package com.atlassian.core.util.thumbnail.loader;
   
   import com.atlassian.core.util.ImageInfo;
   import com.atlassian.core.util.ReusableBufferedInputStream;
   import com.google.common.base.Optional;
   import com.google.common.collect.ImmutableList;
   
   import java.awt.image.BufferedImage;
   import java.io.IOException;
  import java.util.List;
  
  public class ImageFactory
  {
  
      /**
       * Instances of all available image loaders. Loaders will be run in sequence and
       * first not null BufferedImage instance will be returned.
       * <p/>
       * Sequence of Loaders is important!
       */
      private static final List<ImageLoader> imageLoaders = ImmutableList.of(
              new DefaultImageLoader(),
  			new FixedImageLoader(),
              new CMYKImageLoader(),
              new JAIImageLoader()
      );
  
      /**
       * Loads image to memory from specified inputStream.
       *
       * @return Loaded Image or null if none of Loaders could load the image
       */
      public BufferedImage loadImage(ReusableBufferedInputStream inputStream) throws IOException
      {
          IOException lastException = null;
          Optional<BufferedImage> image = Optional.absent();
          final ImageInfo imageInfo = getImageInfo(inputStream);
  
          for (ImageLoader imageLoader : imageLoaders)
          {
              try
              {
                  image = imageLoader.loadImage(inputStream, imageInfo);
                  if (image.isPresent())
                  {
  					break;
  				}
              }
              catch (IOException e)
              {
                  lastException = e;
              }
              finally
              {
                  inputStream.reset();
              }
          }
          if (image.isPresent())
          {
              return image.get();
          }
          throw new IOException("Cannot read image - none of loaders was able to create image", lastException);
      }
  
      private ImageInfo getImageInfo(ReusableBufferedInputStream inputStream) throws IOException
      {
          final ImageInfo imageInfo = new ImageInfo();
          try
          {
              imageInfo.setInput(inputStream);
              if(!imageInfo.check())
              {
                  return null;
              }
          }
          finally
          {
              inputStream.reset();
          }
          return imageInfo;
      }
  }