Collection Utils removing duplicates object

Question

I have an Object Person(id, name).

public class Person {


/** Personid. **/
private Long personId;

/** Person Adresse. **/
private String adresse

// Getters, Setters

How can i remove duplicate person (who have same id) using CollectionUtils ? For example Person1(10, aaaa), Person2(10, bbbb), Person3(20, cccc) Result => Person1(10, aaaa), Person3(30, cccc)

EDIT :

This Solution work using Set and overrinding equals and hashcode:

List<Person> oldPerson = new ArrayList<>();
//oldPerson.add ...

Set<Person> newPerson = new HashSet<>(oldPerson);

List<Person> theRightPerson = new ArrayList<>(newPerson);

The solution that i m looking for is something like :

 List<Person> theRightPerson = (List<Person>) CollectionUtils.collect(oldPerson, new Transformer() {

        @Override
        public Object transform(Object input) {
            // TODO Auto-generated method stub
            return null;
        }
    })

@RohitJain You mean with overriding `equals` method with `id` comparison in `Person` class? — Suresh Atta, Feb 24 '14 at 12:44
override the hashCode() and equals() in Person class and use Set to have unique objects. — , Feb 24 '14 at 12:44
I tried it but it doesn't work, it works on a list of elements like List for exemple not List — Anarki, Feb 24 '14 at 12:45
@sᴜʀᴇsʜᴀᴛᴛᴀ Yup. Wanted OP to figure that out :) — Rohit Jain, Feb 24 '14 at 12:45
@RohitJain True :P. I'm little scared with that small statement :) — Suresh Atta, Feb 24 '14 at 12:46
@Avind your idea work, but i saw a way to do this with CollectionUtils and it seems that it's a best way to do this — Anarki, Feb 24 '14 at 12:46
@Anarki May be this ?? http://stackoverflow.com/questions/3559731/java-arraylist-copy-one-to-another-without-duplicates — Suresh Atta, Feb 24 '14 at 12:50
@Zouzou yes and it works, just for information i m looking for a specific solution, look to the last edit — Anarki, Feb 24 '14 at 12:56
@Anarki It works or not? Because you said _"This Solution doesn't work using Set :"_. — Alexis C., Feb 24 '14 at 12:58

score 0 · Answer 1 · edited May 23 '17 at 12:20

0

Overriding equals and hashcode methods and using HashSet would be easier to do. If you can't edit the source of the class, then you need to iterate over the list and compare each item based on criteria.

How to remove duplicate objects in a List<MyObject> without equals/hashcode?

edited May 23 '17 at 12:20

Community

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answered Feb 24 '14 at 15:42

cerberus

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Collection Utils removing duplicates object

1 Answers1