org.springframework.messaging.simp.user

## Interface SimpUserRegistry

- All Known Implementing Classes:
    DefaultSimpUserRegistry, MultiServerUserRegistry

      public interface SimpUserRegistry

  A registry of currently connected users.
  Since:
    4.2
  Author:
    Rossen Stoyanchev

- - ### Method Summary

    All Methods Instance Methods Abstract Methods
    Modifier and Type | Method and Description
    --- | ---
    `Set<SimpSubscription>` | `findSubscriptions(SimpSubscriptionMatcher matcher)` Find subscriptions with the given matcher.
    `SimpUser` | `getUser(String userName)` Get the user for the given name.
    `int` | `getUserCount()` Return the count of all connected users.
    `Set<SimpUser>` | `getUsers()` Return a snapshot of all connected users.

- - ### Method Detail

    - #### getUser

          @Nullable
          SimpUser getUser(String userName)

      Get the user for the given name.
      Parameters:
        `userName` - the name of the user to look up
      Returns:
        the user, or `null` if not connected

    - #### getUsers

          Set<SimpUser> getUsers()

      Return a snapshot of all connected users.

      The returned set is a copy and will not reflect further changes.

      Returns:
        the connected users, or an empty set if none

    - #### getUserCount

          int getUserCount()

      Return the count of all connected users.
      Returns:
        the number of connected users
      Since:
        4.3.5

    - #### findSubscriptions

          Set<SimpSubscription> findSubscriptions(SimpSubscriptionMatcher matcher)

      Find subscriptions with the given matcher.
      Parameters:
        `matcher` - the matcher to use
      Returns:
        a set of matching subscriptions, or an empty set if none