How to use Hashset for non-string objects in java

Question

Lets say I have created a class called Time whose constructor takes 3 params. hour, mins and secs. Now, I create an object t1 = new Time(10, 10, 10); and then another object t2 = new Time(10, 10, 10)

now I use them in hashset.

hashset.add(t1);
hashset.add(t2);

Now size of hashset would be 2. How to modify this to be of size 1 if the values of the objects is the same ?

example:

void eradicateDuplicate(List<Time> list) {

  for (Time t : list) {
     hashSet.add(t);
   } 

}

I want this code to eradicate all duplicate time objects with the same value ?

Thanks,

score 5 · Accepted Answer · edited Aug 05 '13 at 05:43

5

This will happen automatically IF you implement the methods #hashCode and #equals in your Time object.

edited Aug 05 '13 at 05:43

Philippe Marschall

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answered Aug 04 '13 at 23:41

MTilsted

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1

And [implement it well](http://stackoverflow.com/questions/27581/overriding-equals-and-hashcode-in-java) – Steven Schlansker Aug 05 '13 at 05:59

score 0 · Answer 2 · answered Aug 04 '13 at 23:38

0

You don't need to do anything. The second will not be added if it is the same as the first.

answered Aug 04 '13 at 23:38

tbodt

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How to use Hashset for non-string objects in java

2 Answers2