User Mention

Once you have mentioned someone, they receive a notification that you have quoted them (except in a private message). You can mention several people in a message.

Example: Here how to mention someone with [[user:ID]] into a news feed post

Long franckId = 1234567890L;
String message = "Hey [[user:" + franckId + "]] what's up today?";

FeedPost feedPost = new FeedPost.Builder()
  .setMessage(message)
  .setVisibility(AccessControl.PUBLIC)
  .build();

Feed createdFeed = session.getNewsFeed().blockingCreate(feedPost);
List<UserMentionTag> userMentionTags = createdFeed.getBodyMessageTagEntities().getUserMentionTags();

for (UserMentionTag userMentionTag : userMentionTags) {
  System.out.println(userMentionTag.getMentionedUser().getDisplayedName() + "has been mentioned");
}
let franckId = 1234567890
let message = "Hey [[user:\(franckId)]] what's up today?"

let feedPost = try FeedPost.Builder()
  .setMessage(message)
  .setVisibility(.Public)
    .build()
                
let createdFeed = try session.newsFeed.blockingCreate(feedPost)
let userMentionTags = createdFeed?.bodyMessageTagEntities?.userMentionTags

userMentionTags?.forEach {
    NSLog("\($0.mentionedUser!.displayedName!) has been mentioned")
}
let post = (new FeedPost())
    .setMessage("Hey [[user:\("+user.id+")]] what's up today?")
    .setVisibility(AccessControl.Public);
let feed = await session.newsFeed.create(post);
let post = (new FeedPost())
    .setMessage("Hey [[user:\("+user.id+")]] what's up today?")
    .setVisibility(AccessControl.Public);
session.newsFeed.create(post).then((feed) => {

});

user_mention_tag JSON object looks like this

{
  "id": 15447969996360896,
  "created_date": "2018-07-30T12:09:59Z",
  "mentioned_user": {
    "id": 7346619847208778000,
    "entity_type": "USER",
    "id_str": "7346619847208777471",
    "type": "User"
  },
  "start_index": 4,
  "end_index": 20,
  "access_control": "PUBLIC",
  "entity_type": "USER_MENTION_TAG",
  "id_str": "15447969996360897",
  "type": "UserMentionTag"
}