package com.atlassian.cache.impl;
   
   import java.io.Serializable;
   
   /**
   * Class used for type safe handling of lazy references in our cache implementation.
   *
   * @since 2.0
   */
  public class ReferenceKey implements Serializable
  {
      private static final long serialVersionUID = 3814781337421919991L;
  
      public static final ReferenceKey KEY = new ReferenceKey();
  
      // Constructor is private to prevent instantiation
      private ReferenceKey() {}
  
      @Override
      public boolean equals(final Object o)
      {
          return o instanceof ReferenceKey;
      }
  
      @Override
      public int hashCode()
      {
          return 0;
      }
  }