JustinThompsonHw9

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

public class JustinThompsonHw9
{	
	static LinkedList list;
	static final int MAX = 10; // using this for count.
	
	public static void main(String[] args) throws Exception
	{	
		list = new LinkedList();
		Scanner reader = new Scanner(System.in);
		displayMenu();
		int resp = reader.nextInt();
		while (resp != 0)
		{	switch (resp)
			{	case 1: enter1(reader); holdScreen(); break;
				case 2: showFirst2(); holdScreen(); break; 
				case 3: removeFirst3(); holdScreen(); break; 
				case 4: length4(); holdScreen(); break; 
				case 5: isFull5(); holdScreen(); break; 
				case 6: isEmpty6(); holdScreen(); break; 
				case 7: deleteAll7(); holdScreen(); break;
				case 8: displayAll8(); holdScreen(); break; 
				case 9: quit9(); holdScreen(); break; 
				case 10: deleteAllInSequence(); holdScreen(); break;
				default: System.out.println("Invalid entry. Please try again."); holdScreen(); break;
			}
			displayMenu();
			resp = reader.nextInt();
		}
	}

	public static void holdScreen() throws Exception
	{	
		Scanner reader = new Scanner(System.in);
		System.out.println("Press ENTER to continue . . .");
		String dummy = reader.nextLine();
	}

	public static void displayMenu()
	{	
		System.out.println("\n\n\n\n\n\n\tThings-To-Do List for Justin Thompson");
		System.out.println("--------------------------------------------------------------");
		System.out.println("\t1. Enter an item");
		System.out.println("\t2. Show the first entry");
		System.out.println("\t3. Remove the first entry ");
		System.out.println("\t4. Length of queue ");
		System.out.println("\t5. Is it full ");
		System.out.println("\t6. Is it empty ");		
		System.out.println("\t7. Empty the queue");

		System.out.println("\t8. Display queue contents ");
		System.out.println("\t9. Quit");
		System.out.println("--------------------------------------------------------------\n");
		
		System.out.println("\tExtra Options");
		
		System.out.println("--------------------------------------------------------------\n");
		System.out.println("\t10. Empty the queue sequentially");

		System.out.println("--------------------------------------------------------------\n");
		
		System.out.print("\tEnter your option: ");
	}

	public static void enter1(Scanner scan)
	{
		ListIterator iterator = list.listIterator();
		int count = 0;
		while(iterator.hasNext())
		{
			count++;
			iterator.next();
		}
		
		if (count != MAX)
		{
			addNode();
		}
		else
		{
			System.out.println("Your list is full. Please clear some items first.");
		}
	}
	
	public static void addNode()
	{
		Scanner reader = new Scanner(System.in);
		System.out.println("Enter the message:");
		String m = reader.nextLine();
		System.out.println("Enter the priority:");
		int p = reader.nextInt();
		Node newNode = new Node(m,p); // create the node
		ListIterator iterator = list.listIterator();
		boolean inserted = false;

		if (!(iterator.hasNext()))  // empty list
		{
			iterator.add(newNode);
		}
		else
		{  
			while (iterator.hasNext() && ! inserted) // insert in place
			{  
				Node temp = (Node)iterator.next();
				if (p < temp.getPriority())
				{  iterator.previous();
					iterator.add(newNode);
					inserted = true;
				}
			}
			if (!inserted) iterator.add(newNode);   // insert at end
		}
	}

	public static void showFirst2()
	{	
		ListIterator iterator = list.listIterator();
		if (iterator.hasNext())
		{
			System.out.println(iterator.next());
		}
		else
		{
			System.out.println("Your list is empty.");
		}
	}
	
	public static void removeFirst3()
	{	
		ListIterator iterator = list.listIterator();
		if (iterator.hasNext())
		{
			Object i = iterator.next(); // assign the pointer to a var for ref.
			System.out.println(i + " has been removed.");
			iterator.remove();
		}
		else
		{
			// List must be empty.
			System.out.println("Nothing to remove.");
		}
	}
	
	public static void length4()
	{	
		ListIterator iterator = list.listIterator();
		int count=0;
		while (iterator.hasNext())
		{	
			count++;
			iterator.next();
		}
		System.out.println("Your list contains: " + count + " items.");
	}
	
	public static void isFull5()
	{	
		ListIterator iterator = list.listIterator();
		int count=0;
		while (iterator.hasNext())
		{	
			count++;
			iterator.next();
		}
		
		if (count == MAX)
		{
			System.out.println("Your list is full.");
		}
		else if (count == 0)
		{
			System.out.println("Your list is empty.");
		}
		else if (count != MAX)
		{
			System.out.println("Your list is not full. List contains "
							   + count + " items.");
		}
	}

	public static void isEmpty6()
	{	
		ListIterator iterator = list.listIterator();		
		int count=0;
		while (iterator.hasNext())
		{
			count++;
			iterator.next();
		}
		
		if (count == 0)
		{
			System.out.println("Your list is empty.");
		}
		else
		{
			System.out.println("Your list is not empty. List contains "
							   + count + " items.");
		}
	}
	
	public static void deleteAll7()
	{	
		list = null;
		System.out.println("Your list has been emptied.");
	}
	
	public static void deleteAllInSequence()
	{
		ListIterator iterator = list.listIterator();
		int count=0;
		while (iterator.hasNext())
		{
			count++;
			Object i = iterator.next(); // assign the pointer to a var for ref.
			System.out.println(i + " has been removed.");
			iterator.remove();
		}
		
		if (count == 0)
		{
			System.out.println("Your list is empty.");
		}
	}
	
	public static void displayAll8()
	{	
		ListIterator iterator = list.listIterator();
		int count=0;
		while (iterator.hasNext())
		{
			count++;
			System.out.println(iterator.next());
		}
		
		if (count == 0)
		{
			System.out.println("Your list is empty.");
		}
	}
	
	public static void quit9()
	{	
		System.exit(1);
	}
}

class Node
{	
	private String message;
	private int priority;
	
	public Node(String m, int p)
	{	
		message = m;
		priority = p;
	}
	
	public int getPriority()
	{
		return priority;
	}
	
	public String toString()
	{	
		return "Message: " + message + ", Priority: " + priority;
	}
}