1/*
2 * Copyright 2017 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.recyclerview.selection;
18
19import androidx.annotation.NonNull;
20
21/**
22 * Subclass of {@link Selection} exposing public support for mutating the underlying
23 * selection data. This is useful for clients of {@link SelectionTracker} that wish to
24 * manipulate a copy of selection data obtained via
25 * {@link SelectionTracker#copySelection(MutableSelection)}.
26 *
27 * <p>
28 * While the {@link Selection} class is not intrinsically immutable, it is not mutable
29 * by non-library code. Furthermore the value returned from {@link SelectionTracker#getSelection()}
30 * is a live view of the underlying selection, mutable by the library itself.
31 *
32 * <p>
33 * {@link MutableSelection} allows clients to obtain a mutable copy of the Selection
34 * state held by the selection library. This is useful in situations where a stable
35 * snapshot of the selection is required.
36 *
37 *
38 * <p><b>Example</b>
39 *
40 * <p>
41 * <pre>
42 * MutableSelection snapshot = new MutableSelection();
43 * selectionTracker.copySelection(snapshot);
44 *
45 * // Clear the user visible selection.
46 * selectionTracker.clearSelection();
47 * // tracker.getSelection().isEmpty() will be true.
48 * // shapshot has a copy of the previous selection.
49 * </pre>
50 *
51 * @see android.text.Selection
52 *
53 * @param <K> Selection key type. @see {@link StorageStrategy} for supported types.
54 */
55public final class MutableSelection<K> extends Selection<K> {
56
57    @Override
58    public boolean add(@NonNull K key) {
59        return super.add(key);
60    }
61
62    @Override
63    public boolean remove(@NonNull K key) {
64        return super.remove(key);
65    }
66
67    @Override
68    public void copyFrom(@NonNull Selection<K> source) {
69        super.copyFrom(source);
70    }
71
72    @Override
73    public void clear() {
74        super.clear();
75    }
76}
77