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Retrieval Order of Iterator Interface
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Rajendra Prakash
Ranch Hand
Joined: Sep 10, 2009
Posts: 293
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what is the retrieval order of Iterator. I mean iterator iterates Inserted order or reverse order.
If i want to change the order means, what i have to do
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Jesper de Jong
Java Cowboy
Bartender
Joined: Aug 16, 2005
Posts: 12907
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That depends entirely on the collection you're iterating over. Some collections have a defined order (for example a List), some are not ordered (for example a HashSet), so the order of iteration is undefined.
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Rob Spoor
Sheriff
Joined: Oct 27, 2005
Posts: 19216
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Note that undefined does not mean random. The order will most likely be the same if you're iterating twice in a row without modifying the collection.
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Jesper de Jong
Java Cowboy
Bartender
Joined: Aug 16, 2005
Posts: 12907
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Rob Prime wrote:The order will most likely be the same if you're iterating twice in a row without modifying the collection.
Yes, but there's no guarantee that that's always so, so don't write your program to rely on that fact.
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Lalit Mehra
Ranch Hand
Joined: Jun 08, 2010
Posts: 369
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There always is some order an Iterator iterates on ...
the only thing is that sometimes its known as in case of a linked list ... and sometimes it's not as in case of a hashmap ...
as haspmaps store elements using hashing while in a linked list the iteration is simple ... using the links only ..
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subject: Retrieval Order of Iterator Interface
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