CODEWITHSUNDEEP
javaarraylist
Crypt Junior
Crypt Junior

Reputation: 331

Grabbing an existing ArrayList and adding values onto it from a getter

So I'm wondering how would I be able to grab the currents values from an ArrayList and add-on values to it.

 private List<String> friends;

public Profile(List<String> friends){
  this.friends = friends
 }

public List<String> getFriends() {
    return friends;
}

public void addFriend(List<String> friends) {
   this.friends = getFriends() + friends;
}

Obviously, the method "addFriend" won't working because an operator cannot be applied to an ArrayList. It supposes to be an example of how it should exactly work. Grabbing getFriends() method and applying another list to it. So is there a way that I can accomplish this task? Grabbing a getter ArrayList and adding values ONTO it.

Note: Already assumed that the data is stored somewhere in an hashmap with a key and a value as an List

Upvotes: 0

Views: 86

Answers (5)

Crypt Junior
Crypt Junior

Reputation: 331

All of these answers will work, I might as well add a my own solution as well.

public void addFriend(List<String> friends) {
     this.friends.addAll(friends.stream().collect(Collectors.toList()));
}

Upvotes: 0

Luis Gonz&#225;lez
Luis Gonz&#225;lez

Reputation: 3559

You could create two different methods:

This way you add a list of friends to the current list

public void addFriend(List<String> friends) {
   this.friends.addAll(friends);
}

This way you only add one friend

public void addFriend(String friend) {
   this.friends.add(friend);
}

With this approach you will have two different behaviours for adding friends.

Upvotes: 0

Nir Levy
Nir Levy

Reputation: 12953

You can use ArrayList.addAll(Collection c) method:

public void addFriend(List<String> friends) {
   this.friends.addAll(friends);
}

Upvotes: 0

Mohammed Aouf Zouag
Mohammed Aouf Zouag

Reputation: 17142

You can use this:

public void addFriend(List<String> friends) {
   this.friends.addAll(friends);
}

Upvotes: 1

Zizouz212
Zizouz212

Reputation: 4998

Why don't you just iterate and add to the friends field? It's already a list...

public void addFriend(List<String> friends) {
    for (String friend : friends) {
        this.friends.add(friend);
    }
}

Upvotes: 1

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