Package org.apache.xmlgraphics.image.loader.pipeline

Class ImageProviderPipeline

  • public class ImageProviderPipeline
extends java.lang.Object
    Represents a pipeline of ImageConverters with an ImageLoader at the beginning of the pipeline.

    • Field Detail

      • log

        protected static final org.apache.commons.logging.Log log
        logger

    • Constructor Detail

      • ImageProviderPipeline

        public ImageProviderPipeline​(ImageCache cache,
                             ImageLoader loader)
        Main constructor.
        Parameters:
        cache - the image cache (may be null if no caching is desired)
        loader - the image loader to drive the pipeline with

      • ImageProviderPipeline

        public ImageProviderPipeline​(ImageLoader loader)
        Constructor for operation without caching.
        Parameters:
        loader - the image loader to drive the pipeline with

      • ImageProviderPipeline

        public ImageProviderPipeline()
        Default constructor without caching and without an ImageLoader (or the ImageLoader may be set later).

    • Method Detail

      • execute

        public Image execute​(ImageInfo info,
                     java.util.Map<java.lang.String,​java.lang.Object> hints,
                     ImageSessionContext context)
              throws ImageException,
                     java.io.IOException
        Executes the image converter pipeline. First, the image indicated by the ImageInfo instance is loaded through an ImageLoader and then optionally converted by a series of ImageConverters. At the end of the pipeline, the fully loaded and converted image is returned.
        Parameters:
        info - the image info object indicating the image to load
        hints - a Map of image conversion hints
        context - the session context
        Returns:
        the requested image
        Throws:
        ImageException - if an error occurs while loader or converting the image
        java.io.IOException - if an I/O error occurs

      • execute

        public Image execute​(ImageInfo info,
                     Image originalImage,
                     java.util.Map<java.lang.String,​java.lang.Object> hints,
                     ImageSessionContext context)
              throws ImageException,
                     java.io.IOException
        Executes the image converter pipeline. First, the image indicated by the ImageInfo instance is loaded through an ImageLoader and then optionally converted by a series of ImageConverters. At the end of the pipeline, the fully loaded and converted image is returned.
        Parameters:
        info - the image info object indicating the image to load
        originalImage - the original image to start the pipeline off or null if an ImageLoader is used
        hints - a Map of image conversion hints
        context - the session context
        Returns:
        the requested image
        Throws:
        ImageException - if an error occurs while loader or converting the image
        java.io.IOException - if an I/O error occurs

      • forceCaching

        protected Image forceCaching​(Image img)
                      throws java.io.IOException
        In some cases the provided Image is not cacheable, nor is any of the intermediate Image instances (for example, when loading a raw JPEG file). If the image is loaded over a potentially slow network, it is preferrable to download the whole file and cache it in memory or in a temporary file. It's not always possible to convert an Image into a cacheable variant.
        Parameters:
        img - the Image to investigate
        Returns:
        the converted, cacheable Image or null if the Image cannot be converted
        Throws:
        java.io.IOException - if an I/O error occurs

      • setImageLoader

        public void setImageLoader​(ImageLoader imageLoader)
        Sets the ImageLoader that is used at the beginning of the pipeline if the image is not loaded, yet.
        Parameters:
        imageLoader - the image loader implementation

      • addConverter

        public void addConverter​(ImageConverter converter)
        Adds an additional ImageConverter to the end of the pipeline.
        Parameters:
        converter - the ImageConverter instance

      • toString

        public java.lang.String toString()
        Overrides:
        toString in class java.lang.Object

      • getConversionPenalty

        public int getConversionPenalty()
        Returns the overall conversion penalty for the pipeline. This can be used to choose among different possible pipelines.
        Returns:
        the overall penalty (a non-negative integer)

      • getConversionPenalty

        public Penalty getConversionPenalty​(ImageImplRegistry registry)
        Returns the overall conversion penalty for the pipeline. This can be used to choose among different possible pipelines.
        Parameters:
        registry - the image implementation registry
        Returns:
        the overall penalty (a non-negative integer)

      • getTargetFlavor

        public ImageFlavor getTargetFlavor()
        Returns the target flavor generated by this pipeline.
        Returns:
        the target flavor