Github user dick-twocows commented on a diff in the pull request:
https://github.com/apache/jena/pull/233#discussion_r110244425
--- Diff:
jena-arq/src/main/java/org/apache/jena/sparql/core/mosaic/ThreadProxy.java ---
@@ -0,0 +1,100 @@
+package org.apache.jena.sparql.core.mosaic;
+
+import java.util.concurrent.Callable;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Future;
+import java.util.concurrent.LinkedBlockingQueue;
+import java.util.concurrent.ThreadFactory;
+import java.util.concurrent.ThreadPoolExecutor;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicInteger;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * A Thread proxy which performs actions using one thread (the proxy).
+ * Internally an ExecutorService with one Thread is used with the action
methods execute/submit(Runnable) and submit(Callable<T>).
+ * Calls to the action methods are FIFO actioned through the
LinkedBlockingQueue of the ExecutorService.
+ * Useful where Thread affinity is required in a parallel processing
environment, e.g. .parallelStream().flatMap(...)
+ *
+ * @author dick
+ *
+ */
+public class ThreadProxy {
+
+ private static final Logger LOGGER =
LoggerFactory.getLogger(ThreadProxy.class);
+
+ protected static final IDFactory ID_FACTORY =
IDFactory.valueOf(ThreadProxy.class);
+
+ protected static final ThreadGroup THREAD_GROUP = new
ThreadGroup(ThreadProxy.class.getName());
+
+ protected final String id;
+
+ protected final String createdBy;
+
+ protected final ExecutorService executorService;
+
+ protected final AtomicInteger executeCount;
+
+ protected final AtomicInteger submitCount;
+
+ protected final AtomicInteger exceptionCount;
+
+ public ThreadProxy() {
+ super();
+ id = ID_FACTORY.next();
+ createdBy = Thread.currentThread().getName();
+ executorService = new ThreadPoolExecutor(1, 1,
--- End diff --
Yes and to close the executor, also the parallel streams in mosaic via the
transactional distributed use a fork join and create a thread proxy per dataset
graph touchedâ. Otherwise the system default fork join gets used and that
limits the threads to the current processor current across all requests!
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