package com.atlassian.core.util.thumbnail;
   
   import com.google.common.annotations.VisibleForTesting;
   import com.google.common.base.Predicate;
   import org.apache.log4j.Logger;
   
   import javax.annotation.Nullable;
   
   public class AdaptiveThresholdPredicate implements Predicate<Dimensions>
  {
      private final static Logger log = Logger.getLogger(AdaptiveThresholdPredicate.class);
  
      private static final int BYTES_PER_PIXEL = 4;
      private static final float PROCESSING_HEADROOM = 1.2F; // We need a bit of headroom for processing, still pulling numbers out of thin air.
  
      @Override
      public boolean apply(@Nullable final Dimensions input)
      {
          return sufficientMemory(input);
      }
  
      private boolean sufficientMemory(final Dimensions dimensions)
      {
          long requiredMemory = dimensions.getHeight() * dimensions.getWidth() * BYTES_PER_PIXEL;
          long freeMemory = freeMemory();
          boolean result = requiredMemory * PROCESSING_HEADROOM < freeMemory;
          if (log.isDebugEnabled())
          {
              log.debug(String.format("Expected memory required for this image conversion: %d. " +
                      "Free memory: %d. Image dimension (%s) renderable: %s", requiredMemory, freeMemory, dimensions, result));
          }
          return result;
      }
  
      @VisibleForTesting
      long freeMemory()
      {
          return Runtime.getRuntime().freeMemory();
      }
  }