/***
    *  Copyright 2003-2010 Terracotta, Inc.
    *
    *  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 net.sf.ehcache.loader;
  
  import net.sf.ehcache.CacheException;
  import net.sf.ehcache.Ehcache;
  import net.sf.ehcache.Status;
  
  import java.util.Collection;
  import java.util.HashMap;
  import java.util.Iterator;
  import java.util.Map;
  import java.util.Random;
  
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  
  /***
   * A cache loader that counts the number of things it has loaded, useful for testing.
   * <p/>
   * <p/>
   * Each load has a random delay to introduce some nice threading entropy.
   *
   * @author Greg Luck
   * @version $Id: CountingCacheLoader.java 2154 2010-04-06 02:45:52Z cdennis $
   */
  public class CountingCacheLoader implements CacheLoader {
  
      private static final Logger LOG = LoggerFactory.getLogger(CountingCacheLoader.class.getName());
  
      private volatile int loadCounter;
      private volatile int loadAllCounter;
      private Random random = new Random();
      private String name = "CountingCacheLoader";
  
      /***
       * loads an object. Application writers should implement this
       * method to customize the loading of cache object. This method is called
       * by the caching service when the requested object is not in the cache.
       * <p/>
       *
       * @param key the key identifying the object being loaded
       * @return The object that is to be stored in the cache.
       *
       */
      public Object load(Object key) throws CacheException {
          try {
              Thread.sleep(random.nextInt(3) + 1);
          } catch (InterruptedException e) {
              LOG.error("Interrupted");
          }
          return Integer.valueOf(loadCounter++);
      }
  
      /***
       * loads multiple object. Application writers should implement this
       * method to customize the loading of cache object. This method is called
       * by the caching service when the requested object is not in the cache.
       * <p/>
       *
       * @param keys a Collection of keys identifying the objects to be loaded
       * @return A Map of objects that are to be stored in the cache.
       *
       */
  
      public Map loadAll(Collection keys) throws CacheException {
          Map map = new HashMap(keys.size());
          for (Iterator iterator = keys.iterator(); iterator.hasNext();) {
              Object key = iterator.next();
              try {
                  Thread.sleep(random.nextInt(4));
              } catch (InterruptedException e) {
                  LOG.error("Interrupted");
              }
              map.put(key, Integer.valueOf(loadAllCounter++));
          }
          return map;
      }
  
  
      /***
       * @return
       */
      public int getLoadCounter() {
         return loadCounter;
     }
 
     /***
      * @return
      */
     public int getLoadAllCounter() {
         return loadAllCounter;
     }
 
     /***
      * Load using both a key and an argument.
      * <p/>
      * JCache will use the load(key) method where the argument is null.
      *
      * @param key
      * @param argument
      * @return
      *
      */
     public Object load(Object key, Object argument) throws CacheException {
         try {
             Thread.sleep(random.nextInt(3) + 1);
         } catch (InterruptedException e) {
             LOG.error("Interrupted");
         }
         return name + ":" + argument;
     }
 
     /***
      * Load using both a key and an argument.
      * <p/>
      * JCache will use the loadAll(key) method where the argument is null.
      *
      * @param keys
      * @param argument
      * @return
      *
      */
     public Map loadAll(Collection keys, Object argument) throws CacheException {
         return loadAll(keys);
     }
 
     /***
      * Gets the name of a CacheLoader
      *
      * @return
      */
     public String getName() {
         return name;
     }
 
     /***
      * Creates a clone of this extension. This method will only be called by ehcache before a
      * cache is initialized.
      * <p/>
      * Implementations should throw CloneNotSupportedException if they do not support clone
      * but that will stop them from being used with defaultCache.
      *
      * @return a clone
      * @throws CloneNotSupportedException if the extension could not be cloned.
      */
     public CacheLoader clone(Ehcache cache) throws CloneNotSupportedException {
         return null;
     }
 
     /***
      * Notifies providers to initialise themselves.
      * <p/>
      * This method is called during the Cache's initialise method after it has changed it's
      * status to alive. Cache operations are legal in this method.
      *
      * @throws net.sf.ehcache.CacheException
      */
     public void init() {
         //nothing required
     }
 
     /***
      * Providers may be doing all sorts of exotic things and need to be able to clean up on
      * dispose.
      * <p/>
      * Cache operations are illegal when this method is called. The cache itself is partly
      * disposed when this method is called.
      *
      * @throws net.sf.ehcache.CacheException
      */
     public void dispose() throws net.sf.ehcache.CacheException {
         //nothing required
     }
 
     /***
      * @return the status of the extension
      */
     public Status getStatus() {
         return null;
     }
 
     /***
      * Sets the name
      */
     public void setName(String name) {
         this.name = name;
     }
 
 
 }