common/src/com/android/tv/common/util/Clock.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 com.android.tv.common.util;

import android.os.SystemClock;

/**
 * An interface through which system clocks can be read. The {@link #SYSTEM} implementation must be
 * used for all non-test cases.
 */
public interface Clock {
    /**
     * Returns the current time in milliseconds since January 1, 1970 00:00:00.0 UTC.
     *
     * @see System#currentTimeMillis().
     */
    long currentTimeMillis();

    /**
     * Returns milliseconds since boot, including time spent in sleep.
     *
     * @see SystemClock#elapsedRealtime()
     */
    long elapsedRealtime();

    /**
     * Returns milliseconds since boot, not counting time spent in deep sleep.
     *
     * @return milliseconds of non-sleep uptime since boot.
     * @see SystemClock#uptimeMillis()
     */
    long uptimeMillis();

    /**
     * Waits a given number of milliseconds (of uptimeMillis) before returning.
     *
     * @param ms to sleep before returning, in milliseconds of uptime.
     * @see SystemClock#sleep(long)
     */
    void sleep(long ms);

    /** The default implementation of Clock. */
    Clock SYSTEM =
            new Clock() {
                @Override
                public long currentTimeMillis() {
                    return System.currentTimeMillis();
                }

                @Override
                public long elapsedRealtime() {
                    return SystemClock.elapsedRealtime();
                }

                @Override
                public void sleep(long ms) {
                    SystemClock.sleep(ms);
                }

                @Override
                public long uptimeMillis() {
                    return SystemClock.uptimeMillis();
                }
            };
}