| /* |
| * Copyright (C) 2019 The Android Open Source Project |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| package com.android.internal.util; |
| |
| import android.annotation.Nullable; |
| import android.os.Parcel; |
| import android.util.ArrayMap; |
| |
| import java.util.regex.Pattern; |
| |
| /** |
| * Describes a 2-way parcelling contract of type {@code T} into/out of a {@link Parcel} |
| * |
| * Implementations should be stateless. |
| * |
| * @param <T> the type being [un]parcelled |
| */ |
| public interface Parcelling<T> { |
| |
| /** |
| * Write an item into parcel. |
| */ |
| void parcel(T item, Parcel dest, int parcelFlags); |
| |
| /** |
| * Read an item from parcel. |
| */ |
| T unparcel(Parcel source); |
| |
| |
| /** |
| * A registry of {@link Parcelling} singletons. |
| */ |
| class Cache { |
| private Cache() {} |
| |
| private static ArrayMap<Class, Parcelling> sCache = new ArrayMap<>(); |
| |
| /** |
| * Retrieves an instance of a given {@link Parcelling} class if present. |
| */ |
| public static @Nullable <P extends Parcelling<?>> P get(Class<P> clazz) { |
| return (P) sCache.get(clazz); |
| } |
| |
| /** |
| * Stores an instance of a given {@link Parcelling}. |
| * |
| * @return the provided parcelling for convenience. |
| */ |
| public static <P extends Parcelling<?>> P put(P parcelling) { |
| sCache.put(parcelling.getClass(), parcelling); |
| return parcelling; |
| } |
| |
| /** |
| * Produces an instance of a given {@link Parcelling} class, by either retrieving a cached |
| * instance or reflectively creating one. |
| */ |
| public static <P extends Parcelling<?>> P getOrCreate(Class<P> clazz) { |
| // No synchronization - creating an extra instance in a race case is ok |
| P cached = get(clazz); |
| if (cached != null) { |
| return cached; |
| } else { |
| try { |
| return put(clazz.newInstance()); |
| } catch (Exception e) { |
| throw new RuntimeException(e); |
| } |
| } |
| } |
| } |
| |
| /** |
| * Common {@link Parcelling} implementations. |
| */ |
| interface BuiltIn { |
| |
| class ForPattern implements Parcelling<Pattern> { |
| |
| @Override |
| public void parcel(Pattern item, Parcel dest, int parcelFlags) { |
| dest.writeString(item == null ? null : item.pattern()); |
| } |
| |
| @Override |
| public Pattern unparcel(Parcel source) { |
| String s = source.readString(); |
| return s == null ? null : Pattern.compile(s); |
| } |
| } |
| } |
| } |