package com.atlassian.cache.hazelcast;
   
   import com.google.common.base.Objects;
   
   class Versioned<T>
   {
       @SuppressWarnings ("unchecked")
       private static final Versioned EMPTY = new Versioned(null, 0L);
   
      private final long version;
      private final T value;
  
      Versioned(T value, long version)
      {
          this.value = value;
          this.version = version;
      }
  
      @SuppressWarnings ("unchecked")
      public static <T> Versioned<T> empty()
      {
          return EMPTY;
      }
  
      public T getValue()
      {
          return value;
      }
  
      public long getVersion()
      {
          return version;
      }
  
      @Override
      public boolean equals(Object o)
      {
          if (this == o)
          {
              return true;
          }
          if (o == null || getClass() != o.getClass())
          {
              return false;
          }
  
          Versioned that = (Versioned) o;
          return Objects.equal(version, that.version) && Objects.equal(value, that.value);
      }
  
      @Override
      public int hashCode()
      {
          int result = (int) (version ^ (version >>> 32));
          result = 31 * result + (value != null ? value.hashCode() : 0);
          return result;
      }
  }