gdlp2004
asked on
Setting a HashMap to a Collection and vice versa
Hi,
I have a HashMap called userSelection that I want to convert to a java Collection and then after it is passed into a new class, I want to change the collection back to a HashMap. I work with collections and hashmaps all the time and have all the imports setup correctly, all I need is a few lines of code as an example to show how to convert these things back and forth.
Thanks in advance!! :)
I have a HashMap called userSelection that I want to convert to a java Collection and then after it is passed into a new class, I want to change the collection back to a HashMap. I work with collections and hashmaps all the time and have all the imports setup correctly, all I need is a few lines of code as an example to show how to convert these things back and forth.
Thanks in advance!! :)
but as a HashMap is a subclass of Collection you can just say:
HashMap hm = new HasMap();
Collection c = hm;
Depends though exactly what it is you need to do.
HashMap hm = new HasMap();
Collection c = hm;
Depends though exactly what it is you need to do.
Yap thats correct just wanna add another comment what objects said with HasMap and Collections are true so the answers
that you need will already be on what objects said.
This tutorial can also add help :
http://java.sun.com/docs/books/tutorial/collections/index.html
http://java.sun.com/docs/books/tutorial/collections/interfaces/index.html
Hope that helps . . .
Javatm
that you need will already be on what objects said.
This tutorial can also add help :
http://java.sun.com/docs/books/tutorial/collections/index.html
http://java.sun.com/docs/books/tutorial/collections/interfaces/index.html
Hope that helps . . .
Javatm
don't forget you will need to cast back to a hashmap
HashMap hm = (HashMap)c;
HashMap hm = (HashMap)c;
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> HashMap is NOT a collection. It is a MAP.
I stand corrected :)
I stand corrected :)
ASKER
Before I test this out, I need to know how to set a HashMap to a collection...is it as easy as everyone originally posted, or is it more complex like MogalManic said?
ASKER
Oh nevermind, I see he did show the two separate ways...I will test them both out right now...
ASKER
Mogal Manic was right on the money...many thanks!
no problem
If you want the keys then use userSelection.keySet()
Or to get the values use userSelection.values()