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private val scope = CoroutineScope(taskThreading.ui() + SupervisorJob())  

fun processStateCollection() {
  stateFlow
    .filter {
      stateFlow -> stateFlow != null
    }.onEach { stateFlow ->
      tweetsListUI?.handleStates(stateFlow)
    }.launchIn(scope)
}

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@ActivityScope
class StateFlowHandler @Inject constructor(taskThreading: TaskThreading) {

  private var tweetsListUI: TweetsListUI? = null

  private lateinit var stateFlow: StateFlow<TweetsUIState?>

  fun init(val stateFlow: StateFlow<TweetsUIState?>, val tweetsListUI: TweetsListUI) {
    stateFlow = stateFlow
    tweetsListUI = tweetsListUI

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public class TweetsListUI extends ViewUI  {
  @Inject
  SearchViewDelegate viewDelegate;

  @Inject
  StateFlowHandler stateFlowHandler;

  public void initStateFlow(@NotNull StateFlow<? extends TweetsUIState> stateFlow) {
    stateFlowHandler.init(stateFlow, this);
    stateFlowHandler.processStateFlowCollection();

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@ActivityScope
class SearchViewDelegate @Inject constructor(
  private val presenter: SearchTweetPresenter,
  private val taskThreading: TaskThreading
) {
  
  private fun getStateFlow(): StateFlow<TweetsUIState> = presenter.stateFlow

  @FlowPreview
  @ExperimentalCoroutinesApi

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@ActivityScope
public class SearchTweetPresenter {
// ...

public void searchTweets(@NotNull final String query) {
  // TODO Remove callback code:
  // if (callback == null && view != null) {
  //  callback = new SearchCallbackImpl(view);
  // }
  tweetSearchUseCase.execute(query);

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@ActivityScope
public class SearchTweetPresenter {
  @NotNull
  private final SearchTweetUseCase tweetSearchUseCase;

  @Inject
  public SearchTweetPresenter(@NotNull SearchTweetUseCase tweetSearchUseCase) {
    this.tweetSearchUseCase = tweetSearchUseCase;
  }

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override fun execute(query: String) {
  tweetsStateFlow.value = TweetsUIState.LoadingUIState
  
  repository.searchTweet(query)
    .onEach { tweets ->
      val stateFlow =
      if (tweets.isEmpty()) {
        TweetsUIState.EmptyUIState
      } else {
        TweetsUIState.ListResultsUIState(tweets)

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override fun execute(query: String) {
  // TODO remove this: callback?.onShowLoader()
  // add new Loading state
  tweetsStateFlow.value = TweetsUIState.LoadingUIState

  // ...
}

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// Use Case contract with Callback input parameter
interface UseCase<T> {
   fun execute(param: String, callbackInput: T?)

   fun cancel()
}

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/**
* UI States defined for StateFlow in the workflow
*/
sealed class TweetsUIState {
  // List of results coming from the Data layer
  data class ListResultsUIState(val tweets: List<Tweet>): TweetsUIState()
  // Error state with error message
  data class ErrorUIState(val msg: String): TweetsUIState()
  // Empty state with "no results" String
  object EmptyUIState: TweetsUIState()