Extracted data subsets are cached in a fixed-size region of memory, overflowing to disk (using the ehcache library);
see Section 3.2.3.
(3) Code in the Presentation Layer converts data and metadata into formats ready for transmission over the network. Images are rendered as PNG, GIF or JPEG and metadata are formatted using XML and JSON. (4) The HTTP Layer parses requests from web clients and marshals the responses. The Spring framework is used to provide modularity and to “wire” all the components of the system together.