Provide Flow based APIs for InvalidationTracker [252899305]

Fixed

Feature Request

Status Update

No update yet.

Description

da...@google.com

created issue #1

Oct 11, 2022 01:14AM

The use-case is to 'drive' a Flow stream off invalidations from Room.

For example, say you have TableOne and TableTwo and you want to combine data from both, querying in a transaction and avoiding intermediate emissions since an operation write both tables in a transaction. Then one could use such API to drive the stream, like this:

suspend fun getCombinedData(): Flow<CombinedData> {
  // Create an observer of the tables that would invalidate the flow
  return db.invalidationTracker.createObserverFlow(arrayOf("TableOne", "TableTwo")).map { _ ->
    val (dataFromTableOne, dataFromTableTwo) = db.withTransaction {
      dao.getDataOneSuspending() to dao.getDataTwoSuspending()
    }
    combineTransform(dataFromTableOne, dataFromTableTwo) // returns List<CombinedData>
  )
}

Comments

ap...@google.com <ap...@google.com> #2Oct 21, 2022 03:18PM

Project: platform/frameworks/support
Branch: androidx-main

commit 0e8a872f86335da978d3f21a536cb82340578f4d
Author: Daniel Santiago Rivera <danysantiago@google.com>
Date: Tue Oct 11 12:44:58 2022

Provide an API for creating a Flow that emits invalidation tracker changes.

This API servers as a bridge between Room's InvalidationTracker Observer APIs and coroutines Flow.

Bug: 252899305
Test: InvalidationTrackerFlowTest
Relnote: Add an API for creating a Flow that emits invalidation tracker changes. The API is useful for creating streams that need to react to database changes.
Change-Id: I8c7904f0d630bfc48574af96e288e8c7b5bf777a

M room/integration-tests/kotlintestapp/src/androidTest/java/androidx/room/integration/kotlintestapp/dao/BooksDao.kt
A room/integration-tests/kotlintestapp/src/androidTest/java/androidx/room/integration/kotlintestapp/test/InvalidationTrackerFlowTest.kt
M room/room-ktx/api/current.txt
M room/room-ktx/api/public_plus_experimental_current.txt
M room/room-ktx/api/restricted_current.txt
M room/room-ktx/src/main/java/androidx/room/RoomDatabaseExt.kt

https://android-review.googlesource.com/2249913

da...@google.com <da...@google.com> Apr 26, 2023 07:28PM

Marked as fixed, reassigned to da...@google.com.

Issue 252899305

Description

Issue summary

Comments

ap...@google.com <ap...@google.com> #2Oct 21, 2022 03:18PM

da...@google.com <da...@google.com> Apr 26, 2023 07:28PM

Add comment

Issue metadata