/*
 * Copyright 2011 Red Hat, Inc. and/or its affiliates.
 *
 * This is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation; either version 2.1 of
 * the License, or (at your option) any later version.
 *
 * This software is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
 * 02110-1301 USA
 */
package org.infinispan.configuration.cache;

import org.infinispan.config.ConfigurationException;
import org.infinispan.eviction.EvictionStrategy;
import org.infinispan.eviction.EvictionThreadPolicy;
import org.infinispan.util.logging.Log;
import org.infinispan.util.logging.LogFactory;

/**
 * Controls the eviction settings for the cache.
 */
public class EvictionConfigurationBuilder extends AbstractConfigurationChildBuilder<EvictionConfiguration> {

   private static final Log log = LogFactory.getLog(EvictionConfigurationBuilder.class);
   
   private int maxEntries = -1;
   private EvictionStrategy strategy = EvictionStrategy.NONE;
   private EvictionThreadPolicy threadPolicy = EvictionThreadPolicy.DEFAULT;
   
   EvictionConfigurationBuilder(ConfigurationBuilder builder) {
      super(builder);
   }

   
   /**
    * Eviction strategy. Available options are 'UNORDERED', 'LRU', 'LIRS' and 'NONE' (to disable
    * eviction).
    *
    * @param evictionStrategy
    */
   public EvictionConfigurationBuilder strategy(EvictionStrategy evictionStrategy) {
      this.strategy = evictionStrategy;
      return this;
   }
   
   /**
    * Threading policy for eviction.
    *
    * @param policy
    */
   public EvictionConfigurationBuilder threadPolicy(EvictionThreadPolicy policy) {
      this.threadPolicy = policy;
      return this;
   }
   
   /**
    * Maximum number of entries in a cache instance. Cache size is guaranteed not to exceed upper
    * limit specified by max entries. However, due to the nature of eviction it is unlikely to ever
    * be exactly maximum number of entries specified here.
    * 
    * @param maxEntries
    */
   public EvictionConfigurationBuilder maxEntries(int maxEntries) {
      this.maxEntries = maxEntries;
      return this;
   }

   @Override
   void validate() {
      if (!strategy.isEnabled() && getBuilder().loaders().passivation())
         log.passivationWithoutEviction();
      if(strategy == EvictionStrategy.FIFO)
         log.warn("FIFO strategy is deprecated, LRU will be used instead");
      if (strategy.isEnabled() && maxEntries <= 0)
         throw new ConfigurationException("Eviction maxEntries value cannot be less than or equal to zero if eviction is enabled");
      if (maxEntries > 0 && !strategy.isEnabled()) {
         strategy = EvictionStrategy.LIRS;
         log.debugf("Max entries configured (%d) without eviction strategy. Eviction strategy overriden to %s", maxEntries, strategy);
      }
   }

   @Override
   EvictionConfiguration create() {
      return new EvictionConfiguration(maxEntries, strategy, threadPolicy);
   }
   
   @Override
   public EvictionConfigurationBuilder read(EvictionConfiguration template) {
      this.maxEntries = template.maxEntries();
      this.strategy = template.strategy();
      this.threadPolicy = template.threadPolicy();
      
      return this;
   }

   @Override
   public String toString() {
      return "EvictionConfigurationBuilder{" +
            "maxEntries=" + maxEntries +
            ", strategy=" + strategy +
            ", threadPolicy=" + threadPolicy +
            '}';
   }

}