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https://issues.apache.org/jira/browse/JENA-624?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14991886#comment-14991886
]
ASF GitHub Bot commented on JENA-624:
-------------------------------------
Github user afs commented on a diff in the pull request:
https://github.com/apache/jena/pull/94#discussion_r44029914
--- Diff:
jena-arq/src/main/java/org/apache/jena/sparql/core/assembler/InMemDatasetAssembler.java
---
@@ -0,0 +1,67 @@
+package org.apache.jena.sparql.core.assembler;
+
+import static org.apache.jena.assembler.JA.MemoryDataset;
+import static org.apache.jena.assembler.JA.data;
+import static org.apache.jena.query.DatasetFactory.createTxnMem;
+import static org.apache.jena.riot.RDFDataMgr.loadModel;
+import static org.apache.jena.riot.RDFDataMgr.read;
+import static
org.apache.jena.sparql.core.assembler.AssemblerUtils.setContext;
+import static
org.apache.jena.sparql.core.assembler.DatasetAssemblerVocab.*;
+import static org.apache.jena.sparql.util.FmtUtils.stringForRDFNode;
+import static org.apache.jena.sparql.util.graph.GraphUtils.*;
+
+import java.util.function.Predicate;
+
+import org.apache.jena.assembler.Assembler;
+import org.apache.jena.assembler.Mode;
+import org.apache.jena.assembler.assemblers.AssemblerBase;
+import org.apache.jena.query.Dataset;
+import org.apache.jena.rdf.model.Model;
+import org.apache.jena.rdf.model.RDFNode;
+import org.apache.jena.rdf.model.Resource;
+
+/**
+ * An {@link Assembler} that creates in-memory {@link Dataset}s.
+ *
+ */
+public class InMemDatasetAssembler extends AssemblerBase {
+
+ @Override
+ public Dataset open(final Assembler assembler, final Resource root,
final Mode mode) {
+ checkType(root, MemoryDataset);
+ final Dataset dataset = createTxnMem();
+ setContext(root, dataset.getContext());
+ // Default graph can be defined with ja:graph or ja:defaultGraph
+ final Resource defaultGraphDef =
root.hasProperty(pDefaultGraph) ? getResourceValue(root,
+ pDefaultGraph) : root.hasProperty(pGraph) ?
getResourceValue(root, pGraph) : null;
--- End diff --
My suggested design was to enable files to be read directly into an
in-memory assembler. That to me is the major use case for getting data into
dataset.
Building a model and copying it in (ja:defaultGraph, ja:namedGraph) allows
precomputation (e.g. rules) - I think that's a specialist use case (if it's
confusing, lets leave that for the general dataset).
> Develop a new in-memory RDF Dataset implementation
> --------------------------------------------------
>
> Key: JENA-624
> URL: https://issues.apache.org/jira/browse/JENA-624
> Project: Apache Jena
> Issue Type: Improvement
> Reporter: Andy Seaborne
> Assignee: A. Soroka
> Labels: gsoc, gsoc2015, java, linked_data, rdf
>
> The current (Jan 2014) Jena in-memory dataset uses a general purpose
> container that works for any storage technology for graphs together with
> in-memory graphs.
> This project would develop a new implementation design specifically for RDF
> datasets (triples and quads) and efficient SPARQL execution, for example,
> using multi-core parallel operations and/or multi-version concurrent
> datastructures to maximise true parallel operation.
> This is a system project suitable for someone interested in datatbase
> implementation, datastructure design and implementation, operating systems or
> distributed systems.
> Note that TDB can operate in-memory using a simulated disk with
> copy-in/copy-out semantics for disk-level operations. It is for faithful
> testing TDB infrastructure and is not designed performance, general in-memory
> use or use at scale. While lesson may be learnt from that system, TDB
> in-memory is not the answer here.
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