asked on 5/21/2012

java extract key from map and creating sorted set

Hi experts,

I am a novice in Java and I would like to extract the values of a map and add them into a sorted set.

Map<String, List<String>> xxx

Thanks

Duke001

Java Programming

Last Comment

CEHJ

5/22/2012

CEHJ

5/21/2012

Try

SortedSet<List<String>> set = new TreeSet<List<String>>(xxx.values());

Open in new window

Duke001

5/21/2012

ASKER

i get the following error message:
Semantic error: java.util.ArrayList cannot be cast to java.lang.Comparable

CEHJ

5/21/2012

OK. How are you envisaging the sort is meant to work?

Duke001

5/21/2012

ASKER

I would like to create a set in alphabetical order, without duplication.
Thanks

CEHJ

5/21/2012

But your values are already Lists of Strings ...

Duke001

5/21/2012

ASKER

Please find attached the method used to populate the List<String> value of the map.
thanks

CEHJ

5/21/2012

Nothing attached...

Duke001

5/21/2012

ASKER

very strange ... but please have a look now.
method.txt

CEHJ

5/21/2012

You need to post the real code - that would neither work nor even compile

Duke001

5/22/2012

ASKER

please find attached all methods.
Problem2.txt

CEHJ

5/22/2012

OK. I suspect you're not quite asking for the right thing. You can't really have a SortedSet of Lists of Strings, since they wouldn't really be orderable. If you think otherwise, please tell me how they are to be ordered.

Are you sure you don't just want to eliminate duplicates from something you've got already?

Duke001

5/22/2012

ASKER

This is waht the question says:

"Write a public instance method for EmergencyManager called
allDrivers(), with no argument, that, based on the data available in
qualifiedDrivers, extracts, assembles and returns a collection of a
suitable type that itemizes all of the volunteer drivers in alphabetical
order, without duplication. Note that this method does not need to used
by any other method of EmergencyManager."

Thanks

ASKER CERTIFIED SOLUTION

CEHJ

5/22/2012

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Duke001

5/22/2012

ASKER

error: "cannot find symbol - variable whoDrivesWhat

Duke001

5/22/2012

ASKER

Sorry, but having read the question:

"based on the data available in qualifiedDrivers" ... am wrong to say that the information must be retrieved from the map and not from the whoDrivesWhat?

Thanks

Duke001

5/22/2012

ASKER

I have compiled the code with the "String[][] whoDrivesWhat" content in it and it works but I think that is against the assumption of the question.

Thanks

CEHJ

5/22/2012

Well i'm not sure of that. It will certainly give you 'all of the volunteer drivers in alphabetical
order, without duplication'. If that is not what's required, then the method name 'allDrivers' is a bad one

Duke001

5/22/2012

ASKER

Ok, I am going to accept your suggestion and let see what happens.
Thanks for your support.

Duke001

CEHJ

5/22/2012