diff options
Diffstat (limited to 'taler-kotlin-common/src/main/java/net/taler/common/Event.kt')
-rw-r--r-- | taler-kotlin-common/src/main/java/net/taler/common/Event.kt | 51 |
1 files changed, 0 insertions, 51 deletions
diff --git a/taler-kotlin-common/src/main/java/net/taler/common/Event.kt b/taler-kotlin-common/src/main/java/net/taler/common/Event.kt deleted file mode 100644 index 779247f..0000000 --- a/taler-kotlin-common/src/main/java/net/taler/common/Event.kt +++ /dev/null @@ -1,51 +0,0 @@ -/* - * This file is part of GNU Taler - * (C) 2020 Taler Systems S.A. - * - * GNU Taler is free software; you can redistribute it and/or modify it under the - * terms of the GNU General Public License as published by the Free Software - * Foundation; either version 3, or (at your option) any later version. - * - * GNU Taler is distributed in the hope that it will be useful, but WITHOUT ANY - * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR - * A PARTICULAR PURPOSE. See the GNU General Public License for more details. - * - * You should have received a copy of the GNU General Public License along with - * GNU Taler; see the file COPYING. If not, see <http://www.gnu.org/licenses/> - */ - -package net.taler.common - -import androidx.lifecycle.LiveData -import androidx.lifecycle.Observer -import java.util.concurrent.atomic.AtomicBoolean - -/** - * Used as a wrapper for data that is exposed via a [LiveData] that represents an one-time event. - */ -open class Event<out T>(private val content: T) { - - private val isConsumed = AtomicBoolean(false) - - /** - * Returns the content and prevents its use again. - */ - fun getIfNotConsumed(): T? { - return if (isConsumed.compareAndSet(false, true)) content else null - } - -} - -fun <T> T.toEvent() = Event(this) - -/** - * An [Observer] for [Event]s, simplifying the pattern of checking if the [Event]'s content has - * already been consumed. - * - * [onEvent] is *only* called if the [Event]'s contents has not been consumed. - */ -class EventObserver<T>(private val onEvent: (T) -> Unit) : Observer<Event<T>> { - override fun onChanged(event: Event<T>?) { - event?.getIfNotConsumed()?.let { onEvent(it) } - } -} |