Creating objects with parameters in Java 8 Stream

Question

Is it possible to create objects with parameters while using Stream class? I'd like to reproduce the following with Java 8 Stream.

for(Integer id:someCollectionContainingTheIntegers){
     someClass.getList().add(new Whatever(param1, id));
}

janos · Accepted Answer · 2017-05-14 13:38:40Z

6

Sure. But if you have a collection, you can use forEach and a lambda:

someCollectionContainingTheIntegers.forEach(id -> someClass.getList().add(new Whatever(param1, id));

Another possible variation is to collect into the destination list:

someCollectionContainingTheIntegers.stream()
    .map(id -> new Whatever(param1, id))
    .collect(Collectors.toCollection(() -> someClass.getList()));

edited May 14, 2017 at 13:38

answered May 14, 2017 at 13:15

janos

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1 Comment

Max Beaver Over a year ago

Thank you very much, Janos :)

Bor Laze · Accepted Answer · 2017-05-14 13:23:40Z

2

One more solution...

    List<Whatever> collect = someCollectionContainingTheIntegers.stream()
            .map(id -> new Whatever(param1, id))
            .collect(toList());
    someClass.getList().addAll(collect);

answered May 14, 2017 at 13:23

Bor Laze

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Comments

ΦXocę 웃 Пepeúpa ツ · Accepted Answer · 2017-05-14 13:17:48Z

1

do a foreach in the list

List<Integer> ml = new ArrayList<>(Arrays.asList(1, 2, 3, 4));
List<Integer> ml2 = Arrays.asList(21, 22, 23, 24);
ml2.forEach(x -> ml.add(x));
System.out.println(ml);

answered May 14, 2017 at 13:17

ΦXocę 웃 Пepeúpa ツ

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