content: /*
   * 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.google.android.exoplayer2.util;
  
  import android.os.Handler;
  import android.os.Looper;
  import android.support.annotation.Nullable;
  
  /**
   * An interface through which system clocks can be read and {@link HandlerWrapper}s created. The
   * {@link #DEFAULT} implementation must be used for all non-test cases.
   */
  public interface Clock {
  
    /**
     * Default {@link Clock} to use for all non-test cases.
     */
    Clock DEFAULT = new SystemClock();
  
    /** @see android.os.SystemClock#elapsedRealtime() */
    long elapsedRealtime();
  
    /** @see android.os.SystemClock#uptimeMillis() */
    long uptimeMillis();
  
    /** @see android.os.SystemClock#sleep(long) */
    void sleep(long sleepTimeMs);
  
    /**
     * Creates a {@link HandlerWrapper} using a specified looper and a specified callback for handling
     * messages.
     *
     * @see Handler#Handler(Looper, Handler.Callback)
     */
    HandlerWrapper createHandler(Looper looper, @Nullable Handler.Callback callback);
  }
  