CODEWITHSUNDEEP
neo4j
Ian
Ian

Reputation: 55

Neo4j: Java API IndexHits<Node>.size() is 0

I'm trying to use the Java API for Neo4j but I seem to be stuck at IndexHits. If I query the DB with Cypher using 

START n=node:types(type="Process") RETURN n;

I get all 2087 nodes of type "Process".

In my application I have the following lines

Index<Node> nodeIndex = db.index().forNodes("types");
IndexHits<Node> hits = nodeIndex.get("type", "Process");
System.out.println("Node index size: " + hits.size());

which leads my console to spit out a value of 0. Here, db is of course an instance of GraphDatabaseService.

I expected an object that included all 2087 nodes. What am I doing wrong?

The .size() question is just the prelude to my iterator

 for(Node process : hits) { ... }

but that does not much when hits.size() == 0. According to http://api.neo4j.org/1.9.2/org/neo4j/graphdb/index/IndexHits.html this should be possible, provided there is something in hits.

Thanks in advance for your help.

Upvotes: 0

Views: 196

Answers (1)

Ian
Ian

Reputation: 55

I figured it out. Man, I feel so embarrassed...

It so happens that I had set up the DB_PATH to my default data folder, whereas the default storage folder is the default data folder plus graph.db. When I tried to run the code from that corrected DB_PATH I got an error saying that a lock file was in place because the Neo4j server was running. After shutting it down it worked perfectly.

So, if you happen to see the following error, just stop the server and run the code again:

Caused by: org.neo4j.kernel.StoreLockException: Could not create lock file at org.neo4j.kernel.StoreLocker.checkLock(StoreLocker.java:74) at org.neo4j.kernel.StoreLockerLifecycleAdapter.start(StoreLockerLifecycleAdapter.java:40) at org.neo4j.kernel.lifecycle.LifeSupport$LifecycleInstance.start(LifeSupport.java:491)

I found on several forums that you cannot run the Neo4j server and use the Java API to query it at the same time.

Upvotes: 1

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