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https://issues.apache.org/jira/browse/JENA-203?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13197939#comment-13197939
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Henry Story commented on JENA-203:
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With a bit of help from Damian I did get the RDF/XML parser to be asynchronous
using com.fasterxml.aalto asynchronous parser [1].
I had to adapt Damian's jena.rdf.arp.StAX2SAX - which I called AsyncJenaParser
[2] . This is then used by the URLFetcher class [3]. This class
extends the async_http_client by ning [4], to fetch RDF.
Currently it can only fetch RDF/XML, and with a bit more work, any XML format.
What is missing is the Turtle parsers and JSON parsers
The URLFetcher could be a bit more general and just pass on the data it
receives to some actors. That would remove the parser processing from the IO
thread, and allow the fetcher to be more general.
There is perhaps something here that can be integrated by Jena. The
AsyncJenaParser perhaps?
Henry
[1] http://www.cowtowncoder.com/blog/archives/2011/03/entry_451.html
[2]
https://dvcs.w3.org/hg/read-write-web/file/aa9074df0635/src/main/java/patch/AsyncJenaParser.java
[3]
https://dvcs.w3.org/hg/read-write-web/file/d9c1f87eee55/src/main/scala/cache/WebFetcher.scala
[4] all classes can be found in the build file
https://dvcs.w3.org/hg/read-write-web/file/aa9074df0635/project/build.scala
> support for Non Blocking Parsers
> --------------------------------
>
> Key: JENA-203
> URL: https://issues.apache.org/jira/browse/JENA-203
> Project: Jena
> Issue Type: Improvement
> Reporter: Henry Story
>
> In a Linked Data environment servers have to fetch data off the web. The
> speed at which such data
> is served can be very slow. So one wants to avoid using up one thread for
> each connections (1 thread =
> 0.5 to 1MB approximately). This is why Java NIO was developed and why servers
> such as Netty
> are so popular, why http client libraries such as
> https://github.com/sonatype/async-http-client are more
> and more numerous, and why framewks such as http://akka.io/ which support
> relatively lightweight
> actors (500 bytes per actor) are growing more viisible.
> Unless I am mistaken the only way to parse some content is using methods that
> use an
> InputStream such as this:
> val m = ModelFactory.createDefaultModel()
> m.getReader(lang.jenaLang).read(m, in, base.toString)
> That read call blocks. Would it be possible to have an API which allows
> one to parse a document in chunks as they arrive from the input?
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