| /* |
| * 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.utils; |
| |
| import android.annotation.Nullable; |
| |
| /** |
| * This class receives notifications when watched objects detect changes. |
| * Must be implemented by objects which are registered to a {@link Watchable}. |
| */ |
| public abstract class Watcher { |
| |
| /** |
| * This method is called when {@link Watchable} detects a change. The <what> |
| * parameter indicates what changed, but it may be null. The parameter is intended |
| * for debugging. |
| * |
| * @param what The {@link Watchable} that changed. |
| */ |
| public abstract void onChange(@Nullable Watchable what); |
| } |