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.calcite.chinook;
  
  /**
   * Fairy simulates environment around Calcite.
   *
   * <p>An example property is the user on whose behalf Calcite is running the
   * current query. Other properties can change from one query to another.
   * Properties are held in thread-locals, so it is safe to set a property then
   * read it from the same thread.
   */
  public class EnvironmentFairy {
  
    private static final ThreadLocal<User> USER =
        ThreadLocal.withInitial(() -> User.ADMIN);
  
    private EnvironmentFairy() {
    }
  
    public static User getUser() {
      return USER.get();
    }
  
    public static void login(User user) {
      USER.set(user);
    }
  
    /**
     * Describes who is emulated to being logged in.
     */
    public enum User {
      ADMIN, SPECIFIC_USER
    }
  
  }
  