Neo4j Procedure Template

This project is an example you can use to build user defined procedures, functions and aggregation functions in Neo4j. It contains two procedures, for reading and updating a full-text index.

To try this out, simply clone this repository and have a look at the source and test code (including Test-Server-Setup).

This project requires a Neo4j 3.5.x dependency.

User Defined Procedure

The user defined procedure allows you to index and search a explicit Lucene index within Neo4j.

Given properties of a node can be added to indexes named according to the labels of the node. After that the data can be searched with Lucene Syntax.

See FullTextIndex.java and the LegacyFullTextIndexTest.java.

MATCH (n:Person)
CALL example.index(id(n), ['name']);

CALL example.search('Person','name:Jo*') YIELD nodeId

User Defined Function

The user defined function is a simple join function that joins a list of strings using a delimiter.

See Join.java and the JoinTest.java.

RETURN example.join(['A','quick','brown','fox'],' ') as sentence

User Defined Aggregation Function

The aggregation function example.last returns the last row of an aggregation.

MATCH (n:Person)
WITH n ORDER BY n.born
RETURN n.born, example.last(n) as last

See Last.java and the LastTest.java.

Building

This project uses maven, to build a jar-file with the procedure in this project, simply package the project with maven:

mvn clean package

This will produce a jar-file,target/procedure-template-1.0.0-SNAPSHOT.jar, that can be deployed in the plugin directory of your Neo4j instance.

License

Apache License V2, see LICENSE