Background task

Preferably the import and export of images and metadata should be performed as background tasks. For this following implementations can be used:

• BackgroundMetadataImporter togeter with a MetadataImportProcessor.
• BackgroundImageImporter together with a ImageDownloader and/or ImagePreProcessor.
• BackgroundImageExporter together with a ‘ImagePostProcessor’.
• BackgroundMetadataExporter together with a ImagePostProcessor.

Your task processors should be created from by ProcessorFactory so that the task application can create new instances when needed.