Any feedback? Is this safe?
On Monday, April 10, 2017 at 8:01:55 PM UTC-4, odbuser wrote:
>
> I would like to use Graph Elements (not just the graph) across threads. I
> understand what is necessary to use the Graph across threads but want to
> know if an already retrieved Element (and iterator) can also be used across
> threads (safely) in a similar manner (simply by calling graph.makeActive()
> before using the graph in each thread).
>
> The following code works as expected. It uses 2 threads. Everything
> works as expected as the reused graph is only used from one thread at a
> time (not concurrent). This type of behavior is necessary in order to pass
> state from thread to thread. Otherwise, I'd have to retrieve the vertices
> in each thread (by passing ids I guess) which would be highly inefficient -
> especially when the results are large and can't fit in memory.
>
> Note that the Element.getGraph() will return null on the new thread but
> will return the graph properly if you call OrientBaseGraph.makeActive()
> first.
>
> @Test
> public void testGraphAcrossThread() throws InterruptedException,
> ExecutionException {
> //Create the graph
> OrientBaseGraph g = new OrientGraphFactory(
> "plocal:tmp/orientdb/thread").getTx();
>
> //Create a vertex
> OrientVertex oV = g.addVertex(null).setProperties("name", "Luigi"
> );
>
> //Query for the vertex
> final Iterator<Vertex> iterator = g.getVertices("name","Luigi").
> iterator();
>
> //Create a new thread and submit a runnable that uses the same
> Graph
> Future<?> future = Executors.newSingleThreadExecutor().submit(new
> Runnable() {
> @Override
> public void run() {
> //Element's graph will be null on this thread
> Assert.assertNull(oV.getGraph());
>
> //Make the graph active on the new thread
> g.makeActive();
>
> //Element's graph is now non-null on this thread
> Assert.assertNotNull(oV.getGraph());
>
> //Everything works as expected
> Assert.assertTrue(iterator.hasNext());
> Assert.assertEquals("Luigi", oV.getProperty("name"));
> Assert.assertEquals("Luigi", (String)iterator.next().
> getProperty("name"));
> oV.setProperty("age", "20");
> }
> });
>
> //Call get on the future so that the thread's work completes
> before using the graph on this thread
> future.get();
>
> //Graph is not null like it was on a new thread
> Assert.assertNotNull(oV.getGraph());
>
> //But the everything still works as expected
> Assert.assertEquals("20", oV.getProperty("age"));
> Iterator<Vertex> iterator2 = g.getVertices("name","Luigi").
> iterator();
> Assert.assertEquals("Luigi", (String)iterator2.next().getProperty(
> "name"));
>
> g.commit();
> g.drop();
> }
>
>
>
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