com.day.cq.dam.api.handler

Interface AssetHandler

All Known Implementing Classes:

AbstractAssetHandler, StandardImageHandler

public interface AssetHandler

The AssetHandler inteface specifies the handling of assets, specifically during importing or updating the binary of an asset.

Method Summary

Modifier and Type	Method and Description
boolean	canHandleSubAssets() Indicates if the handler supports processing of sub assets
void	createThumbnails(Asset asset) Creates thumbnails for this asset.
void	createThumbnails(Asset asset, java.util.Collection<ThumbnailConfig> configs) Thumbnails of an asset are created during import/update of an asset and it's original binary.
void	createThumbnails(Asset asset, Rendition rendition, java.util.Collection<ThumbnailConfig> configs) Creates thumbnails for an Assets particular Rendition.
void	exportAsset(Asset asset, java.io.OutputStream stream) This method exports the asset into the given OutputStream.
ExtractedMetadata	extractMetadata(Asset asset) This method is used by the ExtractMetadataProcess as part of the DAM Update Asset workflow during import or update of an asset.
java.awt.image.BufferedImage	getImage(Rendition rendition) This method retrieves the graphical representation of an Assets given Rendition.
java.awt.image.BufferedImage	getImage(Rendition rendition, java.awt.Dimension maxDimension) This method retrieves the graphical representation of an Assets given Rendition.
java.lang.String[]	getMimeTypes() This method returns the mime types a particular AssetHandler supports.
java.util.Iterator<? extends AssetRelation>	processRelated(Asset asset) extracts and stores the links to the assets related with provided asset.
java.util.List<java.lang.String>	processSubAssets(Asset asset) Handler implementations may choose to support sub asset creation for the file types it handles.

Method Detail

canHandleSubAssets

boolean canHandleSubAssets()

Indicates if the handler supports processing of sub assets

Returns:

true if handler is able to process sub assets

createThumbnails

void createThumbnails(Asset asset,
                      java.util.Collection<ThumbnailConfig> configs)
               throws java.io.IOException

Thumbnails of an asset are created during import/update of an asset and it's original binary. Currently this method is used by the CreateThumbnailProcess and the CommandLineProcess as part of the DAM Update Asset workflow. Implementations may choose to create asset thumbnails for every entry in the thumbnailConfigs list argument, to not create any thumbnails at all, or to create a generic thumbnail independent of the given config. Thumbnails themselves are renditions of an asset and must be persisted as such (see Asset.addRendition(String, java.io.InputStream, String)).

The thumbnail renditions are created depending on the given configuration list:

 {
     height:h1,
     width: w1,
     doCenter: true (or false)
 },
 {
 ...
 }
 

Sample:

   ...
   final ArrayList<Map<String, Object>> config = new ArrayList<Map<String, Object>>();

   config.add(new HashMap<String, Object>() {{
       put("width", 140);
       put("height", 100);
       put("doCenter", true);
   }});
   config.add(new HashMap<String, Object>() {{
       put("width", 80);
       put("height", 80);
       put("doCenter", true);
   }});

  handler.createThumbnailsExt(
           getTiff(),
           asset.adaptTo(Node.class).getNode("jcr:content/renditions"),
           session,
           config);
  ...
 

Parameters:

asset - the asset/file for which the thumbnails are generated

configs - thumbnail configurations

Throws:

java.io.IOException - is thrown in case while an error occurred while fetching the image

Since:

5.4.0

See Also:

Asset.addRendition(String, java.io.InputStream, String), Asset.getRenditions(), ), Asset.getRendition(com.day.cq.dam.api.RenditionPicker)

createThumbnails

void createThumbnails(Asset asset)
               throws java.io.IOException

Creates thumbnails for this asset. Which thumbnails are created is automatically derived from the existing thumbnails (renditions with the cq5dam.thumbnail prefix). This essentially amounts to re-creating existing thumbnails.

Parameters:

asset - The asset for which to create thumbnails.

Throws:

java.io.IOException - If an error occurred while extracting the image.

createThumbnails

void createThumbnails(Asset asset,
                      Rendition rendition,
                      java.util.Collection<ThumbnailConfig> configs)
               throws java.io.IOException

Creates thumbnails for an Assets particular Rendition.

Parameters:

asset - The asset for which to created thumbnails.

rendition - The rendition serving as the thumbnail basis.

configs - The thumbnail configurations.

Throws:

java.io.IOException - If an error occurred extracting an image from the rendition.

exportAsset

void exportAsset(Asset asset,
                 java.io.OutputStream stream)
          throws AssetHandlerException

This method exports the asset into the given OutputStream. The Assets original binary is served.

Parameters:

asset - The asset to export.

stream - The output stream to export into.

Throws:

AssetHandlerException - If an error occurred during export.

Since:

5.4.0

extractMetadata

ExtractedMetadata extractMetadata(Asset asset)

This method is used by the ExtractMetadataProcess as part of the DAM Update Asset workflow during import or update of an asset. Implementations must return an ExtractedMetadata object, which may be empty if no metadata is extracted, or contains the metadata values extracted from the binary being imported/updated at the time. The ExtractMetadataProcess will later save the metadata contained in ExtractedMetadata to the asset's metadata node (e.g. /content/dam/geometrixx/banners/banner-mono.png/jcr:content/metadata). Implementations are free to decide which and how many metadata values are extracted.

The method argument represents the Node of type nt:file holding the binary content or the DAM Asset node (type dam:Asset), for which its original rendition would be retrieved.

Parameters:

asset - The Asset, from whose original binary metadata will extracted.

Returns:

The extracted metadata.

Since:

5.4.0

getImage

java.awt.image.BufferedImage getImage(Rendition rendition)
                               throws java.io.IOException

This method retrieves the graphical representation of an Assets given Rendition. For images the BufferedImage of the original image is returned, for other formats the first page is retrieved as BufferedImage

Parameters:

rendition - The rendition for which to retrieve its graphical representation.

Returns:

BufferedImage if a graphical representation exists, otherwise null

Throws:

java.io.IOException - in case an error is thrown while fetching the buffered image

Since:

5.4.0

getImage

java.awt.image.BufferedImage getImage(Rendition rendition,
                                      java.awt.Dimension maxDimension)
                               throws java.io.IOException

This method retrieves the graphical representation of an Assets given Rendition. For images the BufferedImage of the original image is returned, for other formats the first page is retrieved as BufferedImage.

If maxDimension is given, the handler should return an image where no dimension extends the given value. This can be used to reduce the memory footprint of large buffered images if the full resolution is not needed.

Parameters:

rendition - The rendition for which to retrieve its graphical representation.

maxDimension - optional constraint for the maximal dimension of the image.

Returns:

BufferedImage if a graphical representation exists, otherwise null

Throws:

java.io.IOException - in case an error is thrown while fetching the buffered image

Since:

5.4.0

getMimeTypes

java.lang.String[] getMimeTypes()

This method returns the mime types a particular AssetHandler supports.

Returns:

mime type, e.g. image/jpg

processSubAssets

java.util.List<java.lang.String> processSubAssets(Asset asset)

Handler implementations may choose to support sub asset creation for the file types it handles. The method is called by the CreateSubAssetsProcess during import/update of an asset and its binary, as part of the DAM Update Asset workflow. Sub assets represent fragments of the original asset, for example every page of a multi-page PDF document are sub assets. Sub assets are stored as assets themselves under the parent asset. Sub assets are stored in the subassets folder of the main asset, e.g. at /content/dam/geometrixx/documents/ECM Artikel.pdf/subassets.

The asset argument represents the Node of type nt:file holding the binary content or the DAM Asset node (type dam:Asset), for which its original rendition would be retrieved.

Parameters:

asset - asset to extract sub assets

Returns:

List constaining all paths to the newly created assets

See Also:

canHandleSubAssets(), Asset.isSubAsset()

processRelated

java.util.Iterator<? extends AssetRelation> processRelated(Asset asset)

extracts and stores the links to the assets related with provided asset.

Parameters:

asset - asset to process

Returns:

Iterator of AssetRelation or an empty iterator if no related assets are available