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.annotation.Nullable;
21import androidx.arch.core.util.Function;
22
23import java.util.List;
24
25class WrapperPageKeyedDataSource<K, A, B> extends PageKeyedDataSource<K, B> {
26    private final PageKeyedDataSource<K, A> mSource;
27    private final Function<List<A>, List<B>> mListFunction;
28
29    WrapperPageKeyedDataSource(PageKeyedDataSource<K, A> source,
30            Function<List<A>, List<B>> listFunction) {
31        mSource = source;
32        mListFunction = listFunction;
33    }
34
35    @Override
36    public void addInvalidatedCallback(@NonNull InvalidatedCallback onInvalidatedCallback) {
37        mSource.addInvalidatedCallback(onInvalidatedCallback);
38    }
39
40    @Override
41    public void removeInvalidatedCallback(@NonNull InvalidatedCallback onInvalidatedCallback) {
42        mSource.removeInvalidatedCallback(onInvalidatedCallback);
43    }
44
45    @Override
46    public void invalidate() {
47        mSource.invalidate();
48    }
49
50    @Override
51    public boolean isInvalid() {
52        return mSource.isInvalid();
53    }
54
55    @Override
56    public void loadInitial(@NonNull LoadInitialParams<K> params,
57            final @NonNull LoadInitialCallback<K, B> callback) {
58        mSource.loadInitial(params, new LoadInitialCallback<K, A>() {
59            @Override
60            public void onResult(@NonNull List<A> data, int position, int totalCount,
61                    @Nullable K previousPageKey, @Nullable K nextPageKey) {
62                callback.onResult(convert(mListFunction, data), position, totalCount,
63                        previousPageKey, nextPageKey);
64            }
65
66            @Override
67            public void onResult(@NonNull List<A> data, @Nullable K previousPageKey,
68                    @Nullable K nextPageKey) {
69                callback.onResult(convert(mListFunction, data), previousPageKey, nextPageKey);
70            }
71        });
72    }
73
74    @Override
75    public void loadBefore(@NonNull LoadParams<K> params,
76            final @NonNull LoadCallback<K, B> callback) {
77        mSource.loadBefore(params, new LoadCallback<K, A>() {
78            @Override
79            public void onResult(@NonNull List<A> data, @Nullable K adjacentPageKey) {
80                callback.onResult(convert(mListFunction, data), adjacentPageKey);
81            }
82        });
83    }
84
85    @Override
86    public void loadAfter(@NonNull LoadParams<K> params,
87            final @NonNull LoadCallback<K, B> callback) {
88        mSource.loadAfter(params, new LoadCallback<K, A>() {
89            @Override
90            public void onResult(@NonNull List<A> data, @Nullable K adjacentPageKey) {
91                callback.onResult(convert(mListFunction, data), adjacentPageKey);
92            }
93        });
94    }
95}
96