Question

I am having some problem with java hashtable. Following is my hastable key and values

{corpus\2.txt=[cat sparrow], corpus\4.txt=[elephant sparrow], corpus\1.txt=[elephant cow], corpus\3.txt=[cow cat]}

So if i want to access first tuple i have to pass key “corpus\2.txt” to get its value. If i pass value i can get it’s key. But I want to make a function I pass like 1 2 3 4 etc. and get both key and value. Any idea?

2nd question:
Is it possible to store an index with key and value too?? Or is it possible to get index ( 0,1,2,3 etc. ) from existing hashtable?

Thanks !

Answer 1

For starters, I would use a HashMap, rather than the (now obsolete) HashTable. If you do that, then you can use Map.Entry to return a key/value pair (as per your first question).

You can’t easily store an index with your key. You might want to create a special Key object thus:

public class Key {
   private String name;
   private int index;
   ....
}

with a suitable equals()/hashCode() implementation (as pointed out below in the comments) and use that as the key in your HashMap. You’ve have to perform a lookup using this key and thus construct one from your current String-based key, but I don’t think that’s a big deal.