatsWho[i] = new Predator ("Chui",60,"Baboons, zebras, hares, warthogs, antelopes and humans",15.0);
				break;
			case 4:
				whoEatsWho[i] = new Hyena ("Fisi", 80, "Wildebeests, humans, zebras, buffaloes, warthogs, antelopes, cheetahs, hyenas and almost anything", 8.0, true);
				break;
			case 5:
				whoEatsWho[i] = new Prey ("Digidigi",4);
				break;
			case 6:
				whoEatsWho[i] = new Prey ("Twiga",1350);
				break;
			case 7:
				whoEatsWho[i] = new Professor("Yannick",66);
				break;
		}
		if (whoEatsWho[i] != null)
		  System.out.println (whoEatsWho[i] + "\n-------------------------");
    }
      	
    if (whoEatsWho[1] instanceof Professor) //The only Preys we don't want to eat are Professors
    	throw new YouShouldNotTryToHaveYourProfessorEatenException();
    else if (whoEatsWho[1] instanceof Predator)  //We don't want to eat ANY Predators
    	throw tooMuchRisk;
    
    try 
    {    
    	double amount = whoEatsWho[0].feed((Prey)whoEatsWho[1]);  // polymorphic
    	System.out.println ("Fed: " + amount);
    }
    catch (NullPointerException problem)
    {
    	System.out.println ("You shouldn't be afraid to have somebody eat somebody.");
    }
    
   }
}


//********************************************************************
//  countries.dat
//********************************************************************
Canada;31147000;9970610
China;1277558000;9572900
Namibia;1726000;824300
Peru;25662000;1285200
Spain;39630000;504750


//********************************************************************
//  MyWorld.java
//
//  Demonstrates the use of a text file input stream.
//********************************************************************

import java.util.*;
import java.io.*;

public class MyWorld
{
   //-----------------------------------------------------------------
   //  Reads data about a list of countries from an input file,
   //  creating an array of Country objects, then prints them.
   //-----------------------------------------------------------------
   public static void main (String[] args)
   {
      final int MAX = 200;
      Country[] myWorld = new Country[MAX];
      String line, name, fileName="countries.dat";
      int count = 0;
      long population, area;

      try
      {
         Scanner fileScan = new Scanner (new File(fileName));

         while (fileScan.hasNext())
         {
         	line = fileScan.nextLine();
         	Scanner lineScan = new Scanner(line).useDelimiter(";");
            try
            {
               name = lineScan.next();
               population = lineScan.nextLong();	
               area = lineScan.nextLong();
               myWorld[count++] = new Country (name, population, area);
            }
            catch (NoSuchElementException exception)
            {
               System.out.println ("Error in input. Line ignored:");
               System.out.println (line);
            }
         }

         for (int i = 0; i < count; i++)
            System.out.println (myWorld[i]);
      }
      catch (FileNotFoundException exception)
      {
         System.out.println ("The file " + fileName + " was not found.");
      }
   }
}


//********************************************************************
//  Country.java
//
//  Represents an country in the world.
//********************************************************************

import java.io.*;

public class Country
{
   private String name;
   private long population; // number of people
   private long area;       // geographical area

   //-----------------------------------------------------------------
   //  Sets up this country with the specified information.
   //-----------------------------------------------------------------
   public Country (String countryName, long numPeople, long size)
   {
      name = countryName;
      population = numPeople;
      area = size;
   }

   //-----------------------------------------------------------------
   //  Returns information about this country as a string.
   //-----------------------------------------------------------------
   public String toString()
   {
      return name + ": " + population + " people on " + area + " sqKms is " +
             (population / area) + " people per sqkm";
   }

   //-----------------------------------------------------------------
   //  Append country information to file fileName.
   //  Pass checked IOException handling to calling method.
   //-----------------------------------------------------------------   
   public void addToFile(String fileName) throws IOException
   {
      FileWriter fw = new FileWriter (fileName,true); //true for appending
      BufferedWriter bw = new BufferedWriter (fw);
      PrintWriter outFile = new PrintWriter (bw);

      outFile.println (name + ";" + population + ";" + area);

      outFile.close();
   }
}