Nsryjdtyk

I want to display all items in a stack but it doesn't work.

Here is my Classes:

public class CommandFactory

{

    public Command getCommand(String type)

    {

        if(type.equalsIgnoreCase("c"))

        {

            return new CreateDVD();

        }

        //......Other commands

  }  

  return null;

}



public interface DVD

{

     int getDvdID();

     String getTitle();

     int getLength();

     int getNumAvailable();

     void setNumAvailable(int numAvailable);

     String toString();

} 



public class Movie implements DVD

{

    private int dvdID;

    private String title;

    private int length;

    private int numAvailable;

    private String director;



    public Movie(int dvdID, String title, int length, int numAvailable, String director)

    {

      //Constructor

    }



    public int getDvdID() { return dvdID; }



    //...getters and setters



    public String toString() 

    {

        return String.format("DVD InformationnID: %dnTitle: %snLength: %d minsnNumber of available copies: %dnDirector: %s", dvdID, title, length, numAvailable, director);

    }

}



public class CreateDVD implements Command

{

    public Stack<DVD> dvdStack = new Stack<>();

    private Stack<DVD> dvdUndoStack = new Stack<>();

    private DVD dvd;

    private DVDFactory dvdFactory = new DVDFactory();

    private Scanner kb = new Scanner(System.in);



    public void execute()

    {

        System.out.println("Please enter DVD type (mo=movie/mv=MV)");

        String type = kb.next();

        dvd = dvdFactory.getDVD(type);

        dvdStack.push(dvd);

    }

    //other methods 

}

The implementation below will only show the last item in the stack.

public class DVDHandler

{

        Stack<Command> unDoCommandStack = new Stack<>();

        Stack<Command> reDoCommandStack = new Stack<>();

        Stack<DVD> dvdStack = new Stack<>();

        CommandFactory commandFactory = new CommandFactory();

        boolean exit = false;



        public void run()

        {

            .

            .

            .

            Scanner kb = new Scanner(System.in);

            String input = kb.next();

            Command command = commandFactory.getCommand(input);

            if(command instanceof CreateDVD)

            {

                command.execute();

                dvdStack = ((CreateDVD) command).getDvdStack();

                unDoCommandStack.push(command);

            }



            .

            .

            .



            else if(input.equalsIgnoreCase("s"))

            {

                System.out.println("Enter ID(enter a to show all): ");

                String input1 = kb.next();



                if(input1.equalsIgnoreCase("a"))

                {

                    for (DVD dvd:dvdStack)

                    {

                        System.out.println(dvd.toString());

                    }

                }



            }

         }

}

I have tried to print out the dvdStack and there are multiple items there. I don't why it doesn't work.

And then, I implemented it by using ArrayList below:

ArrayList<DVD> dvdArrayList = new ArrayList<>();

.

.

.

if(command instanceof CreateDVD)

{

    command.execute();

    dvdArrayList.add( (CreateDVD) command.getDvd() )

    unDoCommandStack.push(command);

}

.

.

.

System.out.println("Enter ID(enter a to show all): ");

String input1 = kb.next();



if(input1.equalsIgnoreCase("a"))

{

    for (DVD dvd:dvdArrayList)

    {

        System.out.println(dvd.toString());

    }

}

This implementation works for displaying all items. However, I have been told to use stack.

Could someone help me to display all items in stack, please?

Every time you enter "c", a new CreateDVD command is created, which has an empty stack.

Then it's executed, which adds a single DVD to its stack.

Then the DVDHandler's stack is replaced by the stack of the CreateDVD command:

dvdStack = ((CreateDVD) command).getDvdStack();

So it's not surprising to only find one DVD in the stack.

Next time, please post more code so we can help with the issue more clearly. However, based on what you have here, a likely solution is using a for loop and the stack.elementAt method. For example:

 public static void stackAttack (int inter){

    Stack<Integer> stack=new Stack<Integer>();

    stack.push(99);

    stack.push(88);

    stack.push(77);

    stack.push(inter);

    for(int n=stack.size(); n>0; n--) {

        System.out.println(stack.elementAt(n-1));

    }

}

public static void main (String args) {

    stackAttack(69);

}

will print out each element of the stack in LIFO order without shrinking it. Hope this helps, and please include more info next time.