asked on

Continuing Advice requested

reference: https://www.experts-exchange.com/questions/21153763/Looking-for-advice.html

for each method similar to insert in the mySequence class, you said i need to return a Position instance, which makes sense...but what exactly is the instance's value each time? what am I returning? and where do i grab this from?? I am quite a noob to java...but i'm sure you already figured that. sry for the questions!!! thanks so much.

Mick Barry

you'll return a new instance of your myPosition class that wraps the relevent element.

ie. the elements() method of the created instance will return the appropriate Comparable instance.

D4Ly

ASKER

can you give me a for example for my insert()?

public Position insert(Comparable o) {
_seq.insert(o);
return null;
}

ASKER CERTIFIED SOLUTION

Mick Barry

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D4Ly

ASKER

thx again. you the man.

D4Ly

ASKER

what exactly does Positions do for me?

Mick Barry

the Position class defines the methods required by any class that implements it.
See the link I posted in your previous question for a more details explanation of interfaces (than I can give you).

also here:
http://java.sun.com/docs/books/tutorial/java/interpack/interfaces.html

D4Ly

ASKER

nono, i understand what an interface does...i am just wondering how the application of using datatype Positions impacts my problem. make sense?

Mick Barry

not sure i follow, what problem are you referring to?

D4Ly

ASKER

My problem, being the entire task i am trying to accomplish, creating a positional container out of an arrayList. I am unsure why myPositions and Positions classes are needed in order to accomplish this. I'm just not understanding the point of needing type Position conceptually.
=============================================
Can you help with this one?

public Comparable remove(Position p) {
_seq.remove(p);
return new myPosition(p);
}

this should be my last issue with this problem. Here's what I know. Position p is the slot in the arrayList containing the data I want to remove. My remove method is expecting an int, not a Position.

Do I typecast p to an int value? Is there a different way to approach this? I know I can't call _arr[p] to access my _arr array's value at p when p is of type Position. I also know that typcasting from type Position to type Integer to type Int does not work, or at least i can't figure out how to. So, after I've figured out how to remove the value from the array in position p, I want to return the value of _arr[p], and i know my remove() method returns type Object. But how do I return type Object as type Position? Thanks again

D4Ly

ASKER

I'll put it in a new q for pts.

Mick Barry

> I am unsure why myPositions and Positions classes are needed in order to accomplish this.

I'm not sure either actually as I hinted on earlier. The Position just seems to be a thin wrapper around the Comparable instance.
Perhaps ask your lecturer.