content: /*
   * Copyright (C) 2017 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.internal.telephony;
  
  import android.content.ContentResolver;
  import android.content.Context;
  import android.database.ContentObserver;
  import android.net.Uri;
  import android.os.Handler;
  import android.telephony.Rlog;
  
  import java.util.HashMap;
  import java.util.Map;
  
  /**
   * The class to describe settings observer
   */
  public class SettingsObserver extends ContentObserver {
      private final Map<Uri, Integer> mUriEventMap;
      private final Context mContext;
      private final Handler mHandler;
      private static final String TAG = "SettingsObserver";
  
      public SettingsObserver(Context context, Handler handler) {
          super(null);
          mUriEventMap = new HashMap<>();
          mContext = context;
          mHandler = handler;
      }
  
      /**
       * Start observing a content.
       * @param uri Content URI
       * @param what The event to fire if the content changes
       */
      public void observe(Uri uri, int what) {
          mUriEventMap.put(uri, what);
          final ContentResolver resolver = mContext.getContentResolver();
          resolver.registerContentObserver(uri, false, this);
      }
  
      /**
       * Stop observing a content.
       */
      public void unobserve() {
          final ContentResolver resolver = mContext.getContentResolver();
          resolver.unregisterContentObserver(this);
      }
  
      @Override
      public void onChange(boolean selfChange) {
          Rlog.e(TAG, "Should never be reached.");
      }
  
      @Override
      public void onChange(boolean selfChange, Uri uri) {
          final Integer what = mUriEventMap.get(uri);
          if (what != null) {
              mHandler.obtainMessage(what.intValue()).sendToTarget();
          } else {
              Rlog.e(TAG, "No matching event to send for URI=" + uri);
          }
      }
  }
  