package com.atlassian.cache.hazelcast;
   
   import java.util.Map;
   
   import com.hazelcast.map.AbstractEntryProcessor;
   
   class GetOrInitVersionEntryProcessor<K> extends AbstractEntryProcessor<K, Long>
   {
       private static GetOrInitVersionEntryProcessor<Object> INSTANCE = new GetOrInitVersionEntryProcessor<Object>();
  
      protected static <T> GetOrInitVersionEntryProcessor<T> getInstance()
      {
          //noinspection unchecked
          return (GetOrInitVersionEntryProcessor<T>) INSTANCE;
      }
  
      private GetOrInitVersionEntryProcessor()
      {
      }
  
      @Override
      public Object process(Map.Entry<K, Long> entry)
      {
          Long value = entry.getValue();
          if (value == null)
          {
              value = 1L;
              entry.setValue(value);
          }
          return value;
      }
  }