CODEWITHSUNDEEP
javaarraylistcollectionshashmap
bocante
bocante

Reputation: 9

How to sort a large hashmap on value in a memory efficient way?

I am working on a project and I end up with a large hashmap, and now i am trying to sort it by values.

ArrayList<Map.Entry<String, Integer>> entries = new ArrayList<Map.Entry<String, Integer>>(BloomFilter.map.entrySet());

But when I do this, I get an OutOfMemoryError.

Is there any way to prevent this?

Edit:This my if it's in the bloomfilter function

    hash1 =  MurmurHash2.hash32(genom);
    hash2 =  genom.hashCode();
    inList = true;

    for (int i = 0; i < k-1 ; i++) {

        hashedGenom = ( hash1 + hash2 * i) % a.size();
        hashedGenom = CheckForNegative(hashedGenom);

        if(!(a.get(hashedGenom))){

            a.set(hashedGenom);
            inList = false;
        } 
    }

    return inList;

This is my where im doing bloom filter:

        if(CheckIfThere(s, k, fBitset)){

        //  System.out.println("var");
        val = map.get(s);

        if(val != null){
            map.put(s, map.get(s) + 1);
            //map.remove(s);
            //map.put(s, new Integer(val + 1));
        }else{


            map.put(s,1);

        }

I am basically, getting the string and send it to CheckIfThere and if it gets true i am putting it to hashmap.

Upvotes: 1

Views: 224

Answers (1)

G.Bob
G.Bob

Reputation: 101

there are several algorithm to resolve it

but i think the easiest way is using database.

you can insert all the values into mysql/oracle/sql server/postgres ... and then

select xxxx from xxx order by xxx

if you worried about the database is big and hard to deploy, have a try of sqlite

Upvotes: 1

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