Public:BWmeta service/Transformers

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Service details
Name	BWmeta
Code location (relative to SVN root)	projects/dir/bwmeta-core
Javadoc
Contact person	Jakub Jurkiewicz
edit BWmeta format Data Model BWMeta Model Design principles 1.0.5 example 1.2.0 example 2.0.0 example Feature requests Linked Open Data Hierarchys Book Journal BWmeta usage in YADDA Java mapping Rich text in Java mapping Transformers data sources Conventions and constants Contents and attachments Internationalization Tutorial How to convert to Dublic Core? Categorizations

Background and motivation

As of 2010Q4, three versions of BWmeta format and at least three Java models of BWmeta are used in YADDA. See here for details. Serialization and deserialization is implemented for the following pairs:

	Repo	DL	Y	…
1.0.5
1.2.0
2.0.0

There are also converters between selected models:

• Y ↔ DL

Serialization of Y model to BWmeta 1.0.5 is therefore possible through the following chain of transformations:

• Y model → DL model → BWmeta 1.0.5

Conversion from DL model to Repo model is possible through:

• DL model → BWmeta 1.0.5 → Repo model

Unfortunately, many mutually-incompatible transformation interfaces are present. It is difficult to understand which transformations are possible, how to combine them, which classes should be used for that end and how to instantiate the classes.

A unified interface to all the transformations would be very helpful.

MetadataTransformerFactory and transformer interfaces

Three different transformer types are present: readers, writers and converters. Each type has a corresponding interface:

• IMetadataReader<T> deserializes an object of type T from a String or a Reader
• IMetadataWriter<T> serializes an object of type T to a String or a Writer
• IMetadataConverter<S, T> converts an object of type S to an object of type T