Neo4j - Problems returning items in a relation

[warnero]

I'm trying to follow the Cineasts example and have created some nodes, a relationship between them and a test case.

I currently have two node types Event and Tag and an EventTagRelationship RelationshipEntity.

Within these I have the following (removed a lot of the code for brevity, tell me if you need more).
EventNode:

@RelatedToVia(type="EVENT_TAG")
Collection<EventTagRelationship> tagRelationships;

@RelatedTo(type="EVENT_TAG")
Set<TagNode> tags;
public EventTagRelationship addTag(TagNode tag) {
final EventTagRelationship tagRel = new EventTagRelationship(tag, this);
tagRelationships.add(tagRel);
return tagRel;
}

public Set<TagNode> getTags() {
return tags;
}

TagNode:
@RelatedTo(type = "EVENT_TAG", direction = Direction.INCOMING)
Set<EventNode> events;

EventTagRelationship:
@GraphId Long id;
@EndNode TagNode tag;
@StartNode EventNode event;

And here's my test:
@Test
public void eventCanHaveTags() {
EventNode event = template.save(new EventNode("1", "Super Duper Test Event"));
TagNode concertTag = template.save(new TagNode("1", "concert"));
TagNode bandTag = template.save(new TagNode("2", "band"));

EventTagRelationship eventBandTag = event.addTag(bandTag);
assertNotNull(eventBandTag);
template.save(eventBandTag);
EventTagRelationship eventConcertTag = event.addTag(concertTag);
assertNotNull(eventConcertTag);
template.save(eventConcertTag);

EventNode foundEvent = this.eventRepository.findById("1");
assertEquals(event, foundEvent);
assertEquals(event.getTitle(), foundEvent.getTitle());
assertEquals(2, foundEvent.getTags().size());

//now let's make sure we can find the tags themselves first
TagNode foundTag = this.tagRepository.findById("1");

assertEquals(concertTag.getName(), foundTag.getName());
System.out.println("number of tags in the event: " + foundEvent.getTags().size());

//now let's test out our relationships to ensure they are created properly
TagNode tag1 = foundEvent.getTags().iterator().next();

<--- where it starts breaking down
System.out.println("found tag relationship:" + tag1);
<---
assertEquals(eventConcertTag, tag1);
assertEquals(eventConcertTag.getTag().getName(), tag1.getName());
}

I can retrieve the event, I can retrieve the tags, but when I try and retrieve the tags related to an event I get a null object. Looking at the size of the tags set it returns 2 as expected, but the first object returns null. Here's the test output:
number of tags in the event: 2
found tag relationship:null [null]
Tests run: 1, Failures: 1, Errors: 0, Skipped: 0, Time elapsed: 11.147 sec <<< FAILURE!

Results :

Failed tests: eventCanHaveTags(com.clearboxmedia.srs.it.graph.Do mainTest): expected:<null [1], concert [1] [1]> but was:<null [null]>

Like the cineast example I have changed the toString method to output pertinent information like title, name and the [id] of the object.

Any help is greatly appreciated, thanks!

-warner

[lassewesth]

@RelatedToVia(type="EVENT_TAG")
Collection<EventTagRelationship> tagRelationships;

@RelatedTo(type="EVENT_TAG")
Set<TagNode> tags;

Warner,

Could you try changing your relationship type names so they are different?

When you say type="EVENT_TAG" for both associations, you end up with one overwriting the other.

If that doesn't work, could you share your EventNode and TagNode classes, so I can have a look. Your code otherwise looks fine and it seems it should just straightforwardly work.

Lasse

[warnero]

So, originally I just had this:
@RelatedToVia(type="EVENT_TAG")
Collection<EventTagRelationship> tagRelationships;

And then I started to read through the Cineast example further and came across this for Movie:
https://github.com/SpringSource/spri...ain/Movie.java


@RelatedTo(type = "ACTS_IN", direction = INCOMING)
Set<Person> actors;

@RelatedToVia(elementClass = Role.class, type = "ACTS_IN", direction = INCOMING)
Iterable<Role> roles;

So, roles are the actual relationship and the actors are related in the role. Do I need to specify the elementClass? In one of the examples I was looking at it didn't have the elementClass. I'll give that a shot and see if will work now.

[warnero]

Ok, that didn't work . Here's my latest output from the test:

found tag relationship:null [1], null [null] [1]
Tests run: 1, Failures: 1, Errors: 0, Skipped: 0, Time elapsed: 59.066 sec <<< FAILURE!

Results :

Failed tests: eventCanHaveTags(com.clearboxmedia.srs.it.graph.Do mainTest): expected:<null [1], concert [1] [1]> but was:<null [null]>

So, the id's are coming through, but not the event or tag names. Using the same test as before.

Here's my EventNode and TagNode classes. As well as the relationship.

EventNode:

import java.util.Collection;
import java.util.Set;

import org.neo4j.graphdb.Direction;
import org.springframework.data.neo4j.annotation.GraphId;
import org.springframework.data.neo4j.annotation.GraphPro perty;
import org.springframework.data.neo4j.annotation.NodeEnti ty;
import org.springframework.data.neo4j.annotation.RelatedT o;
import org.springframework.data.neo4j.annotation.Indexed;
import org.springframework.data.neo4j.annotation.RelatedT oVia;
import org.springframework.data.neo4j.support.index.Index Type;

import com.clearboxmedia.srs.domain.Event;

/**
* standard event intended for transport with neo4j graph database
*
* @author r351574nc3
*/
@NodeEntity
public class EventNode {
@GraphId
Long nodeId;

@Indexed(unique=true)
private String id;

@Indexed(indexType=IndexType.FULLTEXT, indexName = "event-title")
private String title;

@Indexed(indexType=IndexType.FULLTEXT, indexName = "event-description")
private String description;

public EventNode() {
super();
}

public EventNode(String id, String description) {
this.id = id;
this.description = description;
}

@RelatedToVia(type="EVENT_TAG", elementClass=EventTagRelationship.class)
Collection<EventTagRelationship> tagRelationships;

//@RelatedTo(type="EVENT_TAG")
Set<TagNode> tags;

public String getId() {
return id;
}

public void setId(String id) {
this.id = id;
}

public String getTitle() {
return title;
}

public void setTitle(String title) {
this.title = title;
}

public String getDescription() {
return description;
}

public void setDescription(String description) {
this.description = description;
}

public void setTags(Collection<EventTagRelationship> tagRelationships) {
this.tagRelationships = tagRelationships;
}

public Iterable<EventTagRelationship> getTagRelationships() {
return tagRelationships;
}

public EventTagRelationship addTag(TagNode tag) {
final EventTagRelationship tagRel = new EventTagRelationship(tag, this);
tagRelationships.add(tagRel);
return tagRel;
}

public Set<TagNode> getTags() {
return tags;
}

public void setTags(Set<TagNode> tags) {
this.tags = tags;
}

@Override
public String toString() {
return String.format("%s [%s]", title, id);
}

@Override
public boolean equals(Object o) {
if(this == o) return true;
if(o == null || getClass() != o.getClass())
return false;
EventNode event = (EventNode)o;
if(nodeId == null)
return super.equals(o);
return nodeId.equals(event.nodeId);

}
}

TagNode:


import java.util.Collection;
import java.util.Set;

import org.neo4j.graphdb.Direction;
import org.springframework.data.neo4j.annotation.GraphId;
import org.springframework.data.neo4j.annotation.Indexed;
import org.springframework.data.neo4j.annotation.NodeEnti ty;
import org.springframework.data.neo4j.annotation.RelatedT o;
import org.springframework.data.neo4j.support.index.Index Type;

@NodeEntity
public class TagNode {
@GraphId
Long nodeId;

@Indexed(unique=true)
private String id;

@Indexed(indexType=IndexType.FULLTEXT, indexName = "tags")
private String name;

@RelatedTo(type = "EVENT_TAG", direction = Direction.INCOMING)
Set<EventNode> events;

public TagNode() {
super();
}

public TagNode(String id, String name) {
this.id = id;
this.name = name;
}

public String getId() {
return id;
}

public void setId(String id) {
this.id = id;
}

public String getName() {
return name;
}

public void setName(String name) {
this.name = name;
}

public Collection<EventNode> getEvents() {
return events;
}

@Override
public String toString() {
return String.format("%s [%s]", name, id);
}

@Override
public boolean equals(Object o) {
if(this == o) return true;
if(o == null || getClass() != o.getClass())
return false;
TagNode tag = (TagNode)o;
if(nodeId == null)
return super.equals(o);
return nodeId.equals(tag.nodeId);

}

}

EventTagRelationship:

package com.clearboxmedia.srs.graph;

import java.util.Collection;
import java.util.Set;

import org.neo4j.graphdb.Direction;
import org.springframework.data.neo4j.annotation.GraphId;
import org.springframework.data.neo4j.annotation.Indexed;
import org.springframework.data.neo4j.annotation.NodeEnti ty;
import org.springframework.data.neo4j.annotation.RelatedT o;
import org.springframework.data.neo4j.support.index.Index Type;

@NodeEntity
public class TagNode {
@GraphId
Long nodeId;

@Indexed(unique=true)
private String id;

@Indexed(indexType=IndexType.FULLTEXT, indexName = "tags")
private String name;

@RelatedTo(type = "EVENT_TAG", direction = Direction.INCOMING)
Set<EventNode> events;

public TagNode() {
super();
}

public TagNode(String id, String name) {
this.id = id;
this.name = name;
}

public String getId() {
return id;
}

public void setId(String id) {
this.id = id;
}

public String getName() {
return name;
}

public void setName(String name) {
this.name = name;
}

public Collection<EventNode> getEvents() {
return events;
}

@Override
public String toString() {
return String.format("%s [%s]", name, id);
}

@Override
public boolean equals(Object o) {
if(this == o) return true;
if(o == null || getClass() != o.getClass())
return false;
TagNode tag = (TagNode)o;
if(nodeId == null)
return super.equals(o);
return nodeId.equals(tag.nodeId);

}

}

Thanks so much for the assistance!

[warnero]

Oops, actually I changed my test to test the EventTagRelationship, not the tags themselves. Still fails, but wanted to clarify.

[warnero]

For those that come along later I fixed my problem by using @Fetch before my collection and that now forces it to return the actual set of TagNodes (or relationships) that I want.