/**
    * This file Copyright (c) 2017 Magnolia International
    * Ltd.  (http://www.magnolia-cms.com). All rights reserved.
    *
    *
    * This file is dual-licensed under both the Magnolia
    * Network Agreement and the GNU General Public License.
    * You may elect to use one or the other of these licenses.
    *
   * This file is distributed in the hope that it will be
   * useful, but AS-IS and WITHOUT ANY WARRANTY; without even the
   * implied warranty of MERCHANTABILITY or FITNESS FOR A
   * PARTICULAR PURPOSE, TITLE, or NONINFRINGEMENT.
   * Redistribution, except as permitted by whichever of the GPL
   * or MNA you select, is prohibited.
   *
   * 1. For the GPL license (GPL), you can redistribute and/or
   * modify this file under the terms of the GNU General
   * Public License, Version 3, as published by the Free Software
   * Foundation.  You should have received a copy of the GNU
   * General Public License, Version 3 along with this program;
   * if not, write to the Free Software Foundation, Inc., 51
   * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
   *
   * 2. For the Magnolia Network Agreement (MNA), this file
   * and the accompanying materials are made available under the
   * terms of the MNA which accompanies this distribution, and
   * is available at http://www.magnolia-cms.com/mna.html
   *
   * Any modifications to this file must keep this entire header
   * intact.
   *
   */
  package info.magnolia.module.cache.factory;
  
  import info.magnolia.module.cache.Cache;
  import info.magnolia.module.cache.CacheFactory;
  
  import java.util.ArrayList;
  import java.util.Collection;
  import java.util.List;
  
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  /**
   * Delegating {@link info.magnolia.module.cache.CacheFactory} which delegates to another factories until the cache with requested name is found.
   */
  public class DelegatingCacheFactory implements CacheFactory {
  
      private final Logger log = LoggerFactory.getLogger(DelegatingCacheFactory.class);
  
      private List<CacheFactory> delegateFactories = new ArrayList<>();
  
      @Override
      public Cache getCache(String name) {
          for (CacheFactory cacheFactory : delegateFactories) {
              if (cacheFactory.getCache(name) != null) {
                  return cacheFactory.getCache(name);
              }
          }
          return new NullCache();
      }
  
      @Override
      public void start(boolean isRestart) {
          for (CacheFactory cacheFactory : delegateFactories) {
              cacheFactory.start(isRestart);
          }
      }
  
      @Override
      public void stop(boolean isRestart) {
          for (CacheFactory cacheFactory : delegateFactories) {
              cacheFactory.stop(isRestart);
          }
      }
  
      @Override
      public List<String> getCacheNames() {
          List<String> cacheNames = new ArrayList<>();
          for (CacheFactory cacheFactory : delegateFactories) {
              cacheNames.addAll(cacheFactory.getCacheNames());
          }
          return cacheNames;
      }
  
      public void init() {
          if (delegateFactories.isEmpty()) {
              log.warn("No cache factory configured. Please install a cache implementation module");
          }
      }
  
      public List<CacheFactory> getDelegateFactories() {
          return delegateFactories;
      }
  
      public void setDelegateFactories(List<CacheFactory> delegateFactories) {
          this.delegateFactories = delegateFactories;
     }
 
     /**
      * Fallback cache object.
      */
     class NullCache implements Cache {
 
         @Override
         public boolean hasElement(Object key) {
             return false;
         }
 
         @Override
         public void put(Object key, Object value) {
         }
 
         @Override
         public void put(Object key, Object value, int timeToLiveInSeconds) {
         }
 
         @Override
         public Object get(Object key) {
             return null;
         }
 
         @Override
         public Object getQuiet(Object key) {
             return null;
         }
 
         @Override
         public void remove(Object key) {
         }
 
         @Override
         public void clear() {
         }
 
         @Override
         public String getName() {
             return null;
         }
 
         @Override
         public int getSize() {
             return 0;
         }
 
         @Override
         public Collection<Object> getKeys() {
             return null;
         }
     }
 }