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Comparing Object Elements  RSS feed

 
Mike Stevens
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Hi again all, I was wondering if some one could help me.

What I'm tring to do is compare elements in an ArrayList. I must use the method signature and the ArrayList stock.add(item) but the rest of the body I can change (as long as it is not to advanced yet).



Any help on pointing me in the right direction on how to compare these different object id's would be great

Thanks
Mike
 
David McCombs
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What errors is the compiler giving?

Does getID() really exist(check spelling) in that class and what is its visibility modifiers?

The easiest way to do this is check to see if Product implements Comparable and the compareTo() method does what you need. If it doesn't, and you can change Product, do it this way.
 
Mike Stevens
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Hi David the error I get is can't find symbol - method getId() but only when I try to call the local var stockString.getID(). If I take this out there is no error but I can not compare either

I'm not sure what you mean by this

The easiest way to do this is check to see if Product implements Comparable and the compareTo() method does what you need. If it doesn't, and you can change Product, do it this way.

I'm using the class Product method getID() in a number of other methods and all works fine along with some other Product methods.

I think I cannot use the Product method getID() on the local var I'm just not really sure how else to compare it.
 
David Nemeskey
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Mike,

please have a good look at your code! You are calling the method of the object. I suspect you wanted to write , didn't you?

Regards,
David
 
sven studde
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Does getID() really exist(check spelling) in that class and what is its visibility modifiers?

Check the ArrayList class in the java docs and see for yourself.


Don't declare variables inside loops. Otherwise, they get redeclared everytime through the loop. Instead, declare them outside the loop, and then make assignments to them inside the loop.
[ November 10, 2006: Message edited by: sven studde ]
 
David Nemeskey
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Sven:

is that really so? I thought the compiler was smarter than that.
 
Mike Stevens
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Originally posted by David Nemeskey:
Mike,

please have a good look at your code! You are calling the method of the object. I suspect you wanted to write , didn't you?

Regards,
David


I tried this last night and it compiled, it just never added it to the collection

with
stock.add(item);

I'm going to have a fresh look at my method and these posts later today
 
Mike Stevens
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Originally posted by Mike Stevens:


I tried this last night and it compiled, it just never added it to the collection

with

I'm going to have a fresh look at my method and these posts later today
PS Thanks for taking a boo
 
Tim LeMaster
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This seems completely unneeded.
 
Mike Stevens
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Originally posted by Tim LeMaster:


This seems completely unneeded.


It is I was just trying to pass

item
in to
stockString
to see if this would make a difference

It is commented out now

Thanks for taking a look
Mike
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