ApplicationLifecycleMonitorRegistry.java
/*
* Copyright (C) 2014 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 androidx.test.runner.lifecycle;
import java.util.concurrent.atomic.AtomicReference;
/**
* An exposed registry instance to make it easy for callers to find the application lifecycle
* monitor for their application.
*/
public final class ApplicationLifecycleMonitorRegistry {
private static final AtomicReference<ApplicationLifecycleMonitor> lifecycleMonitor =
new AtomicReference<ApplicationLifecycleMonitor>(null);
// singleton - disallow creation
private ApplicationLifecycleMonitorRegistry() {}
/**
* Returns the ActivityLifecycleMonitor.
*
* <p>This monitor is not guaranteed to be present under all instrumentations.
*
* @return ActivityLifecycleMonitor the monitor for this application.
* @throws IllegalStateException if no monitor has been registered.
*/
public static ApplicationLifecycleMonitor getInstance() {
ApplicationLifecycleMonitor instance = lifecycleMonitor.get();
if (null == instance) {
throw new IllegalStateException(
"No lifecycle monitor registered! Are you running "
+ "under an Instrumentation which registers lifecycle monitors?");
}
return instance;
}
/**
* Stores a lifecycle monitor in the registry.
*
* <p>This is a global registry - so be aware of the impact of calling this method!
*
* @param monitor the monitor for this application. Null deregisters any existing monitor.
*/
public static void registerInstance(ApplicationLifecycleMonitor monitor) {
lifecycleMonitor.set(monitor);
}
}