9a4c66d23b
This is an abstract class for building a set of callback behavior based on Lifecycle status change. Through extending this class, the implemented methods are invoked only when required. Bug: 229689535 Test: unit test Change-Id: I7534393546f821738a63ebde121a5a88ee03b23b
101 lines
3.1 KiB
Java
101 lines
3.1 KiB
Java
/*
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* Copyright (C) 2022 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package com.android.settings.network.helper;
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import androidx.annotation.MainThread;
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import androidx.annotation.NonNull;
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import androidx.annotation.VisibleForTesting;
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import androidx.lifecycle.Lifecycle;
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import androidx.lifecycle.LifecycleEventObserver;
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import androidx.lifecycle.LifecycleOwner;
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import java.util.concurrent.atomic.AtomicReference;
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/**
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* A {@link androidx.lifecycle.LifecycleObserver} implementation of adapter over callback.
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*
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* Which including:
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* 1. Request to active callback when Lifecycle.State.STARTED
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* 2. Request to inactive callback when Lifecycle.State.STOPPED
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* 3. Close (no further resume) when Lifecycle.State.DESTROYED
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*/
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@VisibleForTesting
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abstract class LifecycleCallbackAdapter implements LifecycleEventObserver, AutoCloseable {
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private static final String TAG = "LifecycleCallbackAdapter";
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private AtomicReference<Lifecycle> mLifecycle = new AtomicReference<Lifecycle>();
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/**
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* Constructor
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* @param lifecycle {@link Lifecycle} to monitor
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*/
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@VisibleForTesting
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protected LifecycleCallbackAdapter(@NonNull Lifecycle lifecycle) {
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mLifecycle.set(lifecycle);
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lifecycle.addObserver(this);
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}
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/**
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* Get {@link Lifecycle} under monitor.
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* @return {@link Lifecycle}. Return {@code null} when closed.
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*/
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@VisibleForTesting
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public Lifecycle getLifecycle() {
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return mLifecycle.get();
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}
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/**
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* Check current callback status.
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* @return true when callback is active.
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*/
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public abstract boolean isCallbackActive();
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/**
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* Change callback status.
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* @param isActive true to active callback, otherwise inactive.
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*/
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public abstract void setCallbackActive(boolean isActive);
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/**
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* Implementation of LifecycleEventObserver.
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*/
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public void onStateChanged(LifecycleOwner source, Lifecycle.Event event) {
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if (mLifecycle.get() == null) {
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return;
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}
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Lifecycle.State state = event.getTargetState();
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boolean expectCallbackActive = state.isAtLeast(Lifecycle.State.STARTED);
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if (expectCallbackActive != isCallbackActive()) {
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setCallbackActive(expectCallbackActive);
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}
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if (state == Lifecycle.State.DESTROYED) {
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close();
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}
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}
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/**
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* Implementation of AutoCloseable.
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*/
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@MainThread
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public void close() {
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Lifecycle lifecycle = mLifecycle.getAndSet(null);
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if (lifecycle != null) {
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lifecycle.removeObserver(this);
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}
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}
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}
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