text: /**
   * Copyright 2010-present Facebook.
   *
   * 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.facebook;
  
  /**
   * <p>
   * Identifies the state of a Session.
   * </p>
   * <p>
   * Session objects implement a state machine that controls their lifecycle. This
   * enum represents the states of the state machine.
   * </p>
   */
  public enum SessionState {
      /**
       * Indicates that the Session has not yet been opened and has no cached
       * token. Opening a Session in this state will involve user interaction.
       */
      CREATED(Category.CREATED_CATEGORY),
  
      /**
       * <p>
       * Indicates that the Session has not yet been opened and has a cached
       * token. Opening a Session in this state will not involve user interaction.
       * </p>
       * <p>
       * If you are using Session from an Android Service, you must provide a
       * TokenCachingStrategy implementation that contains a valid token to the Session
       * constructor. The resulting Session will be created in this state, and you
       * can then safely call open, passing null for the Activity.
       * </p>
       */
      CREATED_TOKEN_LOADED(Category.CREATED_CATEGORY),
  
      /**
       * Indicates that the Session is in the process of opening.
       */
      OPENING(Category.CREATED_CATEGORY),
  
      /**
       * Indicates that the Session is opened. In this state, the Session may be
       * used with a {@link Request}.
       */
      OPENED(Category.OPENED_CATEGORY),
  
      /**
       * <p>
       * Indicates that the Session is opened and that the token has changed. In
       * this state, the Session may be used with {@link Request}.
       * </p>
       * <p>
       * Every time the token is updated, {@link Session.StatusCallback
       * StatusCallback} is called with this value.
       * </p>
       */
      OPENED_TOKEN_UPDATED(Category.OPENED_CATEGORY),
  
      /**
       * Indicates that the Session is closed, and that it was not closed
       * normally. Typically this means that the open call failed, and the
       * Exception parameter to {@link Session.StatusCallback StatusCallback} will
       * be non-null.
       */
      CLOSED_LOGIN_FAILED(Category.CLOSED_CATEGORY),
  
      /**
       * Indicates that the Session was closed normally.
       */
      CLOSED(Category.CLOSED_CATEGORY);
  
      private final Category category;
  
      SessionState(Category category) {
          this.category = category;
      }
  
      /**
       * Returns a boolean indicating whether the state represents a successfully
       * opened state in which the Session can be used with a {@link Request}.
       * 
       * @return a boolean indicating whether the state represents a successfully
       *         opened state in which the Session can be used with a
       *         {@link Request}.
       */
      public boolean isOpened() {
          return this.category == Category.OPENED_CATEGORY;
      }
  
      /**
       * Returns a boolean indicating whether the state represents a closed
       * Session that can no longer be used with a {@link Request}.
       * 
       * @return a boolean indicating whether the state represents a closed
       * Session that can no longer be used with a {@link Request}.
       */
      public boolean isClosed() {
          return this.category == Category.CLOSED_CATEGORY;
      }
  
      private enum Category {
          CREATED_CATEGORY, OPENED_CATEGORY, CLOSED_CATEGORY
      }
  }
  