Introduction to the EGE framework

The EGE is a major part of the ENRICH Garage system; its implementation is responsible for the management of conversions, transformations and validations of data performed by the ENRICH Garage. Conversions, transformations and validations are performed by a set of plug-ins compatible with the EGE plug-in specification. The software was initially created by the PSNC and OUCS as a part of the ENRICH project funded by the European Commission. EGE is distributed under an open-source license.

The EGE is a framework. It provides definitions of plug-ins (building blocks) which can be used in combination to perform a series of operations. There is also the API that can be used by other applications utilizing EGE. The image below presents the overview of the EGE architecture.

The use of the EGE is possible via the EGE API, which allows a program to:

• discover the functionality available for a particular data format that EGE provides with a current set of plug-ins;
• perform those available operations (e.g. conversion).

There are three basic types of EGE plug-ins: Recognizer, Converter and Validator.

• Recognizer - this plug-in is responsible for the recognition of the Internet Media Type (MIME type) of the given input data. For example, it will receive the input data and state that the input data has text/xml MIME type. The recognized data may then be further validated to check the format of the data.
• Validator - this plug-in is responsible for validation of the input data. For example it may be used to validate the ENRICH TEI P5 data stored in a MIME type (e.g. text/xml) either received from end user or created by one of the converters. The following notation is assumed: ENRICH TEI P5 (text/xml) - it means that validator is able to validate ENRICH TEI P5 format encoded in text/xml.
• Converter - this plug-in is responsible for converting the input data. It may be, for example, conversion from XML to Word, conversion from Word to PDF, conversion of the XML from one form to another (e.g. MASTER -> ENRICH TEI P5) or even cleaning the input data (e.g. removing redundant information).

The idea is that there may be a number of implementations for each particular plug-in type (e.g. two recognizers, five converters and three validators) connected to EGE instance. Plug-ins are connected to the EGE automatically at the start time and can be combined to perform complex iterative operations. The extensions mechanism is based on the Java Plugin Framework (http://jpf.sourceforge.net/) library. Thanks to this approach it is possible for other interested parties to extend the EGE if desired.