TimeGateway.java
/*
* Copyright 2022 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.wear.protolayout.expression.pipeline;
import androidx.annotation.NonNull;
import java.util.concurrent.Executor;
/**
* A gateway to Time data sources. This should call any provided callbacks every second.
*
* <p>Implementations of this class should track a few things:
*
* <ul>
* <li>Surface lifecycle. Implementations should keep track of registered consumers, and
* deregister them all when the surface is no longer available.
* <li>Device state. Implementations should react to device state (i.e. ambient mode), and
* activity state (i.e. is the surface in the foreground), and enable/disable updates
* accordingly.
* </ul>
*/
interface TimeGateway {
/** Callback for time notifications. */
interface TimeCallback {
/**
* Called just before an update happens. All onPreUpdate calls will be made before any
* onUpdate calls fire.
*
* <p>Will be called on the same executor passed to {@link TimeGateway#registerForUpdates}.
*/
void onPreUpdate();
/**
* Notifies that the current time has changed.
*
* <p>Will be called on the same executor passed to {@link TimeGateway#registerForUpdates}.
*/
void onData();
}
/** Register for time updates. All callbacks will be called on the provided executor. */
void registerForUpdates(@NonNull Executor executor, @NonNull TimeCallback callback);
/** Unregister for time updates. */
void unregisterForUpdates(@NonNull TimeCallback callback);
}