Stuck on assignment (due soon)

[nimm02]

We're making a sort of yahtzee-type dice game.
There are two classes, Die, and Dice. Dice serves as a collection and means of manipulating multiple Die at a time.

The class for the dice is relatively simple and unimportant at the moment storing a 'size' value, a 'value' value, along with set, get, and roll methods.

In the 'Dice' Class, I add desired Die into an ArrayList, as I was told to.
Adding Die to this list is not difficult.

However, I am also to be able to add Die from a and existing 'Dice' object.

Here's what I've got so far.


...
public void add( Die dieToAdd )
{
diceArray.add( dieToAdd );
}
...


This part seems to work fine. (I've already declared the ArrayList a while back.)
Now here is where I get problems.


...
public void add( Dice diceToAdd )
{
Collections.copy(diceToAdd.diceArray,this.diceArray);
}
...


Why this does not work is beyond me. Please help. Much appreciated.

[Norm]

this does not work

Are there error messages? Please copy and paste them here. The text of the message will say what's wrong.

[Xeel]

The question is too generic. Please, post the error message at least. It would be perfect if you attach both of your classes as well tho.

[yulin11]

you'd better put your full source code here. So that we can see the exact problem.




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[_uj]

Why this does not work is beyond me.

And what doesn't work is beyond everybody else.

Maybe the problem is that Collections.copy doesn't make a deep copy, only a shallow one. This means that no actual copies of the Dice objects are created when they're copied to the new ArrayList. Only the references to the objects are copied, not the objects themselves. After the copy you have two ArrayLists referencing the same objects.