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Colloection choice, which one is best for my problem

ajackson99
ajackson99 asked
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Last Modified: 2012-05-05
I have been studing the collection material I could find on the webulator, My problem is as follows;

1, Class a (customers) containd a Cust_ID String and a customer name.
2, Class b (SalesOrder) contains details of sales orders including Cust_ID which has a one to many relationship with class a

I would like to create a data structure which contains both sets of data with class a as the key and class b as the
value(s).

I would like to be able to retrieve multiple instances of class b dependant on a value of class a.  I also want that class b is retrieved in a particular sequence (Document number)

I have looked at MAPs   but they want unique values.

I do not want anyone to write the code ,just a nudge in the right direction, I'm thinking TreeSets. Examples of code pertaining to nudging however will not be frowned upon.
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CERTIFIED EXPERT
Top Expert 2016

Commented:
You need

Map<ClassA, List<ClassB>>;
Top Expert 2006

Commented:
> I also want that class b is retrieved in a particular sequence (Document number)
Use TreeSet or PriorityQueue for bs
Java Developer
CERTIFIED EXPERT
Top Expert 2010
Commented:
i'd go with:

Map<A, TreeSet<B>>;

make B implement Comparable ordering by doc number

http://java.sun.com/docs/books/tutorial/collections/index.html
http://javaalmanac.com/egs/java.util/coll_SortSet.html

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