package com.atlassian.cache.memory.jmx;
   
   import com.atlassian.cache.CacheManager;
   import com.atlassian.cache.CacheStatisticsKey;
   
   import javax.annotation.Nonnull;
   
   /**
    * JMX MBean implementation for Guava Cache
   *
   * @since v3.1
   */
  public class MemoryCacheMXBeanImpl implements MemoryCacheMXBean
  {
      
      private CacheManager cacheManager;
      private String cacheName;
  
  
      public MemoryCacheMXBeanImpl(@Nonnull CacheManager cacheManager, @Nonnull String cacheName)
      {
          this.cacheManager = cacheManager;
          this.cacheName = cacheName;
      }
  
      @Override
      public long getRequestCount()
      {
          return getProperty(CacheStatisticsKey.REQUEST_COUNT, 0L);
      }
  
      @Override
      public long getHitCount()
      {
          return getProperty(CacheStatisticsKey.HIT_COUNT, 0L);
      }
  
      @Override
      public double getHitRate()
      {
          long requestCount = getRequestCount();
          return (requestCount == 0) ? 1.0 : (double) getHitCount() / requestCount;
      }
  
      @Override
      public long getMissCount()
      {
          return getProperty(CacheStatisticsKey.MISS_COUNT, 0L);
      }
  
      @Override
      public double getMissRate()
      {
          long requestCount = getRequestCount();
          return (requestCount == 0) ? 0.0 : (double) getMissCount() / requestCount;
      }
  
      @Override
      public long getLoadCount()
      {
          return getProperty(CacheStatisticsKey.LOAD_COUNT, 0L);
      }
  
      @Override
      public long getLoadSuccessCount()
      {
          return getProperty(CacheStatisticsKey.LOAD_SUCCESS_COUNT, 0L);
      }
  
      @Override
      public long getLoadExceptionCount()
      {
          return getProperty(CacheStatisticsKey.LOAD_EXCEPTION_COUNT, 0L);
      }
  
      @Override
      public double getLoadExceptionRate()
      {
          long loadSuccessCount = getLoadSuccessCount();
          long loadExceptionCount = getLoadExceptionCount();
          long totalLoadCount = loadSuccessCount + loadExceptionCount;
          return (totalLoadCount == 0) ? 0.0 : (double) loadExceptionCount / totalLoadCount;
      }
  
      @Override
      public long getTotalLoadTime()
      {
          return getProperty(CacheStatisticsKey.TOTAL_LOAD_TIME, 0L);
      }
  
      @Override
      public double getAverageLoadPenalty()
      {
          long totalLoadCount = getLoadSuccessCount() + getLoadExceptionCount();
          return (totalLoadCount == 0) ? 0.0 : (double) getTotalLoadTime() / totalLoadCount;
      }
  
      @Override
      public long getEvictionCount()
     {
         return getProperty(CacheStatisticsKey.EVICTION_COUNT, 0L);
     }
 
     @Override
     public long getSize()
     {
         return getProperty(CacheStatisticsKey.SIZE, 0L);
     }
 
     private long getProperty(CacheStatisticsKey propertyName, long defaultValue)
     {
         if(cacheManager.getManagedCache(cacheName) == null
                 || cacheManager.getManagedCache(cacheName).getStatistics().get(propertyName) == null)
         {
             return defaultValue;
         }
         return cacheManager.getManagedCache(cacheName).getStatistics().get(propertyName).get();
     }
 }