| /* |
| * Copyright 2019 The Android Open Source Project |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| package androidx.work |
| |
| import android.content.Context |
| import java.util.concurrent.CopyOnWriteArrayList |
| |
| /** |
| * A [WorkerFactory] which delegates to other factories. Factories can register themselves |
| * as delegates, and they will be invoked in order until a delegated factory returns a |
| * non-null [ListenableWorker] instance. |
| */ |
| open class DelegatingWorkerFactory : WorkerFactory() { |
| // Use a CopyOnWriteArrayList here to allow modifying a list of factories during |
| // iteration. This allows createWorker() to call addFactory(). |
| private val factories: MutableList<WorkerFactory> = CopyOnWriteArrayList() |
| |
| /** |
| * Adds a [WorkerFactory] to the list of delegates. |
| * |
| * @param workerFactory The [WorkerFactory] instance. |
| */ |
| fun addFactory(workerFactory: WorkerFactory) { |
| factories.add(workerFactory) |
| } |
| |
| final override fun createWorker( |
| appContext: Context, |
| workerClassName: String, |
| workerParameters: WorkerParameters |
| ): ListenableWorker? { |
| // If none of the delegates can instantiate a ListenableWorker return null |
| // so we can fallback to the default factory which is based on reflection. |
| return factories.firstNotNullOfOrNull { factory -> |
| try { |
| factory.createWorker(appContext, workerClassName, workerParameters) |
| } catch (throwable: Throwable) { |
| val message = "Unable to instantiate a ListenableWorker ($workerClassName)" |
| Logger.get().error(TAG, message, throwable) |
| throw throwable |
| } |
| } |
| } |
| } |
| |
| private val TAG = Logger.tagWithPrefix("DelegatingWkrFctry") |
