Estoy intentando incluir un mensaje adicional en mi intención de pasar al AlarmManager para que se active más adelante. Mi onReceive se dispara correctamente pero extras.getString () devuelve null

Preparar:

public PendingIntent getPendingIntent(int uniqueRequestCode, String extra) {
    Intent intent = new Intent(this, ActionReceiver.class);
    intent.putExtra("EXTRA", extra);
    PendingIntent pendingIntent = PendingIntent.getBroadcast(this, uniqueRequestCode,
            intent, 0);
    return pendingIntent;
}

public void setSilentLater(TimeRule timeRule) {
    boolean[] weekdays = timeRule.getReoccurringWeekdays();
    int dayOfWeek = 0;

    for (boolean day : weekdays) {
        dayOfWeek++;
        if (day == true) {
            Calendar cal = Calendar.getInstance();

            AlarmManager alarmManager = (AlarmManager) this
                    .getSystemService(Context.ALARM_SERVICE);

            cal.set(Calendar.DAY_OF_WEEK, dayOfWeek);
            cal.set(Calendar.HOUR_OF_DAY,
                    timeRule.getStartTime().get(Calendar.HOUR_OF_DAY));
            cal.set(Calendar.MINUTE,
                    timeRule.getStartTime().get(Calendar.MINUTE));
            cal.set(Calendar.SECOND, 0);
            cal.set(Calendar.MILLISECOND, 0);

            alarmManager.setRepeating(AlarmManager.RTC_WAKEUP,
                    cal.getTimeInMillis(), 3600000 * 7, getPendingIntent(0, "RINGER_OFF"));
  }
 }
}

Cuando esto se dispara, el mensaje está vacío:

public class ActionReceiver extends BroadcastReceiver {

    @Override
    public void onReceive(Context context, Intent intent) {
         Bundle extras = intent.getExtras();
         String message = extras.getString("EXTRA"); //empty        
         if(message == "RINGER_OFF")
         {
             AudioManager am = (AudioManager) context.getSystemService(Context.AUDIO_SERVICE);
             am.setRingerMode(AudioManager.RINGER_MODE_SILENT);
         }
         else if(message == "RINGER_ON")
         {
             AudioManager am = (AudioManager) context.getSystemService(Context.AUDIO_SERVICE);
             am.setRingerMode(AudioManager.RINGER_MODE_NORMAL);
         }
    }
}