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