content: /*
   * Copyright (C) 2016 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
   */
  
  /**
   * The Android Telecom framework is responsible for managing calls on an Android device.  This can
   * include SIM-based calls using the {@code Telephony} framework, VOIP calls using SIP (e.g. the
   * {@code SipConnectionService}), or via a third-party VOIP
   * {@link android.telecom.ConnectionService}.  Telecom acts as a switchboard, routing calls and
   * audio focus between {@link android.telecom.Connection}s provided by
   * {@link android.telecom.ConnectionService} implementations, and
   * {@link android.telecom.InCallService} implementations which provide a user interface for calls.
   * <p>
   * Android supports the following calling use cases (with increasing level of complexity):
   * <ul>
   *     <li>Implement the self-managed {@link android.telecom.ConnectionService} API - this is ideal
   *     for developers of standalone calling apps which do not wish to show their calls within the
   *     default phone app, and do not wish to have other calls shown in their user interface.  Using
   *     a self-managed {@link android.telecom.ConnectionService} implementation within your
   *     standalone calling app helps you ensure that your app will interoperate not only with native
   *     telephony calling on the device, but also other standalone calling apps implementing this
   *     API.  It also manages audio routing and focus for you.</li>
   *     <li>Implement the managed {@link android.telecom.ConnectionService} API - facilitates
   *     development of a calling solution that relies on the existing device phone application (see
   *     {@link android.telecom.TelecomManager#getDefaultDialerPackage()}) to provide the user
   *     interface for calls.  An example might be a third party implementation of SIP calling, or a
   *     VOIP calling service.  A {@link android.telecom.ConnectionService} alone provides only the
   *     means of connecting calls, but has no associated user interface.</li>
   *     <li>Implement the {@link android.telecom.InCallService} API - facilitates development of a
   *     replacement for the device's default Phone/Dialer app.  The
   *     {@link android.telecom.InCallService} alone does not have any calling capability and consists
   *     of the user-interface side of calling only.  An {@link android.telecom.InCallService} must
   *     handle all Calls the Telecom framework is aware of.  It must not make assumptions about the
   *     nature of the calls (e.g. assuming calls are SIM-based telephony calls), and should not
   *     implement calling restrictions based on any one {@link android.telecom.ConnectionService}
   *     (e.g. it should not enforce Telephony restrictions for video calls).</li>
   *     <li>Implement both the {@link android.telecom.InCallService} and
   *     {@link android.telecom.ConnectionService} API - ideal if you wish to create your own
   *     {@link android.telecom.ConnectionService} based calling solution, complete with its own
   *     full user interface, while showing all other Android calls in the same user interface.  Using
   *     this approach, you must still ensure that your {@link android.telecom.InCallService} makes
   *     no assumption about the source of the calls it displays.  You must also ensure that your
   *     {@link android.telecom.ConnectionService} implementation can still function without the
   *     default phone app being set to your custom {@link android.telecom.InCallService}.</li>
   * </ul>
   */
  package android.telecom;