Listing all Vertices of specific class in OrientDB - spring

Question

I've recently started exploring Graph databases (in particular Neo4j and OrientDB) and have come across a problem I can't seem to put my finger on.
I'm running a local installation of OrientDB (OrientDB Server v2.0-M3 is active.).
I'm using Tinkerpops to connect to, and run queries against, the graph.
I'm using Java and Spring on a local Tomcat 7 server.
Testing my API I'm using Postman on Chrome.
Here's my faulty GET method:
#RequestMapping(value = "/articles", method = RequestMethod.GET)
public
#ResponseBody
Vector<Article> list() {
OrientGraph graph = new OrientGraph("remote:/local/path/to/orientdb/databases/mydb", "user", "password");
FramedGraphFactory factory = new FramedGraphFactory();
FramedGraph manager = factory.create(graph);
Vector<Article> articles = new Vector<>();
try {
Iterable<Vertex> vertices = graph.getVerticesOfClass("Article", false);
Iterator<Vertex> it = vertices.iterator();
if (it.hasNext()) {
do {
Article a = (Article) manager.frame(it.next(), Article.class);
articles.add(a);
} while (it.hasNext());
}
} catch (Exception e) {
e.printStackTrace();
} finally {
graph.shutdown();
}
return articles;
}
This generates the following error:
{
"timestamp": 1418562889304,
"status": 500,
"error": "Internal Server Error",
"exception": "org.springframework.http.converter.HttpMessageNotWritableException",
"message": "Could not write JSON: Database instance is not set in current thread. Assure to set it with: ODatabaseRecordThreadLocal.INSTANCE.set(db); (through reference chain: java.util.Vector[0]->$Proxy43[\"name\"]); nested exception is com.fasterxml.jackson.databind.JsonMappingException: Database instance is not set in current thread. Assure to set it with: ODatabaseRecordThreadLocal.INSTANCE.set(db); (through reference chain: java.util.Vector[0]->$Proxy43[\"name\"])",
"path": "/articles"
}
I've been trying to figure this out, trying the "fix" that the error suggests. I've also tried to use TransactionalGraph instead of OrientGraph.
Here's the catch... I'm also using a similar method for getting a single resource. This method only works if I'm using the "System.out.println", otherwise it fails with the same error.
#RequestMapping(value = "/article", method = RequestMethod.GET)
public
#ResponseBody
Article get(
#RequestParam(value = "number", required = true) long number
) {
TransactionalGraph graph = new OrientGraph("remote:/path/to/local/orientdb/orientdb/databases/mydb", "user", "password");
FramedGraphFactory factory = new FramedGraphFactory();
FramedGraph manager = factory.create(graph);
Article article = null;
try {
Iterable<Article> articles = manager.getVertices("number", number, Article.class);
article = articles.iterator().next();
System.out.println(article.getName());
} catch (Exception e) {
e.printStackTrace();
} finally {
graph.shutdown();
}
return article;
}
Any help appreciated!

Answer 1

You should leave the graph (=connection) open while you're using the result. Can you move the graph.shutdown() after browsing your result set?