Neo4j unmanaged extension with Spring Data - spring

I was advised to develop Neo4j extension because of poor performance due to the many calls to the Neo4j REST interface introduced by Spring Data Neo4j. For the good start I was able to run simply Neo4j extension from Neo4j documentation:
http://docs.neo4j.org/chunked/stable/server-unmanaged-extensions.html
Now I have to move some logic from my web service to Neo4j extension to make communication between them as small as possible. However, my web service is based on Spring Data Neo4j as well as Spring Data JPA, so to reuse my actual code I would like to use also Spring Data in my extension. I have found this documentation:
http://docs.spring.io/spring-data/data-neo4j/docs/current/reference/html/reference_neo4j-server.html
but it is not clear for me and there is no working example. Is there any sample code with such integration?

There is a great example on using SDN in an unmanage extension, see http://inserpio.wordpress.com/2014/04/30/extending-the-neo4j-server-with-spring-data-neo4j/.

Related

Spring Statemachine persister for spring data

We are currently investigating spring state machine and we have a very similar need to the eventservice sample with a pool and context switching using a repository, the only problem is redis is linux only (for production) and we can not lean on that... is there a clean out-of-the-box way to integrate persistence using spring data or will i have to write my own implementation for StateMachinePersister.
https://github.com/spring-projects/spring-statemachine/tree/master/spring-statemachine-samples/eventservice/src/main/java/demo/eventservice
should i go about using AbstractStateMachinePersister or StateMachinePersist?
thanks!
There is no OOB spring data integration so you need to use low level API's to build your own persist impl. Having said that, spring data support has been in my mind but just haven't had time to push it forward. PR's highly appreciated ;)
StateMachinePersister is an interface to follow which AbstractStateMachinePersister implements.

Easiest Way to Access Neo4J from Java

I want to access a Neo4j DB with Java and wanted to know what the preferred way to do this is. I just want to write a quite simple data structure to the DB.
http://neo4j.com/developer/java/ gives following options:
JDBC
Hibernate OGM
Spring Data
Rest API via Unmanaged Extensions
I looked into accessing Neo4J with JDBC and Hibernate OGM. It seems that its not worth it to use for me. JDBC gives me some trouble. So should i go with the REST way or try to fix my JDBC problems?
The JDBC driver is really a wrapper around the REST interface (as of neo4j 2.3). There is a example application how to use it. Should suffice for very simple use.
Then there is neo4j-ogm (different from Hibernate OGM) - this is an object graph mapping library, similar to hibernate in ORM world. This has minimal external dependencies and is very easy to use - ideal for cases where you want to map couple of objects into graph.
Then there is the Spring Data Neo4j project, which since version 4 uses neo4j-ogm for mapping, but adds other Spring data features, like repositories, derived finder queries, transactions ...

When to use default Spring Data REST behavior?

I recently worked on a project which uses Spring Data REST with Spring Boot. While it is GREAT to harness the power of Spring Data REST and build a powerful web service in no time, I have come to regret one thing: how tightly coupled the "presentation" layer (JSON returns) is to the underlying data structure.
Sure, I have used Projections and ResourceProcessors to manipulate the JSON, but that still does not completely sever ties with the database structure.
I want to introduce Controllers to the project, to integrate some of the "old" ways of building a web service in Spring. But how should I draw the line? I don't want to eradicate Spring Data REST from my project.
I am sure many of you have faced similar decisions, so any advice would be most appreciated!

Spring data alternatives

Currently We have an enterprise application that works with spring and JPA.
Today we are planning our next generation server.
We are debating whether to use spring-data in our project? It seems to increase productivity and development times.
Are there any alternatives to spring-data to consider? Why not using spring and JPA alone?
What do you suggest?
Bear in mind we are starting to develop from scratch so no constraints are available other than:
we use mysql and mongoDB
we code in java
we will develop client side code in GWT.
Currently we have a layered architecture.
We have a Service layer and a manager layer, which takes care for persisting and business logic. Whoever built that didn't see a good reason to insert the third DAO layer.
There are some technical benefits of Spring Data over Spring + JPA, which in a pure SQL environment, I think give Spring Data an advantage:
Spring Data uses the same CrudRepository interface for all implementations, so you'll have less effort to switch between JPA to MongoDB
Spring Data saves you writing the same methods again and again. You just add the method to the interface and it'll generate it for you (e.g. UserRepository.findByUsername())
You can save boilerplate on REST implementations for JPA, MongoDB and others (see http://projects.spring.io/spring-data-rest/)
If you wanted to experiment with other persistence or indexing services, then there are Spring Data implementations for both mature and newer technologies such as for Neo4j, Hadoop, Solr, ElasticSearch, fuzzydb.
Given that you use MySQL and MongoDB, I think Spring Data is a strong candidate, as it allows developers to code to a single data access API (Spring Data) instead of two (JPA and the MongoDB Java Client).
Regarding the existing architecture, it sounds as though your manager layer is implementing either a Rich Domain pattern, or Active Record.
Spring Data is in my view very well suited to Rich Domain when combined with injection of services using Spring's #Configurable.
Lastly, I'd say that Spring Data also gives a significant advantage when needing to implement services for things like Spring Security and Spring Social, which use MongoDB or others instead of SQL.
We did this in the fuzzydb sample webapp that can be found here. (Disclaimer: I'm the currently sole recent committer on fuzzydb, and haven't touched it for a number of years, but we did have a live service, www.fridgemountain.com, based on that code, but neglected to promote it)

How to generate Model layer, Persistence layer and service layer from a single configuration file

I am using hibernate to persist data on a MySql database.
Now I am already configuring what my business model is in the hibernate configuration file.
What I am looking for is, are there any tools that on building/deploying the application will generate the Model Layer (POJOs), Persistence Layer and the Service Layer (Business logic) for the controllers to communicate with the database server. In short I wish to generated all the basic essentials from a single configuration point.
Ant or Spring or combination of other frameworks, anything that can achieve the solution.
Any reference to an existence thread or a handful document would be highly appreciated.
Thanks in advance.
Your closest bet is Grails.
I'm not a fan of what you'd like to do. Code generation can result in a brittle system.
spring roo can be also good option to look at as your stack is based on spring framework.
Another option which can be used is MyEclipse IDE for Spring this supports code generation based on domain/table.

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