Bubble Sort objects

[dougie1809]

Hi,

I am trying to sort out a Stack of Dvd objects, I have a Dvd class which implements Comparator<Dvd>. The following code snippet below is the method that overrides the compare() method:

public int compare(Dvd dvd1, Dvd dvd2)
	{
		return dvd1.getTitle().compareTo(dvd2.getTitle());
	}

In another class I have a main method which tests this statement which I am also trying to implement it into a bubble sort method:

for(int x=1;x<10;x++)
		{
			for(int y=0;y<10-x;y++)
			{
				if(Dvd.compare(dvds(y), dvds(y+1))>0)
				{
				}
			}
		}

Im not going to go any further with the sorting code until I have the if statement correct, which I have called the overrided compare method in Dvd to compare two objects which is running in two for loops to compare all Dvds in the Stack dvds. ?
Thanks

[Norm]

Does the dvds() method return a Dvd object from some collection?

Add some println statements to the code to print out the values being compared and the value returned by the compare statement to see if the code is doing what you want.

The compare() method (Dvd.compare) is coded like it was a static method: Classname.methodname()

[dougie1809]

Sorry I never mentioned that the if statement compiles. It doesn't. I dont have a dvds() method. The dvds is a Stack of dvd object, where I am trying to compare dvd elements in dvds by indexing them? This obviously a mistake.
Thanks

[Norm]

With a Stack you can only look at the top element. What is underneath is hidden.
If you want to sort the objects, put them into another type of container. Why use a Stack?

[dougie1809]

Yes I understand that, but can you not put stack elements into a collection, and then compare the elements that way? And then use the comparing method on the bubble sort?
I chose Stack because it the data structure I am dealing with for a project.
Thanks

[Norm]

Why do you want a Stack?
Yes you could take the elements out of the Stack and put them into a collection.

[dougie1809]

Well I never knew I'd come into problems like these I guess, but I'm far into trying to accomplish this, rather than to pick a different data structure.
What would be the better option would you recommend; Taking the elements from the Stack into a collection, or into String array of elements? In terms of comparing elements?
Thanks

[Norm]

Why are you using a Stack?

[dougie1809]

Because I am doing an analysis on data structures, So i have chosen a Stack.

[Norm]

Many data structures are for a specific purpose. Have you chosen one suitable for your purpose?

It sounds like you are trying to put a square peg into a round hole.

[dougie1809]

Yes, I am creating a logical DVD rack so I can push DVD's and pop them off the stack on top. And then I am trying to be able to sort the elements which have being pushed onto the stack. I am not actually accessing any data within the stack, only trying to sort the data.
Thanks

[Norm]

Then the order that the items were put in the stack is not important.

[dougie1809]

Its not important in the real sense, but in the project for my analysis is important. All I am asking is what would be the recommended way of storing the stack elements into; An array or a Collection?

As you did say that you cannot sort elements in a Stack by itself?
Thanks

[Norm]

Look at the API doc for the Stack class and see if it or the class it extends has any methods that you could use.

[dougie1809]

Don't worry, I tried looking not only just the API, but over the net. But thanks for your time and effort.

[Norm]

I don't think you have looked at what I suggested. What class does Stack extend?

[dougie1809]

Stack extends Vector which has 3 methods.

[Norm]

Try counting again. There are lots more than 3 methods in the Vector class.

[dougie1809]

My bad, I was looking at a complete different section of the page. Anyway, yes I see there are alot of methods, but is there a method that I can compare one object to the other?

[Norm]

there a method that I can compare one object to the other?

Did any of them look likely to do that?