1 /* 2 * Copyright 2018 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 package androidx.work; 18 19 import android.support.annotation.NonNull; 20 import android.support.annotation.RestrictTo; 21 import android.util.Log; 22 23 import java.util.List; 24 25 /** 26 * An abstract class that allows the user to define how to merge a list of inputs to a Worker. 27 */ 28 29 public abstract class InputMerger { 30 31 private static final String TAG = "InputMerger"; 32 33 /** 34 * Merges a list of {@link Data} and outputs a single Data object. 35 * 36 * @param inputs A list of {@link Data} from previous Workers or the WorkRequest.Builder 37 * @return The merged output 38 */ 39 public abstract @NonNull Data merge(@NonNull List<Data> inputs); 40 41 /** 42 * Instantiates an {@link InputMerger} from its class name. 43 * 44 * @param className The name of the {@link InputMerger} class 45 * @return The instantiated {@link InputMerger}, or {@code null} if it could not be instantiated 46 * 47 * @hide 48 */ 49 @RestrictTo(RestrictTo.Scope.LIBRARY_GROUP) 50 @SuppressWarnings("ClassNewInstance") 51 public static InputMerger fromClassName(String className) { 52 try { 53 Class<?> clazz = Class.forName(className); 54 return (InputMerger) clazz.newInstance(); 55 } catch (Exception e) { 56 Log.e(TAG, "Trouble instantiating + " + className, e); 57 } 58 return null; 59 } 60 } 61
