stream list into a set

Question

I am looking to refactor how I have used a stream in some of my code. The first example is how I currently have done it. The second example is what im trying to make it look like.

Set<String> results = new HashSet<String>();

someDao.findByType(type)
            .stream()
            .forEach(t-> result.add(t.getSomeMethodValue()) );

Could it look something like this? If so how do I make it do it?

Set<String> results = someDao.findByType(type)
            .stream()
            .collect(  /*  ?? no sure what to put here  */ );

Solution

Use Collectors.toSet :

Set<String> results = someDao.findByType(type)
        .stream()
        .map(ClassName::getValue)
        .collect(Collectors.toSet());

Comments

[Alexis C.]

You need to map the Stream elements before collecting them into the Set. someDao.findByType(type) .stream().map(TheClass::getValue).collect(toSet());