Convert Node to @NodeEntity?

[Zesen Qian]

Hello, I 'am using Spring data neo4j to manage the database, but sometimes I get some Node and Relationship from Neo4jTemplate, and I would like to convert these to @NodeEntity and @RelationshipEntity objects. How can I do this?

[Michael Hunger]

template.projectTo(node, Entity.class)

Am 28.07.2015 um 09:47 schrieb Zesen Qian <qzs...@gmail.com>:

Hello, I 'am using Spring data neo4j to manage the database, but sometimes I get some Node and Relationship from Neo4jTemplate, and I would like to convert these to @NodeEntity and @RelationshipEntity objects. How can I do this?

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[Zesen Qian]

Hello Michael,
Thanks for your reply. I tried this and got the following exception:

Caused by: org.neo4j.graphdb.NotFoundException: '__type__' on http://dorm.riaqn.com:7474/db/data/relationship/856
    at org.neo4j.rest.graphdb.entity.RestEntity.getProperty(RestEntity.java:101)
    at org.springframework.data.neo4j.support.typerepresentation.AbstractIndexBasedTypeRepresentationStrategy.readAliasFrom(AbstractIndexBasedTypeRepresentationStrategy.java:126)
    at org.springframework.data.neo4j.support.mapping.TRSTypeAliasAccessor.readAliasFrom(TRSTypeAliasAccessor.java:36)
    at org.springframework.data.neo4j.support.mapping.TRSTypeAliasAccessor.readAliasFrom(TRSTypeAliasAccessor.java:26)
    at org.springframework.data.convert.DefaultTypeMapper.readType(DefaultTypeMapper.java:102)
    at org.springframework.data.convert.DefaultTypeMapper.getDefaultedTypeToBeUsed(DefaultTypeMapper.java:165)
    at org.springframework.data.convert.DefaultTypeMapper.readType(DefaultTypeMapper.java:142)
    at org.springframework.data.neo4j.support.mapping.Neo4jEntityConverterImpl.read(Neo4jEntityConverterImpl.java:78)
    at org.springframework.data.neo4j.support.mapping.Neo4jEntityPersister$CachedConverter.read(Neo4jEntityPersister.java:170)
    at org.springframework.data.neo4j.support.mapping.Neo4jEntityPersister.createEntityFromState(Neo4jEntityPersister.java:192)
    at org.springframework.data.neo4j.support.mapping.Neo4jEntityPersister.projectTo(Neo4jEntityPersister.java:216)
    at org.springframework.data.neo4j.support.mapping.Neo4jEntityPersister.projectTo(Neo4jEntityPersister.java:206)
    at org.springframework.data.neo4j.support.Neo4jTemplate.projectTo(Neo4jTemplate.java:236)

A simple curl give me the following:

➜  ~  curl http://dorm.riaqn.com:7474/db/data/relationship/856
{
  "extensions" : { },
  "metadata" : {
    "id" : 856,
    "type" : "FOLLOW"
  },
  "property" : "http://dorm.riaqn.com:7474/db/data/relationship/856/properties/{key}",
  "start" : "http://dorm.riaqn.com:7474/db/data/node/333",
  "self" : "http://dorm.riaqn.com:7474/db/data/relationship/856",
  "end" : "http://dorm.riaqn.com:7474/db/data/node/81",
  "type" : "FOLLOW",
  "properties" : "http://dorm.riaqn.com:7474/db/data/relationship/856/properties",
  "data" : { }
}                                                                                                                                      

在 2015年7月28日星期二 UTC+8下午4:31:42，Michael Hunger写道：

[Zesen Qian]

I found the reason of this exception. Because I use template.getorcreaterelationship to create the relation(instead of repository.save), so the property "__type__" is not persisted.
I add __type__=Follow to the properties when creating relationships, and the problem is solved.
Thanks for your help.

在 2015年7月28日星期二 UTC+8下午7:03:07，Zesen Qian写道：

[Michael Hunger]

there is also 

template.postEntityCreation(node, Entity.class) to do that for you

Michael

[Zesen Qian]

Seems that the method is deprecated and may be removed in the future, and it will introduce overhead to the operation(since it do an extra api query to add the property).

在 2015年7月29日星期三 UTC+8上午6:52:21，Michael Hunger写道：

[Michael Hunger]

it does the right thing depending on the configured type representation strategy.

As I deprecated it it was just to document that it should not be part of the public API