CODEWITHSUNDEEP
java
Rob Mason
Rob Mason

Reputation: 1417

Java Collection, Set, Map or Array to hold unique sorted non blank strings

I am fairly new to java and would like a container that I can use to hold strings that are not empty and have them sorted.

So far, I have mostly been using ArrayList, but this seems a bit limited for this case.

Thanks

Upvotes: 0

Views: 380

Answers (3)

Rob Mason
Rob Mason

Reputation: 1417

Thanks for all the help. Here is what I eventually came up with, using TreeSet and apache commons StringUtils. My Input is a CSV String so, I didn't use the check on the input.

            String csvString = "Cat,Dog, Ball, Hedge,, , Ball, Cat"
            String[] array = StringUtils.split((String) csvString, ",");

            for (int i = 0; i < array.length; i++)
            {
                array[i] = array[i].trim(); //Remove unwanted whitespace
            }

            set = new TreeSet<String>(Arrays.asList(array));
            set.remove("");     //Remove the one empty string if it is there

set now contains: Ball,Cat,Dog,Hedge

Upvotes: 0

succcubbus
succcubbus

Reputation: 894

A Set is what you want, as the items in it have to be unique. As the Strings should be sorted you'll need a TreeSet. As for the non blank Strings you have to override the insertion methods like this:

Set<String> sortedSetOfStrings = new TreeSet<String>() {
    @Override
    public boolean add(String s) {
        if(s.isEmpty())
            return false;

        return super.add(s);
    }
};

EDIT: Simplified thanks to Peter Rader's comment.

Upvotes: 2

Luiggi Mendoza
Luiggi Mendoza

Reputation: 85779

Use TreeSet or TreeMap, depending on your requirements. Both are collections that accept unique elements and keep them sorted.

Upvotes: 2

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