content: /*
   *  Licensed to the Apache Software Foundation (ASF) under one
   *  or more contributor license agreements.  See the NOTICE file
   *  distributed with this work for additional information
   *  regarding copyright ownership.  The ASF licenses this file
   *  to you 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 org.apache.causeway.applib.services.user;
  
  import java.time.ZoneId;
  import java.util.Optional;
  
  import org.jspecify.annotations.NonNull;
  
  /**
   * Stores the user's current {@link ZoneId} with session scope.
   * <p>
   * eg. on application login
   *
   * @since 2.0 {@index}
   */
  public interface UserCurrentSessionTimeZoneHolder {
  
      /**
       * Sets the user's current {@link ZoneId}
       * within the context of the current session.
       */
      void setUserTimeZone(@NonNull ZoneId zoneId);
  
      /**
       * Optionally returns the user's current {@link ZoneId},
       * based on whether it was set before,
       * within the context of the current session.
       *
       * @apiNote not meant to fallback to system defaults,
       * instead return {@link Optional#empty()},
       * if there is no specific time-zone information available
       */
      Optional<ZoneId> getUserTimeZone();
  
      /**
       * Clears the user's current {@link ZoneId}
       * within the context of the current session.
       */
      void clearUserTimeZone();
  
  }