/*
* Copyright 2018 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
/**
* An abstract class that allows the user to define how to merge a list of inputs to a
* [ListenableWorker].
*
* Before workers run, they receive input [Data] from their parent workers, as well as
* anything specified directly to them via [WorkRequest.Builder.setInputData]. An
* InputMerger takes all of these objects and converts them to a single merged [Data] to be
* used as the worker input. [WorkManager] offers two concrete InputMerger implementations:
* [OverwritingInputMerger] and [ArrayCreatingInputMerger].
*
* Note that the list of inputs to merge is in an unspecified order. You should not make
* assumptions about the order of inputs.
*/
abstract class InputMerger {
/**
* Merges a list of [Data] and outputs a single Data object.
*
* @param inputs A list of [Data]
* @return The merged output
*/
abstract fun merge(inputs: List<Data>): Data
}
private val TAG = Logger.tagWithPrefix("InputMerger")
internal fun fromClassName(className: String): InputMerger? {
try {
val clazz = Class.forName(className)
return clazz.getDeclaredConstructor().newInstance() as InputMerger
} catch (e: Exception) {
Logger.get().error(TAG, "Trouble instantiating $className", e)
}
return null
}