Jena [1] is a Java framework for building Semantic Web applications. One of the fundamental part of Semantic Web is the ontology which is a formal specification of a shared conceptualization[2]. Jena provides a programmatic environment for ontologies, but it includes also both a rule—based inference and a SPARQL query engine. In particular, Jena provides several built-ins rule files. They are functions which require some parameters as input and return others as output. Unfortunately, with default built-ins, there are lots of limitations. You cannot do operations such as : calculating the difference between two dates and establishing the minimum and maximum between two dates. On the other hand, it is possible to compare two dates. Built-ins can be extended and the aim of this study is to create customized built-ins, in order to use them in a huge variety of cases where default built-ins are not useful In particular, the attention has been focused on built-ins known as Data—Time. They allow to manage Dates and Times values since there are just few builtins for this purpose. Now, it is possible to calculate the difference between one value typed as “XSDDateTime” and another one; you can easily know how many days are between the actual date and another one. Finally, SPARQL QUERIES [3] have been performed also, to get the minimum and the maximum date from a dataset which is not possible to take over with normal built-ins. All of this work has been carried out under the project called “AALISABETH”.
New Jena built-ins for managing Dates and Times
QUADRINI, MICHELA;CULMONE, Rosario;GIULIODORI, PAOLO
2014-01-01
Abstract
Jena [1] is a Java framework for building Semantic Web applications. One of the fundamental part of Semantic Web is the ontology which is a formal specification of a shared conceptualization[2]. Jena provides a programmatic environment for ontologies, but it includes also both a rule—based inference and a SPARQL query engine. In particular, Jena provides several built-ins rule files. They are functions which require some parameters as input and return others as output. Unfortunately, with default built-ins, there are lots of limitations. You cannot do operations such as : calculating the difference between two dates and establishing the minimum and maximum between two dates. On the other hand, it is possible to compare two dates. Built-ins can be extended and the aim of this study is to create customized built-ins, in order to use them in a huge variety of cases where default built-ins are not useful In particular, the attention has been focused on built-ins known as Data—Time. They allow to manage Dates and Times values since there are just few builtins for this purpose. Now, it is possible to calculate the difference between one value typed as “XSDDateTime” and another one; you can easily know how many days are between the actual date and another one. Finally, SPARQL QUERIES [3] have been performed also, to get the minimum and the maximum date from a dataset which is not possible to take over with normal built-ins. All of this work has been carried out under the project called “AALISABETH”.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
