content: /*
   * Solo - A small and beautiful blogging system written in Java.
   * Copyright (c) 2010-present, b3log.org
   *
   * Solo is licensed under Mulan PSL v2.
   * You can use this software according to the terms and conditions of the Mulan PSL v2.
   * You may obtain a copy of Mulan PSL v2 at:
   *         http://license.coscl.org.cn/MulanPSL2
   * THIS SOFTWARE IS PROVIDED ON AN "AS IS" BASIS, WITHOUT WARRANTIES OF ANY KIND, EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO NON-INFRINGEMENT, MERCHANTABILITY OR FIT FOR A PARTICULAR PURPOSE.
   * See the Mulan PSL v2 for more details.
   */
  package org.b3log.solo.cache;
  
  import org.b3log.latke.Keys;
  import org.b3log.latke.ioc.Singleton;
  import org.b3log.solo.util.Solos;
  import org.json.JSONObject;
  
  import java.util.Map;
  import java.util.concurrent.ConcurrentHashMap;
  
  /**
   * Page cache.
   *
   * @author <a href="http://88250.b3log.org">Liang Ding</a>
   * @version 1.0.0.1, Sep 25, 2018
   * @since 2.3.0
   */
  @Singleton
  public class PageCache {
  
      /**
       * Page cache.
       */
      private final Map<String, JSONObject> cache = new ConcurrentHashMap<>();
  
      /**
       * Gets a page by the specified page id.
       *
       * @param id the specified page id
       * @return page, returns {@code null} if not found
       */
      public JSONObject getPage(final String id) {
          final JSONObject page = cache.get(id);
          if (null == page) {
              return null;
          }
  
          return Solos.clone(page);
      }
  
      /**
       * Adds or updates the specified page.
       *
       * @param page the specified page
       */
      public void putPage(final JSONObject page) {
          final String pageId = page.optString(Keys.OBJECT_ID);
  
          cache.put(pageId, Solos.clone(page));
      }
  
      /**
       * Removes an page by the specified page id.
       *
       * @param id the specified page id
       */
      public void removePage(final String id) {
          cache.remove(id);
      }
  
      /**
       * Clears all cached data.
       */
      public void clear() {
          cache.clear();
      }
  }
  