Merge "Add LocalManagerRegistry inside system server."

package com.android.server {

  public final class LocalManagerRegistry {

    method public static <T> void addManager(@NonNull Class<T>, @NonNull T);

    method @Nullable public static <T> T getManager(@NonNull Class<T>);

  }

  public abstract class SystemService {

    ctor public SystemService(@NonNull android.content.Context);

    method @NonNull public final android.content.Context getContext();

// Signature format: 2.0

package com.android.server {

  public final class LocalManagerRegistry {

    method public static <T> void addManager(@NonNull Class<T>, @NonNull T);

    method @Nullable public static <T> T getManager(@NonNull Class<T>);

  }

  public abstract class SystemService {

    ctor public SystemService(@NonNull android.content.Context);

    method @NonNull public final android.content.Context getContext();

/*

 * Copyright (C) 2020 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.server;

import android.annotation.NonNull;

import android.annotation.Nullable;

import android.annotation.SystemApi;

import android.util.ArrayMap;

import java.util.Map;

import java.util.Objects;

/**

 * The registry for in-process module interfaces.

 * <p>

 * In-process module interfaces should be named with the suffix {@code ManagerLocal} for

 * consistency.

 *

 * @hide

 */

@SystemApi(client = SystemApi.Client.SYSTEM_SERVER)

public final class LocalManagerRegistry {

    private LocalManagerRegistry() {}

    @NonNull

    private static final Map<Class<?>, Object> sManagers = new ArrayMap<>();

    /**

     * Get a manager from the registry.

     *

     * @param managerClass the class that the manager implements

     * @return the manager, or {@code null} if not found

     */

    @Nullable

    @SuppressWarnings("unchecked")

    public static <T> T getManager(@NonNull Class<T> managerClass) {

        synchronized (sManagers) {

            return (T) sManagers.get(managerClass);

        }

    }

    /**

     * Adds a manager to the registry.

     *

     * @param managerClass the class that the manager implements

     * @param manager the manager

     * @throws IllegalStateException if the manager class is already registered

     */

    public static <T> void addManager(@NonNull Class<T> managerClass, @NonNull T manager) {

        Objects.requireNonNull(managerClass, "managerClass");

        Objects.requireNonNull(manager, "manager");

        synchronized (sManagers) {

            if (sManagers.containsKey(managerClass)) {

                throw new IllegalStateException(managerClass.getName() + " is already registered");

            }

            sManagers.put(managerClass, manager);

        }

    }

}