package com.atlassian.cache.hazelcast;
   
   import java.util.Map;
   
   import com.hazelcast.map.AbstractEntryProcessor;
   
   class IncrementVersionEntryProcessor<K> extends AbstractEntryProcessor<K, Long>
   {
       private static final IncrementVersionEntryProcessor<Object> INSTANCE =
              new IncrementVersionEntryProcessor<Object>(false);
      private static final IncrementVersionEntryProcessor<Object> UPDATING_INSTANCE =
              new IncrementVersionEntryProcessor<Object>(true);
  
      protected static <T> IncrementVersionEntryProcessor<T> getInstance()
      {
          return (IncrementVersionEntryProcessor<T>) INSTANCE;
      }
  
      protected static <T> IncrementVersionEntryProcessor<T> getUpdatingInstance()
      {
          return (IncrementVersionEntryProcessor<T>) UPDATING_INSTANCE;
      }
  
      private final boolean update;
  
      private IncrementVersionEntryProcessor(boolean update)
      {
          this.update = update;
      }
  
      @Override
      public Object process(Map.Entry<K, Long> entry)
      {
          Long value = entry.getValue();
          value = value == null ? 1L : value + 1L;
          if (update)
          {
              entry.setValue(value);
          }
          return value;
      }
  }