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 17 package androidx.recyclerview.selection; 18 19 import 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 */ 55 public 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
