[jira] [Commented] (JENA-1391) Add Convenience Methods to Dataset

["A. Soroka (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/JENA-1391?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16187389#comment-16187389 ] 

A. Soroka commented on JENA-1391:
---------------------------------

Okay, finally got a little time to work on this, and a question arose: how should we handle the dynamic union of {{DatasetGraph}} {{Context}} s? Should colliding symbol-mappings override each other on some set order (left side of the union over right side or something like that)? Doing a multimap doesn't sound feasible because it would really change the contract of {{Context}}. Same thing kind of arises for callbacks.

> Add Convenience Methods to Dataset
> ----------------------------------
>
>                 Key: JENA-1391
>                 URL: https://issues.apache.org/jira/browse/JENA-1391
>             Project: Apache Jena
>          Issue Type: Improvement
>          Components: ARQ
>    Affects Versions: Jena 3.4.0
>            Reporter: Adam Jacobs
>            Assignee: A. Soroka
>            Priority: Trivial
>
> The Dataset interface could provide several convenience methods similar to the Model interface, allowing usability of RDF quads on par with RDF triples. Specific examples include,
> # add(Dataset)
> # remove(Dataset)
> # union(Dataset)
> # intersection(Dataset)
> # difference(Dataset)
> # isEmpty()
> Following is a possible implementation of these methods.
> {code:java}
>     default Dataset add(Dataset d) {
>         this.getDefaultModel().add(d.getDefaultModel());
>         d.listNames().forEachRemaining(name -> this.getNamedModel(name).add(d.getNamedModel(name)));
>         return this;
>     }
>     default Dataset remove(Dataset d) {
>         this.getDefaultModel().remove(d.getDefaultModel());
>         d.listNames().forEachRemaining(name -> this.getNamedModel(name).remove(d.getNamedModel(name)));
>         return this;
>     }
>     default Dataset union(Dataset d) {
>         return DatasetFactory.create().add(this).add(d);
>     }
>     default Dataset difference(Dataset d) {
>         Dataset output = DatasetFactory.create();
>         output.setDefaultModel(this.getDefaultModel().difference(d.getDefaultModel()));
>         this.listNames().forEachRemaining(name -> {
>             Model difference = this.getNamedModel(name).difference(d.getNamedModel(name));
>             if (!difference.isEmpty()) output.addNamedModel(name, difference);
>         });
>         return output;
>     }
>     default Dataset intersection(Dataset d) {
>         Dataset output = DatasetFactory.create();
>         output.setDefaultModel(this.getDefaultModel().intersection(d.getDefaultModel()));
>         Set<String> names = this.names();
>         names.retainAll(d.names());
>         names.forEach(name -> {
>             Model intersection = this.getNamedModel(name).intersection(d.getNamedModel(name));
>             if (!intersection.isEmpty()) output.addNamedModel(name, intersection);
>         });
>         return output;
>     }
>     default Set<String> names() {
>         Set<String> names = new HashSet<>();
>         this.listNames().forEachRemaining(names::add);
>         return names;
>     }
>     default boolean isEmpty() {
>         return this.asDatasetGraph().isEmpty();
>     }
> {code}



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