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https://issues.apache.org/jira/browse/JENA-2302?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17502552#comment-17502552
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Claus Stadler commented on JENA-2302:
-------------------------------------
I have hacked up an initial approach using GSON - in order to deal with headers
anywhere in the stream there is the BufferedRowSet header which buffers
bindings until it encounters a header.
[RowSetJson|https://github.com/Scaseco/jenax/blob/57ba3b044d98d716ace6db62f23b7b678a0726f7/jenax-io-parent/jenax-io-core/src/main/java/org/aksw/jenax/io/json/RowSetJson.java#L39]
[BufferedRowSet|https://github.com/Scaseco/jenax/blob/57ba3b044d98d716ace6db62f23b7b678a0726f7/jenax-io-parent/jenax-io-core/src/main/java/org/aksw/jenax/io/json/BufferedRowSet.java#L32]
I still need to do testing and add all the additional validation of the
original RowSetJSON
And of course I need to check how hard it is to switch to any of the other JSON
APIs - but overall its a first working solution.
> RowSetReaderJSON is not streaming
> ---------------------------------
>
> Key: JENA-2302
> URL: https://issues.apache.org/jira/browse/JENA-2302
> Project: Apache Jena
> Issue Type: Bug
> Components: ARQ
> Affects Versions: Jena 4.5.0
> Reporter: Claus Stadler
> Priority: Major
>
> Retrieving all data from our TDB2 endpoint with jena 4.5.0-SNAPSHOT is no
> longer streaming for the JSON format. I tracked the issue to RowSetReaderJson
> which reads everything into in memory (and then checks whether it is a SPARQL
> ASK result)
> {code:java}
> public class RowSetReaderJson {
> private void parse(InputStream in) {
> JsonObject obj = JSON.parse(in); // !!! Loads everything !!!
> // Boolean?
> if ( obj.hasKey(kBoolean) ) { ... }
> }
> }
> {code}
> Streaming works when switching the to RS_XML in the example below:
> {code:java}
> public class Main {
> public static void main(String[] args) {
> System.out.println("Test Started");
> try (QueryExecution qe = QueryExecutionHTTP.create()
>
> .acceptHeader(ResultSetLang.RS_JSON.getContentType().getContentTypeStr())
> .endpoint("http://moin.aksw.org/sparql";).queryString("SELECT
> * { ?s ?p ?o }").build()) {
> qe.execSelect().forEachRemaining(System.out::println);
> }
> System.out.println("Done");
> }
> }
> {code}
> For completeness, I can rule out any problem with TDB2 because streaming of
> JSON works just fine with:
> {code:bash}
> curl --data-urlencode "query=select * { ?s ?p ?o }"
> "http://moin.aksw.org/sparql";
> {code}
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