Changes between Version 11 and Version 12 of ApertureRDF


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Timestamp:
10/26/05 12:54:51 (19 years ago)
Author:
anonymous
Comment:

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  • ApertureRDF

    v11 v12  
    2626Some notes on the development of Sesame 2 and how it applies to Aperture. The Sesame guys are rounding up their last efforts for releasing an alpha version. This means the code is still under development, although core interfaces are stabilizing. 
    2727 
    28 One change is that the model and model.impl packages are removed from Rio. Furthermore, Graph and GraphImpl have been removed from these packages, as well as all methods that change something in the RDF structure (e.g. Resource.addProperty). 
     28One change is that the model and model.impl packages are removed from Rio. Furthermore, Graph and !GraphImpl have been removed from these packages, as well as all methods that change something in the RDF structure (e.g. Resource.addProperty). 
    2929 
    3030Arjohn explained this decision to me as follows. Have a look at the architecture graphic on http://www.openrdf.org/doc/sesame2/system/ch02.html. The RDF Model at the bottom is the foundation for the rest of the system to manipulate RDF information. It is very awkward and may potentially result in problems when you are able to manipulate the RDF at the model level, as it bypasses the Sail stack and any inferencing, security restrictions, etc. that takes place in it. Therefore these interfaces from now on provide read-only information only. This way it is for example not possible to add properties to Resources obtained from a query result, which may result in undefined behaviour. 
    3131 
    32 If you want to manipulate statements, the Repository class is the way to go. It contains methods for adding triples as well as functionality for posing queries, extracting RDF, etc. Furthermore, a number of utility classes (URIVertex, LiteralVertex, ...) are provided that take a Repository as argument and that let you treat the RDF statements as a graph datastructure. 
     32If you want to manipulate statements, the Repository class is the way to go. It contains methods for adding triples as well as functionality for posing queries, extracting RDF, etc. Furthermore, a number of utility classes (URIVertex, !LiteralVertex, ...) are provided that take a Repository as argument and that let you treat the RDF statements as a graph datastructure. 
    3333 
    3434The only drawback of the Repository class is that it's quite a big class (note that it is a class and not an interface!). Also, just creating a repository is not enough, it always operates on top of a Sail. This architecture provides great flexibility at the cost of more code complexity.