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 17package androidx.paging; 18 19import androidx.annotation.NonNull; 20import androidx.arch.core.util.Function; 21 22import java.util.List; 23 24class WrapperPositionalDataSource<A, B> extends PositionalDataSource<B> { 25 private final PositionalDataSource<A> mSource; 26 private final Function<List<A>, List<B>> mListFunction; 27 28 WrapperPositionalDataSource(PositionalDataSource<A> source, 29 Function<List<A>, List<B>> listFunction) { 30 mSource = source; 31 mListFunction = listFunction; 32 } 33 34 @Override 35 public void addInvalidatedCallback(@NonNull InvalidatedCallback onInvalidatedCallback) { 36 mSource.addInvalidatedCallback(onInvalidatedCallback); 37 } 38 39 @Override 40 public void removeInvalidatedCallback(@NonNull InvalidatedCallback onInvalidatedCallback) { 41 mSource.removeInvalidatedCallback(onInvalidatedCallback); 42 } 43 44 @Override 45 public void invalidate() { 46 mSource.invalidate(); 47 } 48 49 @Override 50 public boolean isInvalid() { 51 return mSource.isInvalid(); 52 } 53 54 @Override 55 public void loadInitial(@NonNull LoadInitialParams params, 56 final @NonNull LoadInitialCallback<B> callback) { 57 mSource.loadInitial(params, new LoadInitialCallback<A>() { 58 @Override 59 public void onResult(@NonNull List<A> data, int position, int totalCount) { 60 callback.onResult(convert(mListFunction, data), position, totalCount); 61 } 62 63 @Override 64 public void onResult(@NonNull List<A> data, int position) { 65 callback.onResult(convert(mListFunction, data), position); 66 } 67 }); 68 } 69 70 @Override 71 public void loadRange(@NonNull LoadRangeParams params, 72 final @NonNull LoadRangeCallback<B> callback) { 73 mSource.loadRange(params, new LoadRangeCallback<A>() { 74 @Override 75 public void onResult(@NonNull List<A> data) { 76 callback.onResult(convert(mListFunction, data)); 77 } 78 }); 79 } 80} 81