Feature request: Allow to provide a "TypeAdapter" for collections [69164099]

Fixed

Bug

Status Update

No update yet.

Description

de...@gmail.com

created issue #1

Nov 10, 2017 06:53PM

Component used: Room
Version used: 1.0
Devices/Android versions reproduced on: NA

I have one entity that contains a set of enums. For example:

@Entity
data class Person(
@field:PrimaryKey val id: Int,
val name: String,
val favouriteDays: Set<Day>)

enum class Day {
MONDAY,
TUESDAY,
WEDNESDAY,
THURSDAY,
FRIDAY,
SATURDAY,
SUNDAY
}

I want to store this entity in a single table. In many cases, especially with enums, we could use a single bit mask to save the list as a number in the database.

Here's one example of what I wanted to do:

object DayCollectionTypeConverter {
@JvmStatic
@TypeConverter
fun daysConverter(days: Set<Day>): Int {
var value = 0
for (day in days) {
value += (1 shl day.ordinal)
}
return value
}

@JvmStatic
@TypeConverter
fun daysConverter(value: Int): Set<Day> {
val set = mutableSetOf<Day>()
for (day in Day.values()) {
if (value and 1 shl day.ordinal != 0) {
set.add(day)
}
}
return set
}
}

That code doesn't work as intended because @TypeConverter would allow me to convert one Day object, but not a collection (or set, list, etc) of Days.

I suggest a new annotation is created so the developer can specify how to save a Collection into a single column in the same table.

Comments

fs...@gmail.com <fs...@gmail.com> #2Nov 11, 2017 12:03AM

hmm it should not ask for a transaction. In fact, we don't want a transaction.
Can you show us that error?

yaraki@, i think we should check if we are already in a transaction before sending vacuum and if so, print a warning and skip vacuum.

yb...@google.com <yb...@google.com> #3Nov 27, 2017 08:24PM

Hello, when I call clearAllTables Room throws an error saying that I should start a Transaction. So I did that, and now the method throws that VACUUM cannot run inside a Transaction.

de...@gmail.com <de...@gmail.com> #4Nov 27, 2017 09:50PM

Can you share the error message saying that a Transaction is needed?

Poc.kt

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yb...@google.com <yb...@google.com> #5Dec 15, 2017 09:39PM

I catch the exception again. As you can see below. but I have see that that error only happen when I run clearAllTables in Main Thread.

I know that we should not do that, and when I run clearAllTables in a background thread it runs without errors.

So I believe that the exception gives a wrong message.

04-02 07:04:06.133 4197-4197/br.com.mobilesales.influxlexical E/AndroidRuntime: FATAL EXCEPTION: main
Process: br.com.mobilesales.influxlexical, PID: 4197
java.lang.IllegalStateException: Cannot perform this operation because there is no current transaction.
at android.database.sqlite.SQLiteSession.throwIfNoTransaction(SQLiteSession.java:915)
at android.database.sqlite.SQLiteSession.endTransaction(SQLiteSession.java:398)
at android.database.sqlite.SQLiteDatabase.endTransaction(SQLiteDatabase.java:524)
at android.arch.persistence.db.framework.FrameworkSQLiteDatabase.endTransaction(FrameworkSQLiteDatabase.java:90)
at android.arch.persistence.room.RoomDatabase.endTransaction(RoomDatabase.java:261)
at br.com.mobilesales.influxlexical.data.source.local.AppDatabase_Impl.clearAllTables(AppDatabase_Impl.java:355)
at br.com.mobilesales.influxlexical.InfluxLexicalApplication$override.logoffUser(InfluxLexicalApplication.java:154)
at br.com.mobilesales.influxlexical.InfluxLexicalApplication$override.access$dispatch(InfluxLexicalApplication.java)
at br.com.mobilesales.influxlexical.InfluxLexicalApplication.logoffUser(InfluxLexicalApplication.java)
at br.com.mobilesales.influxlexical.MainActivity.onOptionsItemSelected(MainActivity.kt:247)
at android.app.Activity.onMenuItemSelected(Activity.java:3204)
at android.support.v4.app.FragmentActivity.onMenuItemSelected(FragmentActivity.java:380)
at android.support.v7.app.AppCompatActivity.onMenuItemSelected(AppCompatActivity.java:195)
at android.support.v7.view.WindowCallbackWrapper.onMenuItemSelected(WindowCallbackWrapper.java:108)
at android.support.v7.view.WindowCallbackWrapper.onMenuItemSelected(WindowCallbackWrapper.java:108)
at android.support.v7.app.ToolbarActionBar$2.onMenuItemClick(ToolbarActionBar.java:63)
at android.support.v7.widget.Toolbar$1.onMenuItemClick(Toolbar.java:203)
at android.support.v7.widget.ActionMenuView$MenuBuilderCallback.onMenuItemSelected(ActionMenuView.java:780)
at android.support.v7.view.menu.MenuBuilder.dispatchMenuItemSelected(MenuBuilder.java:822)
at android.support.v7.view.menu.MenuItemImpl.invoke(MenuItemImpl.java:171)
at android.support.v7.view.menu.MenuBuilder.performItemAction(MenuBuilder.java:973)
at android.support.v7.view.menu.MenuBuilder.performItemAction(MenuBuilder.java:963)
at android.support.v7.widget.ActionMenuView.invokeItem(ActionMenuView.java:624)
at android.support.v7.view.menu.ActionMenuItemView.onClick(ActionMenuItemView.java:150)
at android.view.View.performClick(View.java:5637)
at android.view.View$PerformClick.run(View.java:22429)
at android.os.Handler.handleCallback(Handler.java:751)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:154)
at android.app.ActivityThread.main(ActivityThread.java:6119)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:886)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:776)

yb...@google.com <yb...@google.com> #6Dec 18, 2017 09:29PM

Status: Assigned (reopened)

clearAllTables is not supposed to be run in a main thread. It is annotated with @WorkerThread, and you should always run it in a background thread.

yb...@google.com <yb...@google.com> #7Dec 18, 2017 10:17PM

had a revert the change for a downsteram breakage. working on it.

yb...@google.com <yb...@google.com> Dec 19, 2017 11:43PM

Marked as fixed.