package com.atlassian.cache.impl;
   
   import com.atlassian.cache.CachedReferenceListener;
   import com.atlassian.util.concurrent.LazyReference;
   
   public class LazyCachedReferenceListenerSupport<V> implements CachedReferenceListenerSupport<V>
   {
       private final LazyReference<CachedReferenceListenerSupport<V>> lazyListenerSupport =
               new LazyReference<CachedReferenceListenerSupport<V>>()
              {
                  @Override
                  protected CachedReferenceListenerSupport<V> create() throws Exception
                  {
                      init();
                      return createDelegate();
                  }
              };
  
      protected void init()
      {
      }
  
      protected CachedReferenceListenerSupport<V> createDelegate()
      {
          return new DefaultCachedReferenceListenerSupport<V>();
      }
  
      private CachedReferenceListenerSupport<V> loadDelegate()
      {
          return lazyListenerSupport.get();
      }
  
      private CachedReferenceListenerSupport<V> getDelegate()
      {
          if (lazyListenerSupport.isInitialized())
          {
              return lazyListenerSupport.get();
          }
          else
          {
              return CachedReferenceListenerSupport.EMPTY;
          }
      }
  
      @Override
      public void add(CachedReferenceListener<V> listener, boolean includeValues)
      {
          loadDelegate().add(listener, includeValues);
      }
  
      @Override
      public void remove(CachedReferenceListener<V> listener)
      {
          getDelegate().remove(listener);
      }
  
      @Override
      public void notifyEvict(V oldValue)
      {
          getDelegate().notifyEvict(oldValue);
      }
  
      @Override
      public void notifySet(V value)
      {
          getDelegate().notifySet(value);
      }
  
      @Override
      public void notifyReset(V oldValue)
      {
          getDelegate().notifyReset(oldValue);
      }
  }