package com.atlassian.cache.impl;
   
   import com.atlassian.cache.CacheEntryListener;
   
   import java.util.Set;
   import java.util.concurrent.CopyOnWriteArraySet;
   
   import static com.google.common.base.Preconditions.checkNotNull;
   
  /**
   * A utility class which:
   * <ul>
   *     <li>Manages a set of {@code CacheEntryListener}s</li>
   *     <li>Provides a way to notify these listeners about different events</li>
   * </ul>
   */
  public class DefaultCacheEntryListenerSupport<K, V> implements CacheEntryListenerSupport<K, V>
  {
      private final Set<CacheEntryListener<K, V>> listeners = new CopyOnWriteArraySet<CacheEntryListener<K, V>>();
      private final CacheEntryNotificationSupport notificationSupport = CacheEntryNotificationSupport.getInstance();
  
      public void add(CacheEntryListener<K, V> listener, boolean includeValues)
      {
          listeners.add(checkNotNull(listener));
      }
  
      public void remove(CacheEntryListener<K, V> listener)
      {
          listeners.remove(checkNotNull(listener));
      }
  
      public void notifyAdd(K key, V value)
      {
          notificationSupport.notifyAdd(listeners, new DefaultCacheEntryEvent<K, V>(key, value, null));
      }
  
      public void notifyEvict(K key, V oldValue)
      {
          notificationSupport.notifyEvict(listeners, new DefaultCacheEntryEvent<K, V>(key, null, oldValue));
      }
  
      public void notifyRemove(K key, V oldValue)
      {
          notificationSupport.notifyRemove(listeners, new DefaultCacheEntryEvent<K, V>(key, null, oldValue));
      }
  
      public void notifyUpdate(K key, V value, V oldValue)
      {
          notificationSupport.notifyUpdate(listeners, new DefaultCacheEntryEvent<K, V>(key, value, oldValue));
      }
  }